RU2437948C1 - Light valve of internal combustion engine of composite heat proof material on base of titanium and its inter-metallides and procedure for its manufacture - Google Patents

Abstract

FIELD: machine building. ^ SUBSTANCE: valve with rod of cylinder shape, head of disk shape and section of smooth transition between them is manufactured by procedure of granule metallurgy of heat proof material on base of titanium or its inter-metallides. Material consists of spherical granules of matrix and of strengthening or plastic additive, and also, of nano-dimension thermo-strengthening powder additive out of granules of matrix thermodynamic stable and resistant to material and to strengthening or plastic additive in form of oxides, carbides, nitrides or borides of metals and/or non-metals taken at a specified ratio. A blank of the valve of spherical granules is compacted and is subjected to thermal and deformation treatment under modes chosen depending on phase composition of material of matrix and additives. ^ EFFECT: long-term operability of valves of internal combustion engines in wide range of working temperatures. ^ 14 cl, 7 dwg, 3 tbl, 6 ex

Description

The invention relates to mechanical engineering and metallurgy, namely to engine building, metal composite materials and the manufacture of blanks or products from metal powders and, in particular, can be used in reciprocating internal combustion engines (ICE) of various purpose machines and power plants.

Over the long period of development of internal combustion engines for various purposes and taking into account the experience of their operation, designs, materials and methods of thermal hardening for intake and exhaust valves have been worked out, which mainly ensure the reliability and durability of engine operation. As materials for the manufacture of ICE valves, special steel grades and nickel alloys are usually used, which have a high density (ρ = 7.63 ... 8.4 g / cm ³ ). The mass of valves made from traditional materials is significant, which is a negative factor for valve mechanisms of modern high-speed engines operating at high speeds and accelerations.

High inertial loads due to the mass of the valves increase the load on the links of the valve mechanism. This, in turn, causes a decrease in the reliability and reliability of the gas distribution mechanism and the engine as a whole. The weight of the valves is one of the limiting factors in creating highly accelerated engines of special design and engines for sports purposes. Piston ICE valves, especially exhaust valves, work when exposed to increased heat loads. So, taking into account the variety of piston internal combustion engines produced: stationary, transport (ship, diesel, tractor, aviation, automobile, motorcycle) and special designs, the steady-state temperatures in the center of the valve heads are 500 ... 650 ° C for inlet valves, 650 ... for exhaust valves 900 ° C. Moreover, in the transition zone from the valve head to the stem, large temperature differences occur, reaching 200-300 ° C in the axial direction. In the valve head itself, temperature differences reach 150-200 ° C in the radial and circumferential directions. This causes a high level of temperature stresses in the valve head and in the transition zone to the rod, and often the destruction of valves as a result of thermal cycling (see Internal Combustion Engines: Design and Strength Analysis of Piston and Combined Engines. Edited by A.S. Orlin, M .G. Kruglova. - 4th ed., Revised and enlarged. - M.: Mechanical Engineering, 1984, p. 247-250, 258. / Raikov I.Ya., Rytvinsky G.N. Design of automobile and tractor engines . - M.: Higher School, 1986, p.115-119).

A further increase in the technical level of internal combustion engines, taking into account a significant reduction in fuel consumption and toxic emissions, requires the search for new technical solutions. One of these solutions is to reduce the moving masses of the valve mechanism and, first of all, the mass of the valves. Studies have shown that reducing valve mass by 50% can reduce fuel consumption, exhaust emissions and noise, increase engine torque, reliability and durability (see Untersuchung mit Ventilen aus Leichtbau-Werkstoffen. MTZ Motortechnische Zeitschrift 60 (1999) 9, p. 590-603).

In order to reduce the weight of the valves, increase their heat resistance and create the prerequisites for improving the design of ICE with significantly improved indicators of fuel economy and exhaust emissions, a search is being made for new materials with low density and high heat resistance, as well as methods for manufacturing gas distribution valves from them. Of the new materials, these conditions are largely met by alloys based on titanium and titanium intermetallic compounds of the Ti-Al and Ti-Al-Nb systems, which have high heat resistance (up to 900 ° C) at low density (ρ = 3.7-5.2 g / cm ³ ).

Known titanium intermetallic Ti ₂ AlNb (O-phase), formed when the content in the α ₂ phase of niobium in the amount of 25 ... 27% (atom.) (See Banerjee D, Gogia AK et al., 1993 The physical metallurgy of Ti ₃ Al based alloys. In: Darolia R, Levandovskii JJ et ai, Structural Intermetallics.TMS, Warrendale, PA, pp. 19-31), and O-phase alloys (Ti ₂ AlNb) (see Banerjee D, Gogia AK et al., 1993. The physical metallurgy of Ti ₃ Al based alloys. In: Darolia R, Levandovskii JJ et al., Structural Intermetallics. TMS, Warrendale, PA, pp. 19-31). O-phase-based alloys have the following advantages:

- high strength and plastic characteristics;

- low coefficient of thermal expansion;

- high characteristics of low-cycle and high-cycle fatigue;

- high heat-resistant properties and heat resistance at temperatures of 550 ... 700 ° C;

- in terms of specific heat-resistant characteristics (σ ₁₀₀ / ρ) they are superior to heat-resistant titanium alloys (IMI 834, Ti 1100) and INCO 718 heat-resistant alloy to temperatures of 550 ... 700 ° С.

However, for alloys based on technical grade Ti ₂ AlNb, the toughness and creep resistance are insufficient and must be increased (see Gogia AK, et al. 1998 Microstructure and mechanical properties of orthorhombic alloys in the Ti-Al-Nb system. Intermetallics 6, 741-8).

Known valve made of titanium, made with a separate head and rod connected by friction welding or diffusion welding. The head and the transition section to the rod are made of the first material containing titanium, for example, a conventional high-strength titanium alloy. The rod does not directly protrude into the combustion chamber and is made of a second material containing titanium, for example a heat-treated titanium alloy bar stock to improve ductility (WO 9605414 A1 PCT / US 95/10060). As a result, the valve manufacturing cost is significantly reduced compared to conventional titanium valves.

However, the temperature limit for titanium alloys (600 ° C) does not correspond to the maximum temperatures in the head of the exhaust valve; valves have a limited life. In addition, the connection of the valve head and the transition section with the rod by friction welding is well known, and is widely used for welding steel exhaust valves made of steel with different properties, and in this design does not increase the valve life.

A known method of manufacturing a valve, according to which a powder mixture is used for the manufacture of the valve, including titanium-based powder (pure titanium powder or titanium hydride, or a powder of a Ti-6Al-4V alloy, or Ti-6Al-4V-5TiB, or Al- type alloys V and Al-Sn-Zr-Mo-Nb-Si) and thermostable hardening powder in the form of ceramic particles TiB, TiB ₂ , TiC, Ti ₂ C, TiN, etc. The number of hardening particles in the powder mixture is 1% (volume) or more. The total content of ceramic particles and pores in the sintered preform is from 1 to 5%, volume. The powder mixture is compacted by compression using a mold and sintered. Then, using a number of deformation treatments, a valve blank is obtained (see EP 0997614 A2).

The disadvantages of this method of manufacturing a valve include:

- In metal composites reinforced with discrete (ceramic) particles, with a particle size of 1 to 40 μm, which do not form a strong bond with the matrix at the interfaces, in some cases, which do not agree on the parameters of the crystal lattice with the matrix material, the hardening mechanism is due mainly to Thus, due to the braking of the dislocation by discretely distributed particles, i.e. only partial realization of the possibilities of composite materials is manifested here.

- The irregular structure of the composite reinforcement for such poorly filled materials (up to 5% (volumetric) reinforcing particles and pores) causes an unregulated anisotropy of their physicomechanical properties.

- The formation of an unstable connection at the interface between the reinforcing particles and the matrix reduces their strength and fatigue properties. Areas of lack of adhesion to the surrounding matrix are predominant places for the initiation of cracks and fracture. During tensile deformation, reinforcing particles contribute to the formation of cavitation pores.

- A significant difference in the linear thermal expansion coefficient of the used reinforcing particles (TiB, TiB ₂ , TiC, Ti ₂ C, TiN, etc.) and matrix metals leads to a stress concentration at the matrix-particle interfaces and the appearance of cracks in composites working in thermal cycling conditions.

Known metallurgy of granules, combining solidification of the melt with a high crystallization rate in the form of spherical granules, and compacting them into billets with the achievement of a dense structure (see Anoshkin NF “Some aspects of the quality of heat-resistant and high-strength materials produced by the metallurgy of granules”, p.7 -13. / Borzetsovskaya K.M. et al. “The influence of compaction modes on the structure of granular heat-resistant titanium alloy VT25U”, pp. 424-429. Collection of articles. Metallurgy of granules. VILS, Moscow, 1986). Pellet metallurgy allows us to simultaneously solve the problem of obtaining materials with a new level of required properties and efficient production of high-quality billets.

Currently, the applicant is not aware of the manufacture of composite materials using the granular metallurgy method.

The closest in technical essence to the analogue of the invention is a valve of an internal combustion engine containing a cylindrical rod, a disk-shaped head and a transition section providing smooth conjugation of the rod and head made of heat-resistant titanium alloy, and a method for its manufacture, including the manufacture of a cylindrical valve blank, preheating of the workpiece, deformation processing of the cylindrical workpiece with obtaining the specified microstat in the valve blank hectures (patent RU 2244135 C2).

However, the valves of the proposed alloys obtained according to the method of manufacture declared in the prototype have significant disadvantages, namely:

- Instability of material properties. According to the state diagram of titanium-aluminum in prototype alloys with a content of 7.5 ... 12.5 wt.% Aluminum, an α ₂ phase (Ti ₃ Al) is released when the aluminum content exceeds 6.0 wt.%. The α ₂ phase (Ti ₃ Al) is initially released in the form of nano-sized inclusions, providing classical dispersion hardening. Studies have established that, upon completion of the precipitation of the α ₂ phase (≥50 hours at 600 ° C), the strength properties of the valve material reach a maximum, and then begin to decline. The decrease in the strength characteristics of the valve material occurs as a result of collective diffusion and growth of precipitations of the α ₂ phase, leading to embrittlement of the material.

- Relatively low resource of operation of the valve, and therefore the engine itself. The maximum duration of the prototype valve to brittle fatigue failure is not more than 100 hours, which is clearly insufficient. This fact is confirmed by the authors of patent RU 2244135 C2. The deformation processing of a part of a cylindrical billet related to the rod, provided by wedge-shaped rolling, as provided for in the valve manufacturing method, allows to obtain a combination of 3 types of microstructures: equiaxial, bimodal and lamellar, passing from one type to another from the surface to the center.

However, this combination of microstructures is retained only in the valve blank, since due to the limited possibilities of wedge rolling in terms of deformation for a heat-resistant titanium alloy, the diameter of the rolled section of the billet significantly exceeds the diameter of the valve stem and thin surface layers with equiaxed and bimodal microstructures are cut off during subsequent machining of the billet valve. As a result, only a lamellar microstructure with a grain size of up to 50 μm, which is not optimal for the valve stem, is stored in the valve stem.

The objective of the invention is to increase the reliability and service life of the engine valves with reduced mass and increase engine durability by ensuring the stability of the microstructure of the valve material and its operational properties. This achieves the technical result, which consists in improving the properties of the valve material, ensuring the long-term performance of the internal combustion engine valves in a wide range of operating temperatures in the valve (600-900 ° С): long-term strength at operating temperatures, creep resistance, fracture toughness, fatigue strength and normal module elasticity, allowing to produce valves from a composite material with predetermined properties, providing a reduction in the mass of valves relative to steel to 50%, necessary and sufficient heat resistance for engines for various purposes, the level of boost, including turbocharging and a resource.

The specified technical result is achieved by the fact that in the proposed light valve of an internal combustion engine of composite heat-resistant material based on titanium and its intermetallic compounds, including structural elements in the form of a cylindrical rod, a disk-shaped head and a smooth transition section between them, at least one of the structural the elements are prefabricated from structural compositions of spherical granules of heat-resistant materials based on titanium and / or its intermetallic compounds, consisting of three composites entom, and the 1st component is a granular matrix, the 2nd component is a granular reinforcing or plastic additive, and the 3rd component is a nanoscale thermostabilizing and thermo-strengthening powder additive from thermodynamically stable and resistant to the 1st and 2nd oxide components , carbides, nitrides and borides of metals and / or non-metals of the Periodic system of elements, with the following content of components of the composite material, vol.%:

- a matrix of granules of a fraction of 20-800 microns - 75-95;

- nanoscale additive fraction of 10-100 nm - 0.01-3.0;

- the addition of a hardening or plastic phase from granules of a fraction of 5-600 microns - the rest.

The specified technical result and the elimination of disadvantages in the present invention is also achieved by the fact that in the structural composition of spherical granules, as the first component, the granular matrix, granules of heat-resistant titanium alloy of pseudo-α- or (α + β) -phase composition are used, as 2 th component - the reinforcing phase used pellets intermetallic compound Ti ₂ Al (α ₂ -phase) or granules of intermetallic compound Ti ₂ AlNb (O-phase) or granules of intermetallic alloys based on the data, and as a third component, and USE nanoscale Thermally thermostabilizing additive powder and yttrium dioxide or aluminum oxide. This composite material provides an increase in the temperature regime of the valve to 650-700 ° C.

The specified technical result and the elimination of disadvantages in the present invention is also achieved by the fact that in the structural composition of spherical granules, as the first component, the granular matrix, granules of the intermetallic compound Ti ₃ Al (a ₂ phase) or granules of the intermetallic compound Ti ₂ AlNb (O -phase), or granules of alloys based on these intermetallic compounds, granules of a heat-resistant titanium alloy of pseudo-α- or (α + β) -phase composition were used as the 2nd component - plastic phase, and as the 3rd component and USE nanoscale Thermally thermostabilizing additive powder and yttrium dioxide or aluminum oxide, which increases the operation temperature of the valve up to 750 ° C.

The specified technical result and the elimination of disadvantages in the present invention is also achieved by the fact that in the structural composition of spherical granules, granules of the intermetallic compound Ti ₂ AlNb (O phase) or granules of the alloy based on the intermetallic compound Ti ₂ AlNb are used as the first component — the granular matrix (O-phase), granules of the TiAl intermetallic compound (γ-phase) or alloy granules based on this intermetallic compound were used as the 2nd component of the strengthening phase, and the 3rd component was used nanoscale thermostabilizing and heat-strengthening additive of yttrium dioxide or alumina powder, which provides an increase in the temperature regime of the valve to 800 ° C.

The specified technical result and the elimination of disadvantages in the present invention is also achieved by the fact that in the structural composition of spherical granules, granules of the intermetallic compound TiAl (γ-phase) or granules of an alloy based on the intermetallic compound TiAl (γ- phase), as a 2nd component - plastic granules used phase intermetallic compound Ti ₂ AlNb (O-phase) or an alloy granules on the basis of the intermetallic compound, and as a third component used in Thermally orazmernaya thermostabilizing additive powder and yttrium dioxide or aluminum oxide, which increases the operation temperature of the valve up to 900 ° C.

The specified technical result and the elimination of disadvantages in the present invention is also achieved by the fact that the structural element: the dish-shaped head, the transition section, providing a smooth connection of the rod and the head, and part of the rod to the junction, are made of composite heat-resistant material, and the rest of the rod is made of a titanium alloy of (α + β) -or β-phase composition, and valve structural elements are interconnected by diffusion welding, soldering, resistance welding, welding of three low or explosion. As a result, a reduction in the cost of manufacturing the valve is ensured under conditions of mass production without reducing its operational properties.

In the present invention, the aforementioned disadvantages are eliminated by creating a valve made of composite heat-resistant materials with various properties of heat resistance, mechanical strength and ductility, thermodynamically stable in the temperature range of 650 ... 900 ° C, providing increased reliability and reliability of valves with reduced weight for internal combustion engines various purposes and the level of forcing and, thereby, increasing the durability of engines.

For a more detailed confirmation and justification of the materiality of the features of the invention, “Lightweight valve of an internal combustion engine of composite heat-resistant materials”, see the section “Examples of the invention”.

The specified technical result and elimination of shortcomings in the proposed method for manufacturing a valve of an internal combustion engine from a composite heat-resistant material based on titanium and its intermetallic compounds, consisting of a cylindrical rod, a plate-shaped head and a smooth transition section between them, including obtaining composite material for a cylindrical valve blank, pre-heating the billet, deformation processing of the cylindrical billet with obtaining a predetermined stream in the billet rounds, it is achieved by the fact that the cylindrical valve blank is obtained from a mixture of matrix granules, additives and nanosized powder, which is collected with predetermined properties by selecting fractions, microstructures, chemical and phase compositions of the granules, filled into a cylindrical shape of a given diameter, form a structural composition of spherical granules when vibrating on the mold, vacuum and seal, and then compact in a gas bath at a temperature of 900-1300 ° C and a pressure of 100-250 MPa, after which the resulting cylindrical the preform is subjected to deformation processing by extruding to a predetermined size along the diameter of the cylindrical preform for the valve head when heated to the temperature of the subsequent deformation, after extruding the preform, the part of the preform corresponding to the valve stem is heated, and deformation processing is performed to obtain a predetermined diameter of the rod in the valve preform while maintaining in the rod of a previously defined structure, then part of the workpiece corresponding to the head and the smooth transition section is heated valve, deformation processing is performed by stamping to obtain a predetermined shape of the valve head, and then perform the final machining of the workpiece with the valve adjusting the valve to the desired dimensions and surface finish.

The specified technical result and the elimination of disadvantages in the proposed method for manufacturing a valve of an internal combustion engine is also achieved by the fact that for the manufacture of cylindrical valve blanks, a composite material is used, which is obtained by compacting the structural composition of spherical granules based on titanium and its intermetallic compounds with a phase composition:

- α, β, α ₂ , where (α and β) phases are the matrix,

- or α, β, α ₂ , where the (α ₂ ) -phase is a matrix,

- or α, β, B2, O, where (α and β) phases are the matrix,

- or α, β, B2, O, where (B2 and O) phases are the matrix,

- or α ₂ , O, B2, γ, where (α ₂ , O, B2) phases are the matrix,

- or α ₂ , O, B2, γ, where the (γ) -phase is a matrix providing the specified heat resistance properties of the valve material.

The specified technical result and the elimination of disadvantages in the proposed method of manufacturing a valve of an internal combustion engine is also achieved by the fact that the heating of a compact billet for extrusion is carried out depending on the matrix material in the following modes:

- a matrix of (α and β) -phase composition - 5-50 ° C below the temperature of the complete polymorphic transformation of the alloy;

- a matrix of (α ₂ ) -phase composition - 450-530 ° C below the melting point of the Ti ₃ Al intermetallic compound or alloys based on it;

- a matrix of (B2 and O) -phase composition - 190-340 ° C below the melting point of the Ti ₂ AlNb intermetallic compound or alloys based on it;

- a matrix of (γ) -phase composition - 60-220 ° C below the melting point of the TiAl intermetallic compound or alloys based on it;

while extrusion is carried out with a degree of deformation of at least 70%.

The specified technical result and the elimination of disadvantages in the proposed method of manufacturing a valve of an internal combustion engine is also achieved by the fact that the deformation processing of a part of a cylindrical billet related to the rod after extrusion is carried out by radial forging with preliminary heating to a temperature of 300-1100 ° C.

The specified technical result and the elimination of disadvantages in the proposed method of manufacturing a valve of an internal combustion engine is also achieved by the fact that the deformation processing of the part of the cylindrical billet related to the rod after extrusion is carried out by transverse wedge rolling, while the preliminary heating is carried out depending on the matrix material :

- a matrix of (α and β) -phase composition - 10-70 ° C below the temperature of the complete polymorphic transformation of the alloy;

- a matrix of (α ₂ ) -phase composition - 550-620 ° C below the melting point of the Ti ₃ Al intermetallic or alloys based on it;

- a matrix of (B2 and O) -phase composition — 280-420 ° C below the melting point of the Ti ₂ AlNb intermetallic compound or alloys based on it;

- a matrix of (γ) -phase composition is 260-310 ° C below the melting point of the TiAl intermetallic compound or alloys based on it.

The specified technical result and the elimination of shortcomings in the proposed method of manufacturing a valve of an internal combustion engine is also achieved by the fact that the heating of the part of the workpiece related to the head and the transition to the rod for stamping is carried out depending on the matrix material in the following modes:

- a matrix of (α and β) -phase composition — 50 ° C lower or higher than the temperature of the complete polymorphic transformation of the alloy;

- a matrix of (α ₂ ) -phase composition - 450-550 ° C below the melting point of the Ti ₃ Al intermetallic compound or alloys based on it;

- a matrix of (B2 and O) -phase composition — 270-480 ° C below the melting point of the Ti ₂ AlNb intermetallic compound or alloys based on it;

- a matrix of (γ) -phase composition - 140-400 ° C below the melting point of the TiAl intermetallic compound or alloys based on it.

The specified technical result and the elimination of shortcomings in the proposed method of manufacturing a valve of an internal combustion engine is also achieved by the fact that a single blank for the valve is assembled in a predetermined form from structural compositions of spherical granules, at least two compositions for the rod and head, with a smooth transition and mixing mixtures of each with the other in the transition of the head to the rod.

Thus, the inventive method of manufacturing a valve based on the use of deformation technologies. This allows you to get the valve of an internal combustion engine from a composite heat-resistant material based on titanium and its intermetallic compounds obtained by the method of granular metallurgy, while different types of composite material have a different level of properties that provide long-term thermal stability in the temperature range from 650 to 900 ° C, and corresponding to the conditions of mechanical and prolonged thermal loading of the valve in the internal combustion engine.

A more detailed confirmation and justification of the materiality of the features for the invention, “Method for manufacturing a valve of an internal combustion engine”, see “Examples of the invention”.

The invention is illustrated by drawings, where:

- figure 1 shows a General view of the internal combustion engine valve;

- figure 2 shows a General view of the internal combustion engine valve, made of 2 different materials;

- figure 3 shows the original cylindrical blank of composite material;

- figure 4 shows the workpiece after radial forging;

- figure 5 shows the billet of the valve of an internal combustion engine after stamping;

- figure 6 shows a photo of the collapsed valve prototype (patent RU 2244135) after 60 hours of operation in the engine;

- figure 7 shows a photo of the valve according to the invention after 300 hours of operation in the engine.

The following are examples of the invention.

The valve (figure 1) contains a rod 1 of constant diameter and a plate-shaped head 2, including a transition section 3, providing a smooth pairing of the rod and the head.

For the practical implementation of the invention and the production of a lightweight valve with the specified properties of heat resistance and reliability, 6 variants of composite materials based on heat-resistant titanium alloys of (α + β) -phase composition (VT 9), pseudo-α-phase composition (VT 18U), intermetallide were manufactured Ti ₃ Al and an alloy based on it, an alloy based on an intermetallic Ti ₂ AlNb, an intermetallic TiAl and an alloy based on it, and nanosized powders Y ₂ O ₃ and Al ₂ O ₃ . The chemical compositions of the composite materials are shown in Table 1. Table 2 shows the structural compositions of spherical granules for the made variants of composite materials, including the volume content of granules and nanosized powders, and their sizes. Moreover, the structural compositions of spherical granules in examples No. 1, 2, 3 and 4 provide the heat-resistant properties of the valve composite materials to temperatures of 650, 750, 800 and 900 ° C, respectively.

The manufacture of composite materials was carried out according to the well-known technology of granular metallurgy. The manufacture of granules of the starting components was carried out in a specialized installation.

Next, the following technological operations were carried out:

- the operation of separation of granules was carried out on the installation of sieving and magnetic separation of granules (UR and MS);

- after sieving the granules and their classification suitable granules were subjected to electrostatic separation at the SES installation;

- the mixing of nanosized powders Y ₂ O ₃ or Al ₂ O ₃ with the structural compositions of spherical granules was carried out in a planetary centrifugal mill;

- filling of the structural compositions of spherical granules into capsules with a diameter of 70 mm, the formation of structural compositions of spherical granules under vibrational influence on the capsule and their sealing was carried out at the filling and sealing capsules (UZGK) installation. To ensure good conditions for diffusion coalescence of the granules, they were thermally degassed and surface activated by heating the granules before filling into capsules in vacuum (~ 10-5 torr) to a temperature of 500 ° C. Capsule sealing was carried out by electron beam welding of the receiving hole;

- the brewed capsule was subjected to gas-static compaction in a gas bath at a temperature of 950 ° C (for examples No. 1, 5 and 6) and 1150 ... 1325 ° C (for examples No. 2-4) and pressures up to 220 MPa.

- the resulting compact blanks were extruded into rods with a diameter of 20 mm;

- from the obtained rods of composite materials were made: cylindrical blanks 6 (figure 3) for the subsequent manufacture of valves and samples for testing the mechanical properties of composite materials.

Table 1 Chemical compositions of alloys to obtain new composite heat-resistant materials Alloy grade The content of alloying elements, wt.% Al Mo Zr No V Ti Sn W Si FROM Examples No. 1, 5 and 6 BT 9 (α + β) 5.8-7.0 2.8-3.8 1.0-2.0 - - Ost. - - 0.2-0.35 - Ti ₃ Al (α ₂ phase) * 25.0 - - - Ost. - - - - Example No. 2 Alloy Based Ti ₃ Al (α ₂ phase) * 24.0 - - 11.0 - Ost. - - - - VT 18U (pseudo-α) 6.2-7.3 0.4-1.0 3.5-4.5 0.5-1.5 - Ost. 2.0-3.0 - 0.15 - Example No. 3 Alloy Based Ti ₂ AlNb (O phase) * 23 - 0.6 22.7 1,1 Ost. - - 0.14 0.3 TiAl (γ phase) * 48 - - - Ost. - - - Example No. 4 Alloy Based TiAl (γ phase) * 46 - - 5,0 - Ost. - 1,0 - - Alloy Based Ti ₂ AlNb (O phase) * 23 - 0.6 22.7 1,1 Ost. - - 0.14 0.3 *) - chemical composition in at.%

table 2 Compositions of structural compositions of spherical granules for the manufacture of valve samples from new composite heat-resistant materials In accordance with the invention Compositions of structural compositions of spherical granules Example Example Example Example Example Example No. 1 Number 2 Number 3 Number 4 Number 5 Number 6 Matrix VT 9 Alloy Based Alloy Based Alloy Based VT 9 VT 9 (α + β) Ti ₃ Al (α ₂ phase) Ti ₂ AlNb (O phase) TiAl (γ phase) (α + β) (α + β) The volume content of granules,% 80 83 86 90 98 70 Granule size (pre.), Microns 800 500 300 twenty 10 900 Additives Ti ₃ Al VT 18U TiAl (γ phase) * Alloy Based Ti ₃ Al Ti ₃ Al (α ₂ phase) (pseudo-α) Ti ₂ AlNb (O phase) * (α ₂ phase) (α ₂ phase) The volume content of granules,% 19.7 16.9 13.95 9.99 1,995 26.8 Granule size (pre.), Microns 600 200 125 10 4.0 370 Nanopowders Y ₂ O ₃ Y ₂ O ₃ Al ₂ O ₃ Al ₂ O ₃ Y ₂ O ₃ Y ₂ O ₃ Volume content,% 0.3 0.1 0.05 0.01 0.005 3.2 Powder Size (pre.) Nm one hundred 70 thirty 10 5 105

At the first stage of deformation processing from a cylindrical workpiece by radial forging on a rotary forging machine company "NMR" (Germany) received a workpiece of intermediate form 7 (Fig.4) for subsequent stamping of the valve head. The cylindrical billet was preliminarily heated by induction to a temperature of 500 ° C (for examples No. 1, 5 and 6), 650 ° C (for examples No. 2-3) and 750 ° C (for example No. 4). As a result of processing on a rotary forging machine, a valve stem was formed with a diameter corresponding to the diameter of the finished valve stem with an allowance of 0.15 mm for subsequent machining.

It was experimentally established that heating cylindrical billets to temperatures of 500, 650 and 750 ° C provides reliable radial forging of these composite materials. At lower heating temperatures, the radial forging process is delayed in time; heating to higher temperatures causes the formation of an undesirable alpha layer on the surface of the workpieces.

Hot stamping of the valve heads was carried out on a mechanical crank press.

Heating for stamping was carried out by the induction method only of that part of the workpiece that was subjected to deformation during the shaping of the valve head and the section of transition to the rod. After heating to a predetermined temperature, the valve head was stamped.

Stamping was carried out at temperatures:

- 50 ° C lower or higher than the temperature of the complete polymorphic transformation (T _PP ) for alloy VT 9 (for examples No. 1, 5 and 6);

- 450-550 ° C below the melting point of the alloy based on the Ti ₃ Al intermetallic compound (for example, No. 2);

- 270-480 ° C below the melting point of the alloy based on intermetallic Ti ₂ AlNb (for example No. 3);

- 140-400 ° C below the melting point of the alloy based on the TiAl intermetallic compound (for example, No. 4).

In this case, by means of stamping, a valve-shaped valve head 2 was formed with a smooth transition section 3 into the rod 1. The valve blank is shown in Fig. 5.

It was experimentally established that such temperature conditions of heating for stamping provide high quality shaping of the valve head and the section of transition to the rod. When the workpiece is overheated for stamping, that is, heating it above the specified temperatures, an unwanted coarsening of the microstructure in the valve head occurs; with insufficient heating of the workpiece, that is, below the indicated temperatures, the valve head is not stamped.

Performing deformation processing according to the declared modes in the manufacture of ICE valves from composite materials in accordance with examples No. 1-6 provides obtaining the mechanical properties of composite materials in ICE valves, shown in table 3.

An analysis of the data obtained by the results of metallographic and structural-phase studies, tests of the physicomechanical properties of composite materials and tests of manufactured valve samples (see table 3) showed the following:

1. Valves made of composite materials with the claimed volumetric content of components according to examples of the invention No. 1-4 demonstrated high strength properties at room temperature and heat-resistant properties at temperatures of 650-900 ° C, increased modulus of elasticity, high fatigue strength both at room temperature and and at maximum operating temperatures for valves, long-term thermal stability and technological plasticity, providing the required deformation processing.

2. With an increased volume content of matrix granules (example No. 5), a valve made of this composite material had worse properties: density, long-term strength, and creep limit at a temperature of 650 ° C, as well as elastic modulus and specific elastic modulus in comparison with the valve of example No. 1.

3. With a reduced volume content of matrix granules (example No. 6), a valve made of this composite material had the worst properties: ultimate tensile strength and fatigue strength at a temperature of 650 ° C, in comparison with the valve according to example No. 1.

4. Comparison of the properties of the valve made of composite material according to example No. 1 with the properties of the valve-prototype of heat-resistant titanium alloy hardened by intermetallic α ₂ -phase (Ti ₃ Al) according to patent RU 2244135, shows a significant superiority of the valve according to example No. 1 in terms of heat-resistant properties: tensile strength (more than 3 times) and creep strength (more than 55%) at a temperature of 650 ° C above the prototype valve. These properties are confirmed by the results of accelerated motor tests of a valve made of composite material according to example No. 1 for reliability and durability (OST 37.004.004-74) with a duration of 300 hours without destruction, which is equivalent to a vehicle mileage of 180.0 thousand km under operating conditions engine. At the same time, the material of the prototype valve was embrittled when holding for 60-100 hours at a temperature of 600 ° C, which caused fatigue failure of the valve. Figures 6 and 7 show photos of valve samples according to patent RU 2244135 (collapsed after 60 hours) and from a composite (operating hours 300 hours without breaking). The obtained properties of the composite material ensure reliable operation of engine valves during their long-term operation.

Table 3 Test Results for Composite Heat Resistant Valves Composite Material Properties In accordance with the invention Example Example Example Example Example Example Prototype No. 1 Number 2 Number 3 Number 4 Number 5 Number 6 by patent RU 2244135 Density (ρ), kg / dm ³ 4.42 4.23 5,0 4.26 4.46 4.36 4.38 Tensile Strength (σ _V ), MPa: 20 ° C 1215 995 1045 885 1150 1050 1100 650 ° C 675 785 - - 620 585 535 750 ° C - 585 685 - - 800 ° C - 530 785 - - 900 ° C - - - 680 - - - Yield Strength (σ _0.2 ), MPa: 20 ° C 1060 840 955 800 1000 920 - 650 ° C 527 670 - - 480 440 450 750 ° C - 510 525 - - - - 800 ° C - - 470 590 - - - 900 ° C - - - 530 - - - Modulus of elasticity (E), GPa: 20 ° C 119 142.5 127 160 107 125 120 Ultimate Strength (σ ₁₀₀ ), MPa: 650 ° C > 190 - - - <100 160 <60 750 ° C - > 210 - - - - - 800 ° C - - > 240 - - - - 900 ° C - - - > 220 - - - Creep strength (σ _{0.2 / 100} ), MPa: 650 ° C > 125 - - - <95 - <80 750 ° C - > 110 - - - - - 800 ° C - - > 90 - - - 900 ° C - - - > 75 - - - Fatigue strength (σ _-1 ), MPa: 20 ° C 670 785 855 755 - 580 - 650 ° C 390 545 - - - 310 - 750 ° C - 300 397 - - - - 800 ° C - - 330 470 - - 900 ° C - - - 380 - - - Specific modulus of elasticity (E / ρ), GPa / kg / dm ³ : 20 ° C 27 33.7 25,4 37.6 24.0 28.7 27.4 Specific Fatigue Strength (σ _-1 / ρ), 151.5 185.5 171 177 - 133 - MPa / kg / dm ³ : 20 ° C 650 ° C 88.0 128.8 - - - 71 - 750 ° C - 71.0 80 - - - - 800 ° C - - 66 110 - - - 900 ° C - - - 89 - - - Duration of bench tests of valves, engine hours 300 - - - - - 60 (collapsed)

Claims (14)

1. Valve of an internal combustion engine made of composite heat-resistant material, comprising a cylindrical rod, a disk-shaped head and a smooth transition section between them, characterized in that at least the said head, transition section and part of the rod are made of heat-resistant granular metallurgy based on titanium or its intermetallic compounds, consisting of spherical matrix granules and a hardening or plastic additive, as well as a nanoscale heat-hardening powder additive of those dynamically stable and material-resistant matrix granules and to a hardening or plastic additive in the form of oxides, carbides, nitrides or borides of metals and / or non-metals, with the following components, vol. %:
a matrix of granules of a fraction of 20-800 microns 75-95 nanoscale additive of a fraction of 10-100 nm 0.01-3.0 hardening or plastic additive from granules of fraction 5-600 microns rest 2. The valve according to claim 1, characterized in that the said head, transition section and part of the rod are connected to the rest of the rod by diffusion welding, soldering, resistance welding, friction welding or explosion. 3. The valve according to claim 1, characterized in that the material as a matrix contains spherical granules of heat-resistant pseudo-α- or (α + β) -titanium alloy, as a hardening or plastic phase contains spherical granules of the intermetallic compound Ti ₃ Al ( α ₂ -phase) or intermetallic compound Ti ₂ AlNb (O-phase), or alloys based on them, and yttrium dioxide or alumina powder as nanoscale thermostabilizing and heat-strengthening additives. 4. The valve according to claim 1, characterized in that the material as a matrix contains spherical granules of the Ti ₃ Al intermetallic compound (α ₂ phase) or the Ti ₂ AlNb intermetallic compound (O phase), or alloys based on them, as the hardening or plastic phase contains spherical granules of heat-resistant pseudo-α- or (α + β) -titanium alloy, and yttrium dioxide or alumina powder is used as a nanoscale thermostabilizing and heat-hardening additive. 5. The valve according to claim 1, characterized in that the material as a matrix contains spherical granules of the Ti ₂ AlNb intermetallic compound (O phase) or an alloy based on it, contains spherical granules of the TiAl intermetallic compound (γ- phase) or an alloy based on it, and as a nanoscale thermostabilizing and heat-strengthening additives - yttrium dioxide or alumina powder. 6. The valve according to claim 1, characterized in that the material as a matrix contains spherical granules of an intermetallic compound TiAl (γ-phase) or an alloy based on it, as a hardening or plastic phase contains spherical granules of an intermetallic compound Ti ₂ AlNb (O- phase) or an alloy based on it, and as a nanoscale thermostabilizing and heat-strengthening additives - yttrium dioxide or alumina powder. 7. The valve according to claim 1 or 2, characterized in that the rest of the shaft is made of (α + β) - or P-titanium alloy. 8. A method of manufacturing a valve of an internal combustion engine from a composite heat-resistant material containing a cylindrical rod, a disk-shaped head and a smooth transition section between them, including obtaining a cylindrical valve preform from composite material, pre-heating the preform and deforming the preform to obtain a given structure, different the fact that the cylindrical billet of the valve is obtained from a mixture of spherical granules of the matrix and reinforcing or plastic ext wafers made from heat-resistant materials based on titanium or its intermetallic compounds, as well as nanoscale heat-strengthening powder additives from thermodynamically stable and material-resistant matrix granules and to a strengthening or plastic additive in the form of oxides, carbides, nitrides or borides of metals and / or non-metals by filling the mixture into cylindrical shape of a given diameter, vibration effects on the shape, evacuation, sealing and compaction in a gas bath at a temperature of 900-1300 ° C and a pressure of 100-250 MPa, deformation processing the workpiece is carried out by extruding to a predetermined size along the diameter of the cylindrical workpiece for the valve head when heated to a temperature of subsequent deformation, while after extruding the workpiece, part of the workpiece corresponding to the valve stem is heated, and deformation processing is performed to obtain the specified diameter of the rod in the valve workpiece while maintaining in the rod of a given structure, then the part of the workpiece corresponding to the head and the smooth transition section of the valve is heated, deformation stamping processing to obtain a predetermined shape of the valve head, after which the final machining of the valve blank is carried out with bringing to the required dimensions and surface finish of the finished valve. 9. A method according to claim 8, characterized in that to ensure a predetermined high-temperature strength of the valve material comprises a matrix (α and β) phase, the additive - α ₂ -phase or matrix (α ₂₎ phase, additive - (α and β) -phases or matrix of (α and β) -phase, additive - (B2 and O) -phases or matrix (B2 and O) -phases, additive - (α and β) -phases or matrix (α ₂ , O, B2) -phase, the additive is the γ-phase or the matrix of the γ-phase, the additive is (α ₂ , O, B2) -phase. 10. The method according to claim 8, characterized in that the extrusion is carried out with a degree of deformation of at least 70% when the billet is heated to a temperature of 5-50 ° C below the temperature of the complete polymorphic transformation of the alloy in a matrix containing (α and β) phases, or to a temperature of 450-530 ° C below the melting point of the Ti ₂ Al intermetallic or alloys based on it with a matrix containing the (α ₂ ) phase, or to a temperature of 190-340 ° C below the melting point of the Ti ₂ AlNb intermetallic or alloys based on it with a matrix containing (B2 and O) phases, or to a temperature of 60-220 ° C below the melting point Ia or intermetallic compound TiAl-based alloys with a matrix comprising (γ) phase. 11. The method according to claim 8, characterized in that the deformation processing of the part of the cylindrical billet related to the rod, carried out after extrusion, is carried out by radial forging with preliminary heating to a temperature of 300-1100 ° C. 12. The method according to claim 8, characterized in that the deformation processing of the part of the cylindrical billet related to the rod, carried out after extrusion, is carried out by cross-wedge rolling when heated to a temperature of 10-70 ° C below the temperature of the complete polymorphic transformation of the alloy with the matrix containing (α and β) phases, or to a temperature of 550-620 ° C below the melting point of the Ti ₃ Al intermetallic or alloys based on it with a matrix containing the (α ₂ ) phase, or to a temperature of 280-420 ° C below the melting point of the Ti ₂ AlNb intermetallic compound or alloys on its basis, with a matrix containing (B2 and O) phases, or to a temperature of 260-310 ° C below the melting point of the TiAl intermetallic compound or alloys based on it with a matrix containing (γ) phase. 13. The method according to claim 8, characterized in that the stamping part of the preform related to the said head and the transition section is heated to a temperature of 50 ° C lower or higher than the temperature of the complete polymorphic transformation of the alloy with a matrix containing (α and β) -phase, or to a temperature of 450-550 ° C below the melting point of the Ti ₃ Al intermetallic or alloys based on it with a matrix containing the (α ₂ ) phase, or to a temperature of 270-480 ° C below the melting point of the Ti ₂ intermetallic AlNb or alloys based on it with a matrix containing (B2 and O) phases, or to tempera ry at 140-400 ° C below the melting point of TiAl intermetallic compound or alloys on its basis with a matrix comprising (γ) phase. 14. A method according to any one of claims 8 to 13, characterized in that the cylindrical valve blank is obtained from at least two mixtures of granules for the rod and for the head of the dish-shaped form with a section of smooth transition between them when mixing said mixture of granules at the said transition section.

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