Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C9/00—Alloys based on copper
  • C22C9/06—Alloys based on copper with nickel or cobalt as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/08—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper or alloys based thereon

Definitions

• This invention relates to copper base alloys, and in particular to copper- nickel-silicon base alloys.
• Copper-nickei-silicon base alloys are widely used for the production of high strength, electrically conductive parts such as connectors and lead frames.
• C7025 developed by Olin Corporation, is an important example of a copper-nickel-silicon base alloy that provides good mechanical ⁇ yield strength 95 ksi - 110 ksi) and good electrical properties ⁇ 35% iACS) . See U.S. Patent Nos. 4,594,221 and 4,728,372, incorporated herein by reference.
• C7035 a cobalt modified copper, nickel, silicon alloy
• Olin Corporation and Wieland Werke which can provide even better mechanical (yield strength 100 ksi - 130 ksi) and electrical properties (40-55% IACS).
• Yield strength 100 ksi - 130 ksi yield strength 100 ksi - 130 ksi
• electrical properties 40-55% IACS.
• Formability is typically evaluated by a bend test where copper strips are bent 90° around a mandrel of known radius.
• a roller bend test employs a roller to form the strip around the mandrel.
• a v-block test uses the mandrel to push the strip into an open die, forcing it to conform to the radius of the mandrel.
• the minimum bend radius (mbr) as a function of strip thickness (t) is then reported as mbr/t.
• the minimum bend radius is the smallest radius mandrel around which a strip can be bent without cracks visible at a magnification of 10x to 2Ox.
• mbr/t is reported for both good way bends, defined as the bend axis is normal to the rolling direction, and for bad way bends, defined as the bend axis is parallel to the rolling direction.
• An mbr/t of up to 4 t for both good way bends and bad way bends is deemed to constitute good formability. More preferred is an mbr/t of up to 2.
• IACS International Annealed Copper Standard that assigns "pure” copper a conductivity value of 100% IACS at 20° C Throughout this disclosure, all electrical and mechanical testing is performed at room temperature, nominally 20° C, unless otherwise specified. The qualifying expression "about” indicates that exactitude is not required and should be interpreted as +/-10% of a recited value.
• Strength is usually measured as yield strength.
• a high strength copper alloy has a yield strength in excess of 95 ksi (655.1 MPa) and preferably in excess of 110 ksi (758.5 MPa).
• a combination of strength and conductivity for a given temper will be more important than either strength or conductivity viewed alone.
• Ductility can be measured by elongation.
• One measure of elongation is
• A10 elongation which is the permanent extension of the gauge length after fracture, expressed as a percentage of the originai gauge length L 0 where L 0 is taken equal to 10 mm.
• Acceptable resistance to stress relaxation is viewed as at least 70% of an imparted stress remaining after a test sample is exposed to a temperature of 150° C for 3000 hours and at least 90% of an imparted stress remaining after a test sample is exposed to a temperature of 105° C for 1000 hours.
• Stress relaxation may also be measured by a lift-off method as described in ASTM (American Society for Testing and Materials) Standard E328-86.
• ASTM American Society for Testing and Materials
• This test measures the reduction in stress in a copper alloy sample held at fixed strain for times up to 3000 hours.
• the technique consists of constraining the free end of a cantilever beam to a fixed deflection and measuring the load exerted by the beam on the constraint as a function of time at temperature. This is accomplished by securing the cantilever beam test sample in a specially designed test rack.
• the standard test condition is to load the cantilever beam to 80% of the room temperature 0.2% offset yield strength.
• the initial stress is reduced until the deflection is less than 0.2 inch and the load is recalculated.
• the test procedure is to load the cantilever beam to the calculated load value, adjust a threaded screw in the test rack to maintain the deflection, and locking the threaded screw in place with a nut.
• the toad required to lift the cantilever beam from the threaded screw is the initial load.
• the test rack is placed in a furnace set to a desired test temperature. The test rack is periodically removed, allowed to cool to room temperature, and the load required to lift the cantilever beam from the threaded screw is measured.
• the percent stress remaining at the selected log times is calculated and the data are plotted on semi-log graph paper with stress remaining on the ordinate (vertical) and log time on the abscissa (horizontal). A straight line is fitted through the data using a linear regression technique. Interpolation and extrapolation are used to produce stress remaining values at 1 , 1000, 3000, and 100,000 hours.
• the resistance to stress relaxation is orientation sensitive and may be reported in the longitudinal (L) direction where 0° testing is conducted with the long dimension of the test sample in the direction of strip rolling and the deflection of the test sample is parallel to the strip rolling direction.
• the resistance to stress relaxation may be reported in the transverse (T) direction where 90° testing is conducted with the long dimension of the test sample perpendicular to the strip rolling direction and the deflection of the test sample is perpendicular to the strip rolling direction.
• Table 1 shows the mechanical and electrical properties of some of the commerciaily available copper alloys of which the inventors are aware:
• One aspect of the present invention is an age-hardening copper-nickel- silicon base alloy that can be processed to make a commercially useful strip product for use in electrical connectors and interconnections for the automotive and multimedia industries, in particular, and for any other applications requiring high yield strength and moderately high electrical conductivity in a strip, plate, wire or casting.
• Another aspect of the present invention is a processing method to make a commercially useful strip product for use in electrical connectors and interconnections for the automotive and multimedia industries and any other applications requiring high yield strength and moderately high electrical conductivity.
• a copper-nickel-silicon base alloy having an improved combination of yield strength and electrical conductivity that consists essentially of between about 1.0 and about 6.0 weight percent Ni, up to about 3.0 weight percent Co, between about 0.5 and about 2.0 weight percent Si 1 between about 0.01 and about 0.5 weight percent Mg, up to about 1.0 weight percent Cr, up to about 1.0 weight percent Sn 1 and up to about 1.0 weight percent Mn, the balance being copper and impurities.
• This alloy is processed to have a yield strength of at least about 137 ksi, and an electrical conductivity of at least about 32% IACS.
• a copper base alloy having an improved combination of yield strength and electrical conductivity that consists essentially of: between about 3.0 and about 5.0 weight percent Ni; up to about 2.0 weight percent Co; between about 0.7 and about 1.5 weight percent Si; between about 0.03 and about 0.25 weight percent Mg; up to about 0.6 weight percent Cr; up to about 1.0 weight percent Sn, and up to about 1.0 weight percent Mn, the balance being copper and impurities.
• This alloy is processed to have a yieid strength of at least about 137 ksi, and an electrical conductivity of at least about 32% IACS.
• a copper-nickel-silicon base alloy having an improved combination of yield strength and electrical conductivity that consists essentially of: between about 3.5 and about 3.9 weight percent Ni; between about 0.8 and about 1.0 weight percent Co; between about 1.0 and about 1.2 weight percent Si; between about 0.05 and about 0.15 weight percent Mg; up to about 0.1 weight percent Cr; up to about 1.0 weight percent Sn, and up to about 1.0 weight percent Mn, the balance being copper and impurities.
• This alioy is processed to have a yield strength of at least about 137 ksi, and an electrical conductivity of at least about 32% IACS.
• the alloys are preferably processed to have a yield strength of at least about 137 ksi, and an electrical conductivity of at least about 38% IACS, more preferably to have a yield strength of at least about 143 ksi, and an electrical conductivity of at least about 37% IACS, and most preferably to have a yield strength of at least about 157 ksi, and an electrical conductivity of at least about 32% !ACS.
• the ratio of (Ni+Co)/(Si-Cr/5) is preferably between about 3 and about 7, and more preferably between about 3.5 and about 5.0.
• the Ratio of Ni/Co is preferably between about 3 and about 5.
• the alloys and processing methods of the various embodiments provide copper base alloys having an improved combination of yield strength and electrical conductivity, and preferably stress relaxation resistance as well.
• the alloys have higher strength and greater resistance to stress relaxation than previously achieved with Cu- Ni-Si alloys, while maintaining reasonable levels of conductivity.
• Fig. 1 is a flow chart of the treatment of the alloys in Example 1 ;
• Fig. 2 is a flow chart of the treatment of the alloys in Example 2;
• Fig. 3 is a flow chart of the treatment of the alloys in Example 3.
• Fig. 4 is a graph of the yield strength versus conductivity for the alloys of
• Fig. 5 is a graph of yield strength versus bend formability (MBR/t) for the alloys of Example 3;
• Fig. 6 is a flow chart of the treatment of the alloys of Example 4;
• Fig. 7 is a graph of yield strength versus conductivity for the alloys of
• Fig. 8 is a graph of yield strength versus bend formability (MBR/t) for the alloys of Table 5 processed by SA-CR-age-CR-age process of Example 4;
• Fig. 9 is flow chart of the treatment of the alloys in Example 5.
• Fig. 10 is a graph of yield strength vs Ni/Co ratio for alloys without chromium having similar alloying ievels of Example 5;
• FIG. 11 is flow chart of the treatment of the alioys in Example 6;
• Fig. 12 is a flow chart of the treatment of the alloys in Example 7.
• Fig. 13 is a graph showing the effect of stoichiometric ratio on yield strength in copper-nickel-chromium-silicon alloys from Example 7;
• Fig. 14 is a graph showing the effect of stoichiometric ratio on yield strength in copper-nickel-cobalt-silicon alioys from Example 7;
• Fig. 15 is a graph showing the effect of effect of stoichiometric ratio on yield strength in copper-nickel-chromium-cobalt-silicon alloys from Example 7;
• Fig. 16 is a graph showing the effect of stoichiometric ratio on eiectrical conductivity in copper-nickel-chromium-silicon alloys from Example 7;
• Fig. 17 is a graph showing the effect of stoichiometric ratio on electrical conductivity in copper-nickel-cobalt-silicon alloys from Example 7;
• Fig. 18 is a graph showing the effect of stoichiometric ratio on electrical conductivity in copper-nickel-chromium-cobalt-silicon alloys from Example 7;
• Fig. 19 is a flow chart of the treatment of the alloys in Example 8;
• Fig. 20 is a graph showing the effect of stoichiometric ratio on %!ACS in
• Fig. 21 is a graph showing the effect of stoichiometric ratio on yield strength in Example 8 alloys processed by the SA-CR-age-CR-age approach with 475°C/300°C ages;
• Fig. 22 is a flow chart of the treatment of the alloys in Example 9
• Fig. 23 is a schematic diagram of tapered edge hot rolling specimen
• Fig. 26B is a photograph of the Result from tool wear test of Cr- containing alloy RN834062;
• Fig. 27 is a flow chart of the treatment of the alloys in Example 10.
• Fig. 28 is a graph showing the effect of stoichiometric ratio on %IACS in
• Fig. 29 is a graph showing the effect of stoichiometric ratio on yield strength in Example 8 and Example 10 (low Cr and Mn) alloys processed by the SA-CR-age- CR-age approach with 475°C/300°C ages;
• Fig. 30 is a flow chart of the treatment of the alloys in Example 11 ;
• Fig. 33 is a flow chart of the treatment of the alloys in Example 14.
• Fig. 37 is a graph of %IACS versus yield strength for alloys and processes of Examples 13, 14, 15, and 16. DETAILED DESCRIPTION
• the alloys of the preferred embodiment of the present invention have an improved combination of yield strength and electrical conductivity, good stress relaxation resistance, along with modest levels of bendability, consist essentially of from about 1.0 to about 6.0 weight percent nickel, from about 0.5 to about 2.0 weight percent silicon, from 0.0 to about 3.0 weight percent cobalt, from about 0.01 to about 0.5 weight percent magnesium, from 0.0 to about 1.0 weight percent chromium, and from 0.0 to about 1.0 weight percent of each of tin and manganese, the balance of the alioy being copper and impurities.
• the alloy consists essentially of from about 3.0 to about 5.0 weight percent nickel, from about 0.7 and about 1.5 weight percent silicon, from 0.0 to about 2.0 weight percent cobalt, from about 0.03 to about 0.25 weight percent magnesium, from about 0.0 to about 0.6% weight percent chromium, and from 0.0 to 1.0 weight percent of each of tin and manganese, the balance being copper and impurities.
• an optimum level of yield strength and electrical conductivity is needed, e.g.
• the most preferred alloy ranges are from about 3.5 to about 3.9 weight percent nickel; from about 1.0 to about 1.2 weight percent silicon; from about 0.8 to about 1.0 weight percent cobalt, from about 0.05 to about 0.15 weight percent magnesium, from 0 to about 0.1 weight percent chromium, and from 0.0 to about 1.0 weight percent of each of tin and manganese, the balance being copper and impurities.
• excessive coarse second phases are present when alloying elements are substantially beyond the indicated upper limits.
• Magnesium generally increases stress relaxation resistance and softening resistance in the finished products; it also increases softening resistance during in- process aging annealing heat treatments.
• Sn When present at low levels, Sn generally provides solid solution strengthening and also increases softening resistance during in-process aging annealing heat treatments, without excessively harming conductivity.
• Low levels of Mn generally improve bend formability, although with a loss of conductivity.
• the preferred embodiment of the process of the present invention comprises melting and casting; hot rolling (preferably from 750° to 1050 0 C), optional milling to remove oxide, and an optional homogenizat ⁇ on or intermediate bell anneal, cold rolling to a convenient gauge for solutionizing, solution annealing treatment (preferably at 800° - 1050 0 C for 10 seconds to one hour) followed by a quench or rapid cool to ambient temperature to obtain an electrical conductivity of less than about 20% IACS (11.6 MS/m) and an equiaxed grain size of about 5 - 20 ⁇ m; a 0 to 75% cold rolling reduction in thickness; an age hardening anneal (preferably at 300 - 600 0 C from 10 minutes to 10 hours); and optionally a further cold rolling 10 to 75% reduction in thickness to finish gauge; and second age hardening anneal (preferably at 250 to 500 0 C for 10 minutes to 10 hours).
• hot rolling preferably from 750° to 1050 0 C
• an optional homogenizat ⁇ on or intermediate bell anneal cold rolling to
• the preferred scheme to result in alloy with a yield strength of at least about 140 ksi, and a conductivity of at least about 30% IACS conductivity involves solutionizing at about 900° to 1000 0 C, cold rolling by about 25%, aging at about 450° - 500 0 C for 3 - 9 hours, cold rolling by about 20 - 25% to finish gauge, and aging 300° - 350 0 C for 3 - 9 hours.
• Fig. 1 is a flow chart of the process of this Example 1. After soaking two hours at 900 0 C they were hot rolled in three passes to 1.1" (1.6" / 1.35" / 1.1"), reheated at 900 0 C for 10 minutes, and further hot rolled in three passes to 0.50" (0.9" / 0.7" / 0.5"), followed by a water quench, followed by a homogenization or over-aging anneal at 590° for 6 hours.
• the alloys were cold rolled to 0.012" and solution heat treated in a fiuidized bed furnace for the time and temperature listed in Table 2. Time and temperature were selected to achieve approximately constant grain size. The alloys were then subjected to an aging anneal of 400° to 500 0 C for 3 hours, designed to increase strength and conductivity. The alloys were then coid rolled 25% to 0.009" and aged at 300° to 400 0 C for 4 hours. Properties measured after the second age anneal are presented in Table 3. The data indicate that yield strength increases with increasing alloying levels in the ternary alloys J994 through J999, from 127 to 141 ksi yield strength when Si levels range from 0.8 to 1.3%, respectively.
• Ni/Co ratio of about 3 leads to a higher strength than a Nt/Co ratio of 1 (K001 and K003), particularly at the higher Si level.
• Mn alloys K011 and K012 show evidence that Mn substitution for Ni improves the strength/bend properties, but at a significant loss of conductivity. Sn appears to provide solid solution strengthening, when comparing J994 to K036 and K037.
• Fig. 2 is a flow chart of the process of this Example 2. Subsequently the alloys were cold rolled 25 % to 0.009" then subjected to an aging anneal of 400° to 500 0 C for 3 hours. After an additional cold reduction of 22% to 0.007", samples were aged annealed at temperatures of 300° to 400 0 C for 3 hours. Properties from representative conditions are listed in Table 4. Bend properties in many cases are somewhat better at similar strengths than the process in Example 1. Co (K003 and K004) and Sn (K037) additions provide the highest strength increase of the alloys in this example.
• the alloys were then cold rolled to 0.012" and solution heat treated in a fluidized bed furnace for 60 seconds at the temperatures listed in Table 5. The temperature was selected to maintain a fairly constant grain size. Alloys were then subjected to an aging anneal of 400° to 500 0 C for 3 hours, designed to increase strength and conductivity. The alloys were then cold rolled 25% to 0.009" and aged at 300° to 400 0 C for 4 hours. Properties measured after the second age anneal are presented in Table 6. From this data set, it can be observed that additions to a base Alloy of Cu-Ni-Si of Co (K068), Cr (K072), or both Co and Cr (K070) achieve the best combinations of strength, conductivity and bend formability.
• the bend formability data indicates that K068 and K070 which both contain Co have the best formability at higher strength. Yield strength is plotted against conductivity in Figure 7, and against bend formability in Figure 8. The values for alloys K068, K070 and K072 are noted.
• Alloys were then subjected to an aging anneal of 450° to 500 0 C for 3 hours, designed to increase strength and conductivity.
• the alloys were then cold rolled 25% to 0.009" and aged at 300 to 400 0 C for 4 hours.
• Properties measured after the second age anneal for the process with a 475°C first age and 300 0 C second age are presented in Table 9.
• yield strength values tend to increase with higher alloying content.
• the plots of yield strength vs Ni/Co ratio in Figure 10 illustrate this, with the exception of K085, which has a higher Si level than K083 and K084.
• the Co-and-Cr-containing alloys, K086 to K094, were not as sensitive to overall alloying levels and Ni/Co ratio as the Co-only alloys.
• the Cr-only alloys (K095 to K097) also had comparable properties to the other alloy types.
• the alloys of Table 8 were solution heat treated in a fluidized bed furnace 60 seconds at the temperature listed in Table 8. Subsequently the alloys were cold rolled 25 % to 0.009" then subjected to an aging annea! of 450 to 500 0 C for 3 hours. After an additional cold reduction of 22% to 0.007", samples were aged annealed at temperatures of 300 to 400 0 C for 3 hours. Properties from samples given first and second ages at 450 0 C and 300 0 C, respectively, are listed in Table 10. The Co-only alloys displayed a sensitivity to overall alloying levels with this scheme which was not found in alloys containing Cr. The only Co-only alloys at 150 ksi yield strength and above were K077 and K078, while all Cr- containing alloys reached or came close to that strength level. Strength-bend properties for this process are fairly similar to those in Table 9.
• the bar was water quenched. After trimming and milling to 0.394" in order to remove the surface oxide, the alloys were co!d rolled to 0.0106" and solution heat treated in a fluidized bed furnace for the time and temperature listed in Table 11. Time and temperature were selected to achieve grain sizes below 20 ⁇ m. The alloys were then subjected to an aging anneal of 450 to 500 0 C for 3 hours, designed to increase strength and conductivity. The alloys were then cold rolled 25 % to 0.0079" and aged at 300 or 400 0 C for 3 hours. Properties measured after the second age anneal are presented in Table 12. The formabiiity was measured via V-block.
• the alloys were then cold rolled to 0.012" and solution heat treated in a fiuidized bed furnace for 60 seconds at the temperatures listed in Table 13. The temperature was selected to maintain a fairly constant grain size. The alloys were then coid rolled 25% to 0.009" and aged 450, 475 and 500 0 C for 3 hours. Properties after each aging temperature for alloys of the current example, as well as K068, K070, K072, K078, K087 and K089 are listed in Table 14. For each alloy type, yield strength decreases as the stoichiometric ratio increases above about 4.5, and falls below 120 ksi at a ratio of around 5.5.
• Table 19 were melted in a silica crucible and Durville cast into steel molds, which after gating were approximately 4" X 4" X 1.75".
• Figure 22 is a flow chart of the process of this Example 9.
• the ingots were then machined to have tapered edges, as illustrated schematically in Figure 23, to create a higher state of tensile stress at the edges. This condition is more prone to edge cracking than the standard flat edges, and thus more sensitive to alloying additions, in this case Cr.
• the alloys were soaked for two hours at 900 0 C, and rolled in two passes to 1.12" (1.4" / 1.12”) then water quenched.
• Table 21 lists the normalized casting plant yield (CPY) of six Cr-containing and four non-Cr bars, where the normalized CPY is obtained as follows: First the individualized CPY is calculated as the ratio of coil milled weight to cast bar weight. Second the bar with the highest CPY, in this case RN 03341O 1 is assigned a normalized CPY of 100%. Third the normalized CPY of all other bars is calculated by dividing the CPY of each bar by the CPY of RN033410. The normalized CPY of bars without Cr is 48-82% compares to 82-100% for the Cr-containing bars
• Figure 26A shows wear on a tool steel ball which was slid for 3000 linear inches (1500 inches on each side of the strip) under a 100 gm load over the strip surface with lard oil as a lubricant of a non-Cr sample (RN033407) that was plant solution annealed at 975°C, cold rolled 25% then aged a 450 0 C and sulfuric acid cleaned, while Figure 26B has a similar condition using a sample of a Cr-containing alloy (RN834062). The polished appearance of the ball shown in Fig.
• FIG. 26 shows that the Cr- containing alloy caused much more wear, leading to a significantly larger volume of material being removed from the ball. This is seen in Fig. 26 as a much larger wear scar for the Cr- containing alioy. The larger wear scar suggests that during stamping of a sheet of the alloy into parts, a high amount of tool wear would occur.
• Table 21a Casting plant yield of the bars, which was normalized similarly to the data of Table 21 where RN033410 is considered 100%, is given in Table 21 b.
• the CPY of the !ow-Cr bars compares favorably with the Cr-containing bars of Table 21. This is believed to be due to Cr reducing cracking during hot rolling even at these low levels.
• RN037969 has a normalized CPY% above 100 due to the fact that the yield of this bar was higher than RN033410 in the earlier example.
• the quenched bars were then soaked at 590 s C for 6 hours, trimmed and then milled to remove surface oxides developed during hot rolling.
• the alloys were then cold rolled to 0.012" and solution heat treated in a fiuidized bed furnace for 60 seconds at 950 0 C. Alloys were then subjected to an aging anneal of 475°C for 3 hours, designed to increase strength and conductivity.
• the alloys were then cold rolled 25 % to 0,009" and aged at 300 0 C for 3 hours.
• the samples were subject to cold rolling to 0.012" and solution heat treating in a fluidized bed furnace for 60 seconds at 95O 0 C, age annealing at 500 0 C for 3 hours, cold roliing 25% to 0.009", and giving a second anneal at 350 0 C for 4 hours.
• process C The alloy was rolled to 0.024" and solution heat treated in a fluidized bed furnace for 60 seconds at 95O 0 C 1 followed by cold rolling to 0.012" and a second solution heat treatment in a fluidized bed furnace for 60 seconds at 95O 0 C.
• process D cold roliing to 0.012" was followed by solution heat treatment in a fluidized bed furnace for 60 seconds at 950 0 C the alloy was cold rolled 25% to 0.009", given an aging anneal at 475 0 C for 3 hours, cold rolled 22% to 0.007", and given a final anneal of 300 0 C for 3 hours.
• process E the metal was rolled to 0.050" and given an intermediate bell anneal of 575°C for 8 hours.
• Figure 31 is a flow chart of the process of this Example 12. After cold rolling to 0.012", samples were solution annealed in a fluidized bed furnace at temperatures of 925, 950, 975 and 1000 0 C for 60 seconds. Coupons were then given age anneals at temperatures of 450, 475, 500 and 525°C for three hours. Samples were then cold rolled to final thickness at varying reductions of 15, 25 and 35%.
• Table 28 shows that the second age anneal temperature does not have a large effect on properties when the other processing variables are held constant. Conductivity was found to increase as the temperature of the second age increased, but to a small degree. Thus a wide operating range is acceptable for this step of the process.
• Table 20 were rolled in the laboratory from the coil milled condition at 0.460" down to 0.012". Subsequently samples were solution heat treated in a fluidized bed furnace for 60 seconds at 900 0 C. Coupons were then rolled 25% to 0.009" and age annealed at 425, 450 and 475°C for times of 4 and 8 hours at each temperature. Subsequently samples were cold rolled 22% to 0.007" and given a final anneal of 300 0 C for three hours. The best combination of strength and conductivity resulted from the 45O 0 C for 8 hour age, with the properties from that condition and others listed in Table 28a.
• Table 31 shows the stress relaxation data for variants BV, BW and BX. Comparing BV and BW, due to Mg addition the stress relaxation resistance increases from 66.3% to 86.6% for the 150°C/1000h condition and from 48.5% to 72.3% for the 200°C/1000h condition. The stress relaxation resistance of the higher Si-containing BX amounts to 82.3% for the 150°C/1000h condition and 68.7% for the 200°C/1000h condition.
• Figure 33 is a flow chart of the process of this Example 14. Specimens of Example 13 were subsequently cold rolled to 0.007" with a cold reduction of 22%. Thereafter the samples were aged annealed at temperatures of 300 0 C to 400 0 C for 3 hours. Properties from samples given second ages at 300 0 C are listed in Table 32. The formabitity was measured via V-block.
• Figure 35 is a flow chart of the process of this Example 16. Specimens of Example 15 were subsequently cold roiled to 0.007" with a cold reduction of 22%. Thereafter the samples were aged annealed at temperatures of 300 0 C to 35O 0 C for 3 hours. Properties from samples given second ages at 300 0 C are listed in Table 37. The formability was measured via V-block. The highest yield strength was achieved with a first aging temperature of 450 0 C. [00104] FM shows a higher yield strength of 11 ksi in comparison to FL 1 that is partly ascribed to the Mg-content and partly ascribed to the slightly higher Si-content. The yield strength, bendability and conductivity of the Cr-free FL and FM are similar to the Cr- containing BV and BW from example 15, with comparable Si-content, Ni/Co ratio and stoichiometric ratio.
• the stress relaxation resistance of the Mg-containing, Sh .39% variant FN amounts to 85.0% for the 150°C/1000h condition and 66.4% for the 200°C/1000h condition.
• Figure 36 shows the relation between 90°-minBR/t BW and yield strength for the alloys and processes of Examples 13, 14, 15, and 16. Both processes SA - CR - AA and SA - CR - AA - CR - AA form two groups with a certain formability - yield strength relation. The solid lines are just a guide to the eye and mark increasing Min BR/t and increasing yield strength with higher Si-content and/or Mg-addition. There is almost no difference in yield strength and formability - yield strength relationship between the Cr- containing and Cr-free variants.
• Figure 37 shows the relation between %IACS and yield strength for the alloys and processes of Examples 13, 14, 15, and 16.
• the Cr-free and the Cr-containing a ⁇ oys show the same capability in achieving a conductivity of 30%iACS together with high yield strength.
• the SA - CR - AA - CR - AA process achieves higher yield strength than the SA - CR - AA process, but at the same conductivity.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Conductive Materials (AREA)
• Non-Insulated Conductors (AREA)

Applications Claiming Priority (4)

Publications (3)

Family

ID=40801567

Family Applications (1)

Country Status (10)

Families Citing this family (13)

Family Cites Families (6)

• 2008
  • 2008-12-17 US US12/336,731 patent/US20090183803A1/en not_active Abandoned
  • 2008-12-19 CN CN2008801252801A patent/CN101939452A/zh active Pending
  • 2008-12-19 JP JP2010539878A patent/JP2011508081A/ja active Pending
  • 2008-12-19 KR KR1020107016153A patent/KR20100120644A/ko not_active Application Discontinuation
  • 2008-12-19 EP EP08864853.0A patent/EP3158095B1/de not_active Not-in-force
  • 2008-12-19 ES ES08864853.0T patent/ES2670425T3/es active Active
  • 2008-12-19 TW TW097149976A patent/TWI461548B/zh not_active IP Right Cessation
  • 2008-12-19 WO PCT/US2008/087705 patent/WO2009082695A1/en active Application Filing
  • 2008-12-19 MX MX2010006990A patent/MX2010006990A/es unknown
  • 2008-12-19 CA CA2710311A patent/CA2710311A1/en not_active Abandoned

Also Published As

Similar Documents

Legal Events