JPH08134581A - Production of magnesium alloy - Google Patents

Abstract

PURPOSE: To produce an Mg alloy having the desired mechanical properties by adding respectively prescribed amounts or less of alloying elements, such as Li and Be, so that the S orbital energy level and the molar fraction and the mechanical properties of the alloy satisfy the prescribed calibration curves. CONSTITUTION: One or more alloying elements, selected from the group consisting of, by weight, <=25% each of Dy, Tb, and Gd, <=20% each of La, Ce, Pr, Nd, and Sm, <=10% each of Al, Ca, Cu, Zn, Y, and Ag, <=8.0% Li, <=2.O% Si, <=1.0% Zr, and <=0.1% each of Be, Na, K, Ti, V, Cr Mn, Fe, Co, Ni, Ga, Ge, Nb, Mo, Cd, In, Sn, and Sb, is added to Mg. At this time, the addition of the alloying elements is done so that the S orbital energy levels Mk, determined with respect to Mg and respective alloying elements by a molecular orbital computing method, and the molar fractions of respective alloying elements and the prescribed mechanical properties Mp of the alloy satisfy the prescribed calibration curves. By this method, the composition of the Mg alloy can easily be determined from the desired mechanical properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a magnesium alloy having predetermined mechanical properties, for example, a method for producing a magnesium alloy having a predetermined tensile strength or Vickers hardness.

[0002]

2. Description of the Related Art Magnesium alloys are used as cast products, die cast products, rolled materials, etc., and mechanical properties such as tensile strength and Vickers hardness required for magnesium alloys differ depending on their applications. Conventionally, various magnesium alloys are known, and if there is a magnesium alloy having desired mechanical properties among known magnesium alloys, there is no problem, but in the case of newly developing a magnesium alloy having desired mechanical properties, Used a so-called trial-and-error method in which the effect of each alloying element on various properties of a magnesium alloy was obtained from trial experiments and the optimum alloy composition was determined based on these data.

[0003]

However, according to the conventional trial-and-error method, the development of a magnesium alloy having desired properties requires a great deal of cost, time and labor, and is extremely inefficient. However, it is extremely difficult to carry out such a method for a multi-component magnesium alloy that has not been used in particular.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to produce a magnesium alloy whose magnesium alloy composition can be easily determined from desired mechanical properties. To provide a method.

[0005]

Means for Solving the Problems The present inventors have conducted various studies to solve the above-mentioned problems, and in order to evaluate various characteristics of the magnesium alloy, the electronic structure of the magnesium alloy is calculated by a molecular orbital calculation method ( DV-Xα cluster method). This calculation method is described in detail, for example, in "Introduction to Quantum Material Chemistry" by Hirohiko Adachi (Sankyo Publishing, 1991). By using the s-orbital energy level (hereinafter referred to as Mk) of the alloy element M in the mother metal magnesium, which is the parameter obtained from this calculation,
The inventors have found that a calibration curve of the mechanical properties of the magnesium alloy can be obtained and that the mechanical properties of the magnesium alloy can be evaluated, and have completed the present invention.

In the present invention, Mk was calculated by molecular orbital calculation using the magnesium cluster model shown in FIG. The calculated value was as shown in Table 1. Also,
In magnesium alloys, the maximum amount of each alloying element that can be added is limited by solid solubility, crystallization of brittle intermetallic compounds, availability of alloy melting, and the like. The maximum addition amount is also shown in Table 1.

[0007]

[Table 1]

Composition averaging according to alloy composition can be performed by using the above Mk value and the following formula: ΔMk = Σ | Mk _i −Mk _Mg | × X _{i In the} formula, Mk _i is the i element. Mk value, Mk _Mg is the Mk value of the Mg element, and X _i is the mole fraction of the i element. This ΔMk value correlates with mechanical properties such as tensile strength and Vickers hardness of the magnesium alloy. Therefore, a calibration curve can be obtained from the correlation between the ΔMk value and the mechanical properties of the magnesium alloy. Then, by using this calibration curve, the alloy composition having desired mechanical properties can be easily determined. On the contrary, by utilizing this calibration curve, the mechanical properties of the magnesium alloy can be determined from the alloy composition.

[0009] Specifically, the magnesium alloy, for example, the Mg-La-Ce-Nd- Sm-Gd alloy Mg-Al-Zn-Ca alloys and various compositions of various compositions △ Mk = Σ | Mk _i - Mk _Mg | × X _i was calculated. In these cases, ΔMk is represented by the formula ΔMk = | Mk _Al −Mk _Mg | × X _Al + | Mk _Zn −Mk _Mg
| × X _Zn + | Mk _Ca −Mk _Mg | × X _{Ca and the} formula ΔMk = | Mk _La −Mk _Mg | × X _La + | Mk _Ce −Mk _Mg
| × X _Ce + | Mk _Nd −Mk _Mg | × X _Nd + | Mk _Sm −Mk
_It was calculated by _Mg | × X _Sm + | Mk _Gd −Mk _Mg | × X _Gd . Correlation diagrams between the ΔMk value and the actually measured tensile strength or Vickers hardness of the magnesium alloy are as shown in FIGS. 2 and 3, respectively. This figure 2
And a calibration curve is obtained from FIG. Considering the correlation coefficient, for the tensile strength Ts (MPa) of the magnesium alloy, the equation Ts = a + bΣ | Mk _i −Mk _Mg | × X _i (where a is 135 to 147, preferably 138 to 14)
It is a value within the range of 4 and is 14 for the straight line in FIG.
1.1, b is 2432, Mk _i is M of i element
k value, Mk _Mg is the Mk value of the Mg element, and X
_i is the mole fraction of the element _i ), and the Vickers hardness Hv of the magnesium alloy is expressed by the formula Hv = a + bΣ | Mk _i −Mk _Mg | × X _i (where a is 40 to 50). , Preferably in the range of 44 to 46, 45.16 for the straight line in FIG. 3, b is 551, Mk _i is the Mk value of the i element, and Mk _Mg is the Mg element. Mk value and X _i is the mole fraction of the i element).

In the present invention, a magnesium alloy composition having desired mechanical properties can be easily determined from these calibration curves, and a magnesium alloy having desired mechanical properties can be easily produced. That is, for example, M
In the case of producing a g-Al-Ca alloy, after properly setting the Al addition amount, the Ca addition amount is set so as to satisfy the above formula for tensile strength Ts and / or the formula for Vickers hardness Hv. It can be calculated. 3 additional elements
In the case of the types, after appropriately setting the addition amounts of the two types of elements, the addition amounts of the remaining elements are set so as to satisfy the above formula for the tensile strength Ts and / or the formula for the Vickers hardness Hv. It can be calculated. It can be determined in the same manner even when the number of added elements is four or more.

Therefore, the method for producing a magnesium alloy having the desired mechanical properties according to the present invention is not more than 8.0% by weight of L.
i, 0.1% by weight or less of Be, 0.1% by weight or less of Na,
10% by weight or less of Al, 2.0% by weight or less of Si, 0.1
K less than wt%, Ca less than 10 wt%, 0.1 wt%
Ti below, V below 0.1 wt%, Cr below 0.1 wt%, Mn below 0.1 wt%, F below 0.1 wt%.
e, 0.1% by weight or less of Co, 0.1% by weight or less of Ni,
Cu less than 10% by weight, Zn less than 10% by weight, 0.1
Weight% or less Ga, 0.1 weight% or less Ge, 10 weight% or less Y, 1.0 weight% or less Zr, 0.1 weight% or less Nb, 0.1 weight% or less Mo, 10 Less than A by weight
g, 0.1% by weight or less of Cd, 0.1% by weight or less of In,
0.1 wt% or less Sn, 0.1 wt% or less Sb, 20
La by weight or less, Ce by 20% by weight or less, 20% by weight
At least one alloy selected from the group consisting of the following Pr, 20 wt% or less Nb, 20 wt% or less Sm, 25 wt% or less Gd, 25 wt% or less Tb, and 25 wt% or less Dy. Add an element so that the s-orbital energy level Mk calculated by the molecular orbital method for magnesium and each alloying element, the mole fraction of each alloying element, and the predetermined mechanical property Mp of the alloy satisfy a predetermined calibration curve. Is characterized by.

Further, the method for producing a magnesium alloy having a desired tensile strength of the present invention, specifically, comprises at least one alloy element selected from the group consisting of the above alloy elements, magnesium and each alloy element. The s-orbital energy level Mk calculated by the molecular orbital method, the mole fraction of each alloying element, and the tensile strength Ts (MPa) of the alloy are expressed by the formula Ts = a + bΣ | Mk _i −Mk _Mg | × X _i (where, a Is a value within the range of 135 to 147, b is 2432, Mk _i is the Mk value of the i element, and Mk is
_Mg is the Mk value of the Mg element, and X _i is the mole fraction of the i element).

Further, the method for producing a magnesium alloy having a desired Vickers hardness of the present invention is a molecular orbital method for magnesium and each alloying element, wherein at least one alloying element selected from the group consisting of the above alloying elements is used. The s-orbital energy level Mk, the mole fraction of each alloying element, and the Vickers hardness Hv of the alloy calculated by the equation Hv = a + bΣ | Mk _i −Mk _Mg | × X _i (where a is in the range of 40 to 50) Is the value within, and b is 55
1, Mk _i is the Mk value of the i element, and Mk _Mg is M
It is characterized in that it is added so as to satisfy the Mk value of the g element, and X _i is the mole fraction of the i element.

[0014]

【Example】

Example 1 In order to obtain an alloy in which the mechanical properties of the magnesium alloy are tensile strength of about 196 MPa (20 kgf / mm ² ) and Vickers hardness of about 58, the alloy composition is Mg-3.1 from the calibration curve of tensile strength and Vickers hardness. % Al-3.1% C
A magnesium alloy of a was prepared. The measured and calculated tensile strength and Vickers hardness for this magnesium alloy were as follows:

[0015]

In the method for producing a magnesium alloy according to the present invention, the alloy composition can be easily determined from the desired mechanical characteristics by using the calibration curve, so that the development of a new alloy can be remarkably simplified. Can quickly deal with the diversification of.

[Brief description of drawings]

FIG. 1 shows a magnesium cluster model used for calculating Mk by molecular orbital calculation in the present invention.

FIG. 2 is a tensile strength calibration curve graph showing the correlation between ΔMk value and tensile strength.

FIG. 3 is a Vickers hardness calibration curve graph showing a correlation between ΔMk value and Vickers hardness.

Claims (3)

[Claims] 1. A Li content of not more than 8.0% by weight, a Be content of not more than 0.1% by weight, a Na content of not more than 0.1% by weight, an Al content of not more than 10% by weight, an Si content of not more than 2.0% by weight, and a Si content of 0.0. K less than 1% by weight,
10% by weight or less of Ca, 0.1% by weight or less of Ti, 0.1
V less than wt%, Cr less than 0.1 wt%, 0.1 wt%
The following Mn, 0.1 wt% or less Fe, 0.1 wt% or less Co, 0.1 wt% or less Ni, 10 wt% or less C
u, 10 wt% or less Zn, 0.1 wt% or less Ga,
Ge less than 0.1 wt%, Y less than 10 wt%, Zr less than 1.0 wt%, Nb less than 0.1 wt%, 0.1 wt%
The following Mo, 10 wt% or less Ag, 0.1 wt% or less Cd, 0.1 wt% or less In, 0.1 wt% or less S
n, 0.1% by weight or less of Sb, 20% by weight or less of La,
Consists of less than 20 wt% Ce, less than 20 wt% Pr, less than 20 wt% Nb, less than 20 wt% Sm, less than 25 wt% Gd, less than 25 wt% Tb and less than 25 wt% Dy. For at least one alloy element selected from the group, the s-orbital energy level Mk calculated by the molecular orbital method for magnesium and each alloy element, the mole fraction of each alloy element, and the predetermined mechanical property Mp of the alloy are predetermined. A method for producing a magnesium alloy having desired mechanical properties, characterized by adding so as to satisfy a calibration curve. 2. A Li content of not more than 8.0% by weight, a Be content of not more than 0.1% by weight, a Na content of not more than 0.1% by weight, an Al content of not more than 10% by weight, an Si content of not more than 2.0% by weight, and a Si content of 0.0. K less than 1% by weight,
10% by weight or less of Ca, 0.1% by weight or less of Ti, 0.1
V less than wt%, Cr less than 0.1 wt%, 0.1 wt%
The following Mn, 0.1 wt% or less Fe, 0.1 wt% or less Co, 0.1 wt% or less Ni, 10 wt% or less C
u, 10 wt% or less Zn, 0.1 wt% or less Ga,
Ge less than 0.1 wt%, Y less than 10 wt%, Zr less than 1.0 wt%, Nb less than 0.1 wt%, 0.1 wt%
The following Mo, 10 wt% or less Ag, 0.1 wt% or less Cd, 0.1 wt% or less In, 0.1 wt% or less S
n, 0.1% by weight or less of Sb, 20% by weight or less of La,
Consists of less than 20 wt% Ce, less than 20 wt% Pr, less than 20 wt% Nb, less than 20 wt% Sm, less than 25 wt% Gd, less than 25 wt% Tb and less than 25 wt% Dy. For at least one alloy element selected from the group, s orbital energy level Mk calculated by the molecular orbital method for magnesium and each alloying element, the mole fraction of each alloying element, and the tensile strength Ts (MPa) of the alloy are expressed by Ts = a + bΣ | Mk _i −Mk _Zn | × X _i (where a is a value within the range of 135 to 147, b is 2432, Mk _i is the Mk value of the i element, and Mk is
_Zn is the Mk value of the Zn element, and X _i is the molar fraction of the i element). A method for producing a magnesium alloy having a desired tensile strength, characterized in that: 3. Li of less than 8.0% by weight, Be of less than 0.1% by weight, Na of less than 0.1% by weight, Al of less than 10% by weight, Si of less than 2.0% by weight, of 0.0. K less than 1% by weight,
10% by weight or less of Ca, 0.1% by weight or less of Ti, 0.1
V less than wt%, Cr less than 0.1 wt%, 0.1 wt%
The following Mn, 0.1 wt% or less Fe, 0.1 wt% or less Co, 0.1 wt% or less Ni, 10 wt% or less C
u, 10 wt% or less Zn, 0.1 wt% or less Ga,
Ge less than 0.1 wt%, Y less than 10 wt%, Zr less than 1.0 wt%, Nb less than 0.1 wt%, 0.1 wt%
The following Mo, 10 wt% or less Ag, 0.1 wt% or less Cd, 0.1 wt% or less In, 0.1 wt% or less S
n, 0.1% by weight or less of Sb, 20% by weight or less of La,
Consists of less than 20 wt% Ce, less than 20 wt% Pr, less than 20 wt% Nb, less than 20 wt% Sm, less than 25 wt% Gd, less than 25 wt% Tb and less than 25 wt% Dy. For at least one alloying element selected from the group, the s-orbital energy level Mk calculated by the molecular orbital method for magnesium and each alloying element, the mole fraction of each alloying element, and the Vickers hardness Hv of the alloy are expressed by the formula Hv = a + bΣ | Mk _i −Mk _Mg | × X _i (where a is a value in the range of 40 to 50, and b is 55).
1, Mk _i is the Mk value of the i element, and Mk _Mg is Z
A magnesium alloy having a desired Vickers hardness, characterized in that it is added so as to satisfy the Mk value of the n element and X _i is the mole fraction of the i element.