Preparation method of instrument-grade SiCp / Al composite material with high dimensional stability

Abstract

A method for preparing an instrument-grade SiCp / Al composite material with high dimensional stability relates to a SiCp / Al composite material. To address the current issues of insufficient dimensional stability of SiCp / Al composite materials during long-term thermal cycling, as well as element enrichment at the interface between the SiCp and Al matrix and the large volume difference between the precipitated phase and the matrix, the present invention regulates the types and contents of alloying elements in the aluminum matrix to generate a fine, dispersed Al3M phase within the composite material with high thermal stability and a small volume difference with the matrix. Compared with currently commonly used instrument-grade SiCp / Al composite materials with alloying elements such as Cu, Mg, and Si, the average dimensional change rate is smaller, effectively improving the dimensional stability of the instrument-grade SiCp / Al composite material under thermal cycling.

Description

Technical Field

[0001] The invention relates to a preparation method of a SiCp / Al composite material. Background Art

[0002] Inertial instrumentation devices such as gyroscopes and accelerometers are extremely sensitive to micro-deformation of materials. Even micron-level deformation can significantly affect instrument accuracy. One of the fundamental factors that induce this micro-deformation is the instability of the material's internal microstructure. Dimensional stability refers to the ability of a material or component to maintain its original size and shape during long-term storage or service. Like hardness and strength, dimensional stability is a fundamental material property. It is independent of the material's coefficient of thermal expansion and reflects the irreversible permanent deformation that occurs over time during processing, storage, and service.

[0003] With the continuous development of the aerospace industry, the requirements for the accuracy and long-term stability of precision instruments are becoming increasingly stringent. Inertial instrument materials have undergone three generations of evolution: aluminum alloy, beryllium, and SiCp / Al composite materials. While the first-generation aluminum alloy has high thermal conductivity, its dimensional stability is poor due to factors such as a low elastic modulus and a large thermal expansion coefficient. The second-generation beryllium has a higher elastic modulus, but is toxic and expensive, limiting its widespread application. SiCp / Al composite materials offer advantages such as high specific strength and stiffness, as well as an adjustable thermal expansion coefficient. They effectively address the low-frequency noise issue associated with aluminum alloy mounting bases, while also being relatively cost-effective.

[0004] Currently, the aluminum matrix used in precision instrument-grade SiCp / Al composites is mostly composed of 2-, 5-, 6-, and 7-series aluminum. Common alloying elements include Cu, Mg, Si, Zn, and Ag. The addition of alloying elements forms a second phase, effectively hindering dislocation motion and improving the material's resistance to microplastic deformation, thereby enhancing the composite's dimensional stability. However, the diffusion coefficients of commonly used alloying elements in Al are high, and elements such as Mg and Cu often segregate. This leads to alloying elements tending to concentrate at the interface between the SiCp reinforcement and the Al matrix, resulting in an uneven overall composite composition and hindering the dimensional stability of the SiCp / Al composite during long-term thermal cycling. Furthermore, the significant difference in specific volume between the second phase and the aluminum matrix can cause changes in the sample volume during precipitation, which is also detrimental to the long-term stability of the inertial instrument material. Summary of the Invention

[0005] To address the problems of insufficient dimensional stability of current SiCp / Al composite materials during long-term thermal cycling, as well as the problems of alloy element enrichment at the interface between SiCp and the Al matrix and the large volume difference between the precipitated phase and the matrix, the present invention provides an instrument-grade SiCp / Al composite material with high dimensional stability and a preparation method thereof. By selecting alloy elements with low diffusion coefficients in Al and forming a low-density, finely dispersed second phase with a small specific volume difference with the Al matrix, the composite material helps to reduce the dimensional change of the composite material during thermal cycling and improve the dimensional stability of the composite material.

[0006] The preparation method of the instrument-grade SiCp / Al composite material with high dimensional stability of the present invention is carried out by the following steps:

[0007] 1. Weighing ingredients:

[0008] Weighing SiC powder and aluminum alloy as raw materials; the aluminum alloy provides alloying elements, the alloying elements are at least two of Sc, Er, Tm, Zr, Ti, and Nb, and the mass fraction of each alloying element in the raw materials is 0.01-0.7%;

[0009] 2. Press the SiCp preform and preheat it:

[0010] The SiC powder weighed in step 1 is placed in a mold, pre-pressed to obtain a SiCp preform, and then placed in a heating furnace for preheating;

[0011] 3. Molten Al Infiltration:

[0012] The aluminum alloy weighed in step 1 is melted to obtain a molten matrix alloy, and the molten matrix alloy is infiltrated into the preheated SiCp preform obtained in step 2 under a protective atmosphere to obtain a SiCp / Al composite material;

[0013] 4. Annealing treatment of materials:

[0014] Annealing the SiCp / Al composite material obtained in step 3;

[0015] 5. Hot and cold shock heat treatment of materials:

[0016] The SiCp / Al composite material obtained in step 4 is subjected to cold and hot shock heat treatment 4-8 times to complete;

[0017] The process of the hot and cold shock heat treatment is as follows: in a protective gas, the SiCp / Al composite material is heated to a maximum temperature and maintained for 1-3 hours, then cooled to a minimum temperature and maintained for 1-3 hours, and finally restored to room temperature; wherein the maximum temperature is 120°C, the minimum temperature is -70°C, and the heating rate and cooling rate are 5-25°C / min.

[0018] The present invention has the following beneficial effects:

[0019] 1. The SiCp / Al composite material prepared by the present invention shows excellent dimensional stability in the later cooling and heating cycles by selecting different matrix alloys and regulating the types and contents of alloying elements, with an average dimensional change rate of less than 10 -6 The dimensional change is significantly reduced, and the dimensional stability is better than that of the existing SiCp / Al composite materials with Cu, Mg, Si and other alloying elements commonly used in aluminum matrices, meeting the requirements for long-term service of precision instrument materials in high and low temperature fluctuation environments.

[0020] 2. The alloying elements added in this invention react with aluminum to form a stable cubic L12 Al3M phase. This Al3M phase serves as a heterogeneous nucleation site for aluminum, refining the grains. Furthermore, the nano-Al3M phase precipitated within the grains effectively hinders dislocation motion, increasing its resistance to dislocation movement and significantly improving the dimensional stability of the composite material.

[0021] 3. The present invention applies thermal shock treatment to SiCp / Al composites, significantly improving the composite's dimensional stability. On the one hand, due to the significant difference in thermal expansion coefficients between the SiCp reinforcement and the Al matrix, thermal mismatch stresses generated during the thermal shock process increase dislocation density, improving the composite's resistance to microdeformation. On the other hand, this increased dislocation density increases the nucleation rate of the Al3M phase in the present invention, increasing the resistance to dislocation movement and further improving the composite's resistance to microdeformation.

[0022] 4. The precipitated phase during the heat treatment process of the present invention is Al3M phase. Compared with the common Al2CuMg (S phase) and Al2Cu (θ phase), the specific volume difference between the Al3M phase and the Al matrix is ​​smaller, and the amount of element addition in the present invention is less, which can further reduce the influence of the second phase precipitation on the dimensional change of the composite material.

[0023] 5. The SiCp / Al composite material for instruments prepared by the present invention does not contain toxic elements in the matrix alloy, and is prepared by pressure infiltration. The composite material has a simple process, a wide range of applications, and is easy to realize industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a micrograph of the SiCp / Al composite material prepared in Example 1;

[0025] Figure 2 This is the cyclic size change curve of the SiCp / Al composite material prepared in Example 1. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is not limited to the specific implementation methods listed below, but also includes any reasonable combination of the specific implementation methods.

[0027] Specific embodiment 1: The preparation method of the instrument-grade SiCp / Al composite material with high dimensional stability in this embodiment is carried out according to the following steps:

[0028] 1. Weighing ingredients:

[0029] Weighing SiC powder and aluminum alloy as raw materials; the aluminum alloy provides alloying elements, the alloying elements are at least two of Sc, Er, Tm, Zr, Ti, and Nb, and the mass fraction of each alloying element in the raw materials is 0.01-0.7%;

[0030] 2. Press the SiCp preform and preheat it:

[0031] The SiC powder weighed in step 1 is placed in a mold, pre-pressed to obtain a SiCp preform, and then placed in a heating furnace for preheating;

[0032] 3. Molten Al Infiltration:

[0033] The aluminum alloy weighed in step 1 is melted to obtain a molten matrix alloy, and the molten matrix alloy is infiltrated into the preheated SiCp preform obtained in step 2 under a protective atmosphere to obtain a SiCp / Al composite material;

[0034] 4. Annealing treatment of materials:

[0035] Annealing the SiCp / Al composite material obtained in step 3;

[0036] 5. Hot and cold shock heat treatment of materials:

[0037] The SiCp / Al composite material obtained in step 4 is subjected to cold and hot shock heat treatment 4-8 times to complete;

[0038] The process of the hot and cold shock heat treatment is as follows: in a protective gas, the SiCp / Al composite material is heated to a maximum temperature and maintained for 1-3 hours, then cooled to a minimum temperature and maintained for 1-3 hours, and finally restored to room temperature; wherein the maximum temperature is 120°C, the minimum temperature is -70°C, and the heating rate and cooling rate are 5-25°C / min.

[0039] 1. In this embodiment, by selecting different matrix alloys and regulating the types and contents of alloying elements, the SiCp / Al composite material prepared in this embodiment shows excellent dimensional stability in the later cooling and heating cycles, with an average dimensional change rate of less than 10 -6The dimensional change is significantly reduced, and the dimensional stability is better than that of the existing SiCp / Al composite materials with Cu, Mg, Si and other alloying elements commonly used in aluminum matrices, meeting the requirements for long-term service of precision instrument materials in high and low temperature fluctuation environments.

[0040] 2. The alloying elements added in this embodiment react with Al to form a stable cubic L12 Al3M phase. This Al3M phase serves as a heterogeneous nucleation site for Al, refining the grains. Furthermore, the nano-Al3M phase precipitated within the grains effectively hinders dislocation motion, increasing dislocation resistance and significantly improving the dimensional stability of the composite material.

[0041] 3. This embodiment applies thermal shock treatment to SiCp / Al composites, significantly improving the composite's dimensional stability. Firstly, due to the significant difference in thermal expansion coefficients between the SiCp reinforcement and the Al matrix, thermal mismatch stresses generated during the thermal shock process increase dislocation density, improving the composite's resistance to microdeformation. Secondly, this increased dislocation density increases the nucleation rate of the Al3M phase in this embodiment, increasing the resistance to dislocation movement and further improving the composite's resistance to microdeformation.

[0042] 4. In the heat treatment process of this embodiment, the precipitated phase is Al3M phase. Compared with the common Al2CuMg (S phase) and Al2Cu (θ phase), the specific volume difference between the Al3M phase and the Al matrix is ​​smaller, and the amount of element addition in this embodiment is less, which can further reduce the influence of the second phase precipitation on the dimensional change of the composite material.

[0043] 5. The SiCp / Al composite material for instruments prepared in this embodiment does not contain toxic elements in the matrix alloy, and is prepared by pressure infiltration. The composite material has a simple process, a wide range of applications, and is easy to industrialize.

[0044] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the average particle size of the SiC powder in step 1 is 2.5-10 μm.

[0045] Specific embodiment three: This embodiment differs from specific embodiment one or two in that: the volume fraction of SiC powder in the raw material in step one is 30%-60%.

[0046] Specific embodiment 4: The difference between this embodiment and any one of specific embodiments 1 to 3 is that the aluminum alloy described in step 1 includes at least three of pure aluminum, Al-Sc alloy, Al-Er alloy, Al-Tm alloy, Al-Zr alloy, Al-Ti alloy, and Al-Nb alloy.

[0047] Specific embodiment 5: This embodiment differs from any one of specific embodiments 1 to 4 in that the pre-pressing process in step 2 is: pressurizing at a speed of 0.2-4 mm / min, pressurizing to 50-150 MPa, and maintaining the pressure for 3-10 minutes.

[0048] Specific embodiment 6: This embodiment differs from any one of specific embodiments 1 to 5 in that: the preheating process in step 2 is: the preheating temperature is 200-500° C., and the heat preservation time is 2-8 hours.

[0049] Specific embodiment seven: This embodiment differs from any one of specific embodiments one to six in that: the melting temperature of the matrix alloy in step three is 100-200° C. above the melting point of the aluminum alloy.

[0050] Specific embodiment eight: This embodiment differs from any one of specific embodiments one to seven in that: the impregnation process in step three is: the pressure is 40-180 MPa, and the impregnation speed is 2-4 mm / s.

[0051] Specific embodiment nine: This embodiment differs from any one of specific embodiments one to eight in that the annealing process in step four is: keeping warm at 200-500°C for 3-6h, then cooling to room temperature and taking out, with a cooling rate of 30-200°C / h.

[0052] Specific embodiment 10: This embodiment differs from any one of specific embodiments 1 to 9 in that: in step 5, the protective gas is nitrogen, and the protective gas pressure is 0.5-15 MPa.

[0053] Example 1

[0054] The preparation method of the instrument-grade SiCp / Al composite material with high dimensional stability in this embodiment is carried out by the following steps:

[0055] 1. Weighing ingredients:

[0056] SiC powder and aluminum alloy are weighed as raw materials; the aluminum alloy provides alloying elements, the alloying elements are Sc and Zr, and the mass fraction of Sc in the raw materials is 0.2%, and the mass fraction of Zr is 0.1%;

[0057] The average particle size of the SiC powder is 5 μm; the volume fraction of the SiC powder in the raw material is 38%;

[0058] The aluminum alloy includes pure aluminum, Al-Sc alloy and Al-Zr alloy;

[0059] 2. Press the SiCp preform and preheat it:

[0060] The SiC powder weighed in step 1 is placed in a mold, pre-pressed to obtain a SiCp preform, and then placed in a heating furnace for preheating;

[0061] The pre-pressing process is as follows: pressurizing at a speed of 2 mm / min, pressurizing to 100 MPa, and maintaining the pressure for 5 minutes;

[0062] The preheating process is as follows: preheating temperature is 300°C, and heat preservation is 3h;

[0063] 3. Molten Al Infiltration:

[0064] The aluminum alloy weighed in step 1 is melted to obtain a molten matrix alloy, and the molten matrix alloy is infiltrated into the preheated SiCp preform obtained in step 2 under a protective atmosphere to obtain a SiCp / Al composite material;

[0065] The melting temperature of the matrix alloy is 150°C above the melting point of the aluminum alloy;

[0066] The impregnation process is as follows: the pressure is 100 MPa and the impregnation speed is 3 mm / s;

[0067] 4. Annealing treatment of materials:

[0068] Annealing the SiCp / Al composite material obtained in step 3;

[0069] The annealing process is as follows: keeping the temperature at 300°C for 3 hours, then cooling to room temperature and taking out, with a cooling rate of 80°C / h;

[0070] 5. Hot and cold shock heat treatment of materials:

[0071] The SiCp / Al composite material obtained in step 4 is subjected to cold and hot shock heat treatment 6 times to complete;

[0072] The process of the hot and cold shock heat treatment is as follows: in a protective gas, the SiCp / Al composite material is heated to a maximum temperature and maintained for 2 hours, then cooled to a minimum temperature and maintained for 2 hours, and finally restored to room temperature; wherein the maximum temperature is 120°C, the minimum temperature is -70°C, the heating rate or the cooling rate is 15°C / min, the protective gas is nitrogen, and the protective gas pressure is 5 MPa.

[0073] Figure 1 This is a micrograph of the SiCp / Al composite material prepared in Example 1; it can be seen that nano-Al3M phase is precipitated inside the grains of the SiCp / Al composite material. Figure 2 The cyclic dimensional change curve of the SiCp / Al composite material prepared in Example 1. After 15 cycles at a temperature of -40°C to 80°C, a common temperature for precision instrument materials, the average dimensional change of the composite material was calculated to be 3×10 -6Compared to the commonly used SiCp / Al composite materials, the dimensional stability is one order of magnitude higher, meaning the composite material exhibits excellent dimensional stability under thermal cycling. Testing has shown that the micro-yield strength of the composite material prepared in Example 1 is 167.5 MPa.

[0074] Example 2

[0075] The preparation method of the instrument-grade SiCp / Al composite material with high dimensional stability in this embodiment is carried out by the following steps:

[0076] 1. Weighing ingredients:

[0077] SiC powder and aluminum alloy are weighed as raw materials; the aluminum alloy provides alloying elements, the alloying elements are Sc and Zr, and the mass fraction of Sc in the raw materials is 0.4% and the mass fraction of Zr is 0.2%;

[0078] The average particle size of the SiC powder is 5 μm; the volume fraction of the SiC powder in the raw material is 45%;

[0079] The aluminum alloy includes pure aluminum, Al-Sc alloy and Al-Zr alloy;

[0080] 2. Press the SiCp preform and preheat it:

[0081] The SiC powder weighed in step 1 is placed in a mold, pre-pressed to obtain a SiCp preform, and then placed in a heating furnace for preheating;

[0082] The pre-pressing process is as follows: pressurizing at a speed of 2 mm / min, pressurizing to 100 MPa, and maintaining the pressure for 5 minutes;

[0083] The preheating process is as follows: preheating temperature is 300°C, and heat preservation is 3h;

[0084] 3. Molten Al Infiltration:

[0085] The aluminum alloy weighed in step 1 is melted to obtain a molten matrix alloy, and the molten matrix alloy is infiltrated into the preheated SiCp preform obtained in step 2 under a protective atmosphere to obtain a SiCp / Al composite material;

[0086] The melting temperature of the matrix alloy is 150°C above the melting point of the aluminum alloy;

[0087] The impregnation process is as follows: the pressure is 100 MPa and the impregnation speed is 3 mm / s;

[0088] 4. Annealing treatment of materials:

[0089] Annealing the SiCp / Al composite material obtained in step 3;

[0090] The annealing process is as follows: keeping the temperature at 300°C for 3 hours, then cooling to room temperature and taking out, with a cooling rate of 80°C / h;

[0091] 5. Hot and cold shock heat treatment of materials:

[0092] The SiCp / Al composite material obtained in step 4 is subjected to cold and hot shock heat treatment 6 times to complete;

[0093] The process of the hot and cold shock heat treatment is as follows: in a protective gas, the SiCp / Al composite material is heated to a maximum temperature and maintained for 2 hours, then cooled to a minimum temperature and maintained for 2 hours, and finally restored to room temperature; wherein the maximum temperature is 120°C, the minimum temperature is -70°C, the heating rate or the cooling rate is 15°C / min, the protective gas is nitrogen, and the protective gas pressure is 5 MPa.

[0094] The average dimensional change of the SiCp / Al composite material prepared in Example 2 was 5×10 -7 Compared to the currently available SiCp / Al composite materials, the dimensional stability is two orders of magnitude higher, meaning the composite material exhibits excellent dimensional stability under thermal cycling. Testing has shown that the micro-yield strength of the composite material prepared in Example 2 is 186.2 MPa.

[0095] Example 3

[0096] The preparation method of the instrument-grade SiCp / Al composite material with high dimensional stability in this embodiment is carried out by the following steps:

[0097] 1. Weighing ingredients:

[0098] SiC powder and aluminum alloy are weighed as raw materials; the aluminum alloy provides alloying elements, the alloying elements are Sc and Zr, and the mass fraction of Sc in the raw materials is 0.6%, and the mass fraction of Zr is 0.4%;

[0099] The average particle size of the SiC powder is 5 μm; the volume fraction of the SiC powder in the raw material is 51%;

[0100] The aluminum alloy includes pure aluminum, Al-Sc alloy and Al-Zr alloy;

[0101] 2. Press the SiCp preform and preheat it:

[0102] The SiC powder weighed in step 1 is placed in a mold, pre-pressed to obtain a SiCp preform, and then placed in a heating furnace for preheating;

[0103] The pre-pressing process is as follows: pressurizing at a speed of 2 mm / min, pressurizing to 100 MPa, and maintaining the pressure for 5 minutes;

[0104] The preheating process is as follows: preheating temperature is 300°C, and heat preservation is 3h;

[0105] 3. Molten Al Infiltration:

[0106] The aluminum alloy weighed in step 1 is melted to obtain a molten matrix alloy, and the molten matrix alloy is infiltrated into the preheated SiCp preform obtained in step 2 under a protective atmosphere to obtain a SiCp / Al composite material;

[0107] The melting temperature of the matrix alloy is 150°C above the melting point of the aluminum alloy;

[0108] The impregnation process is as follows: the pressure is 100 MPa and the impregnation speed is 3 mm / s;

[0109] 4. Annealing treatment of materials:

[0110] Annealing the SiCp / Al composite material obtained in step 3;

[0111] The annealing process is as follows: keeping the temperature at 300°C for 3 hours, then cooling to room temperature and taking out, with a cooling rate of 80°C / h;

[0112] 5. Hot and cold shock heat treatment of materials:

[0113] The SiCp / Al composite material obtained in step 4 is subjected to cold and hot shock heat treatment 6 times to complete;

[0114] The process of the hot and cold shock heat treatment is as follows: in a protective gas, the SiCp / Al composite material is heated to a maximum temperature and maintained for 2 hours, then cooled to a minimum temperature and maintained for 2 hours, and finally restored to room temperature; wherein the maximum temperature is 120°C, the minimum temperature is -70°C, the heating rate or the cooling rate is 15°C / min, the protective gas is nitrogen, and the protective gas pressure is 5 MPa.

[0115] The average dimensional change of the SiCp / Al composite material prepared in Example 3 after 15 cycles at a temperature of -40°C to 80°C, a common temperature environment for precision instrument materials, is 7×10 -7 Compared to existing SiCp / Al composite materials, the dimensional stability is two orders of magnitude higher, meaning the composite material exhibits excellent dimensional stability under thermal cycling. Testing has shown that the micro-yield strength of the composite material prepared in Example 3 is 199.3 MPa.

Claims

1. A method for preparing an instrument-grade SiCp / Al composite material with high dimensional stability, characterized by: The preparation method of instrument-grade SiCp / Al composite material with high dimensional stability is carried out in the following steps:

1. Weighing ingredients: SiC powder and aluminum alloy are weighed as raw materials; the aluminum alloy provides alloying elements, the alloying elements are at least two of Sc, Er, Tm, Zr, Ti, and Nb, and the mass fraction of each alloying element in the raw materials is 0.01-0.7%; 2. Press the SiCp preform and preheat it: The SiC powder weighed in step 1 is placed in a mold, pre-pressed to obtain a SiCp preform, and then placed in a heating furnace for preheating; The pre-pressing process in step 2 is as follows: pressurizing at a speed of 0.2-4 mm / min, pressurizing to 50-150 MPa, and maintaining the pressure for 3-10 minutes; The preheating process in step 2 is as follows: preheating temperature is 200-500°C, and heat preservation is 2-8h; 3. Molten Al Infiltration: The aluminum alloy weighed in step 1 is melted to obtain a molten matrix alloy, and the molten matrix alloy is infiltrated into the preheated SiCp preform obtained in step 2 under a protective atmosphere to obtain a SiCp / Al composite material; The base alloy melting temperature in step 3 is 100-200°C above the melting point of the aluminum alloy; The impregnation process in step 3 is as follows: the pressure is 40-180 MPa and the impregnation speed is 2-4 mm / s; 4. Annealing treatment of materials: Annealing the SiCp / Al composite material obtained in step 3; The annealing process in step 4 is as follows: keeping the temperature at 200-500°C for 3-6 hours, then cooling to room temperature and taking out, with a cooling rate of 30-200°C / h; 5. Hot and cold shock heat treatment of materials: The SiCp / Al composite material obtained in step 4 is subjected to cold and hot shock heat treatment 4-8 times to complete; The process of the hot and cold shock heat treatment is as follows: in a protective gas, the SiCp / Al composite material is heated to a maximum temperature and maintained for 1-3 hours, then cooled to a minimum temperature and maintained for 1-3 hours, and finally returned to room temperature; wherein the maximum temperature is 120°C, the minimum temperature is -70°C, and the heating rate and cooling rate are 5-25°C / min; Step 5: The protective gas is nitrogen, and the protective gas pressure is 0.5-15MPa.

2. The method for preparing an instrument-grade SiCp / Al composite material with high dimensional stability according to claim 1, characterized in that: The average particle size of the SiC powder in step 1 is 2.5-10 μm.

3. The method for preparing an instrument-grade SiCp / Al composite material with high dimensional stability according to claim 1, characterized in that: The volume fraction of SiC powder in the raw material of step 1 is 30%-60%.

4. The method for preparing an instrument-grade SiCp / Al composite material with high dimensional stability according to claim 1, characterized in that: The aluminum alloy in step 1 includes at least three of pure aluminum, Al-Sc alloy, Al-Er alloy, Al-Tm alloy, Al-Zr alloy, Al-Ti alloy, and Al-Nb alloy.

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