A method for regulating the strength or plasticity of a ti zr hf nb high-entropy alloy

Abstract

The present application relates to TiZrHfNb high-entropy alloy technical field, especially point to a kind of method for regulating and controlling TiZrHfNb high-entropy alloy strength or plasticity, TiZrHfNb high-entropy alloy in each element of Ti, Zr, Hf, Nb is expressed as a, b, c, d in order in atomic percentage Content, wherein, control c=d and d is in 5at. 35at.%, a+b=M, and a and b are regulated and controlled as follows: when the target is to improve the strength of TiZrHfNb high-entropy alloy, a and b are controlled to be close to M / 2, and the absolute value of the difference between a and b and M / 2 is 0at. 2at.%; when the target is to improve the plasticity of TiZrHfNb high-entropy alloy, a and b are controlled to deviate from M / 2, and the absolute value of the difference between a and b and M / 2 is ≥10at.%. The present application can accurately regulate and control according to the required strength or plasticity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of TiZrHfNb high-entropy alloy, in particular to a method for regulating the strength or plasticity of TiZrHfNb high-entropy alloy. BACKGROUND

[0002] High-entropy alloy is a multi-principal element, equal atomic ratio or near equal atomic ratio alloy, which has the characteristics of multi-principal element composition, high thermodynamic entropy, lattice distortion and slow diffusion. Its high strength, high hardness, good toughness, fatigue resistance, corrosion resistance and radiation resistance and other mechanical and service properties make high-entropy alloy have potential applications in many fields. High-entropy alloy exhibits more excellent yield strength-fracture toughness matching than nickel-based high-temperature alloy and titanium alloy, and has become a candidate material for a new generation of high-strength and tough structural components, and has attracted widespread attention from researchers.

[0003] However, the composition space of TiZrHfNb high-entropy alloy is very extensive. However, improper composition adjustment can easily cause the mechanical properties of the alloy to deviate from the expected value. However, there is no report on how to accurately regulate the strength or plasticity of TiZrHfNb high-entropy alloy in the prior art. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a method for regulating the strength or plasticity of TiZrHfNb high-entropy alloy, which fills the gap in the method for regulating the strength or plasticity of TiZrHfNb high-entropy alloy, and can accurately regulate the strength or plasticity according to the required regulation.

[0005] To solve the above technical problems, the present application provides the following technical scheme:

[0006] A method for regulating the strength or plasticity of TiZrHfNb high-entropy alloy, the content of each element of Ti, Zr, Hf and Nb in the TiZrHfNb high-entropy alloy is represented as a, b, c and d in atomic percentage, respectively, wherein c=d and d is in the range of 5at.% to 35at.%, a is in the range of 15at.% to 50at.%, preferably 15at.% to 45at.%, b is in the range of 15at.% to 50at.%, preferably 15at.% to 45at.%, a+b=M, and a and b are regulated as follows:

[0007] When the target is to improve the strength of TiZrHfNb high-entropy alloy, a and b are both controlled to be close to M / 2, and the absolute value of the difference between a and b and M / 2 is in the range of 0at.% to 2at.%;

[0008] When the target is to reduce the strength of TiZrHfNb high-entropy alloy, a and b are both controlled to deviate from M / 2, and the absolute value of the difference between a and b and M / 2 is greater than or equal to 10at.%;

[0009] In the case of improving the plasticity of the TiZrHfNb high-entropy alloy, a and b are controlled to deviate from M / 2, and the absolute value of the difference between a and M / 2 and the absolute value of the difference between b and M / 2 are both greater than or equal to 10 at.%.

[0010] In the case of reducing the plasticity of the TiZrHfNb high-entropy alloy, a and b are controlled to be close to M / 2, and the absolute value of the difference between a and M / 2 and the absolute value of the difference between b and M / 2 are both within 0 at.%-2 at.%.

[0011] Preferably, the method for regulating the strength or plasticity of the TiZrHfNb high-entropy alloy further comprises determining the values of c and d first, and then regulating a and b according to the target.

[0012] Preferably, the method for regulating the strength or plasticity of the TiZrHfNb high-entropy alloy further comprises, after determining the content of each component, melting the raw materials to prepare, and then annealing. The annealing conditions may, for example, include annealing at 1100-1300°C for 20-30h.

[0013] Preferably, in the case of improving the strength of the TiZrHfNb high-entropy alloy, |a-b| is also controlled to be within 0 at.%-2 at.%, which is more conducive to exerting the solid solution strengthening of the high-entropy alloy, so that the TiZrHfNb high-entropy alloy is near the peak value of strength.

[0014] Preferably, in the case of reducing the strength of the TiZrHfNb high-entropy alloy, |a-b| is also controlled to be within 10 at.%-40 at.%, which is more conducive to deviating from the solid solution strengthening of the TiZrHfNb high-entropy alloy, so as to weaken the strengthening effect of the TiZrHfNb high-entropy alloy.

[0015] Preferably, in the case of improving the plasticity of the TiZrHfNb high-entropy alloy, a-b is also controlled to be within 10 at.%-40 at.%, and more preferably 10 at.%-30 at.%, which is more conducive to making the TiZrHfNb high-entropy alloy deviate from the high solid solution strengthening region, and utilizing the alloy strength-plasticity mutual exclusion effect to produce better alloy plasticity.

[0016] Preferably, in the case of reducing the plasticity of the TiZrHfNb high-entropy alloy, |a-b| is also controlled to be within 0 at.%-2 at.%, which is more conducive to making the TiZrHfNb high-entropy alloy be in the high solid solution strengthening region, and utilizing the alloy strength-plasticity mutual exclusion effect to produce poor TiZrHfNb high-entropy alloy plasticity.

[0017] Preferably, c=d and d is within 20 at.%-30 at.%, which is more conducive to guaranteeing the basic strength and plasticity of the TiZrHfNb high-entropy alloy.

[0018] Preferably, b is between 14 at.% and 34 at.%.

[0019] The TiZrHfNb high-entropy alloy of the present invention can be, for example, Ti. 34 Zr 14 Hf 26 Nb 26 Ti 30 Zr 18 Hf 26 Nb 26 Ti 26 Zr 22 Hf 26 Nb 26 Ti 22 Zr 26 Hf 26 Nb 26 Ti 18 Zr 30 Hf 26 Nb 26 Ti 14 Zr 34 Hf 26 Nb 26 These can be represented as 14Zr, 18Zr, 22Zr, 26Zr, 30Zr, and 34Zr, respectively. The X-ray diffraction patterns of the alloys corresponding to 14Zr, 18Zr, 22Zr, 26Zr, 30Zr, and 34Zr are shown below. Figure 1 As shown, the alloy exhibits a single-phase BCC solid solution structure. The true stress-true strain curves for the alloys corresponding to 14Zr, 18Zr, 22Zr, 26Zr, 30Zr, and 34Zr are shown below. Figure 2 As shown, when the atomic percentages of Hf and Nb are both 26 at.%, the tensile strength first increases and then decreases with increasing Zr content, while the elongation at break shows the opposite trend, first decreasing and then increasing. The strength and plasticity of the TiZrHfNb high-entropy alloy exhibit significant compositional asymmetry; the 14Zr alloy has better plasticity than the 34Zr alloy. When the Ti and Zr contents are close, the 26Zr alloy has higher strength, but its plasticity is the lowest. Figure 3 As shown, this is because the strength and plasticity of the TiZrHfNb high-entropy alloy are mutually exclusive; as the strength increases, the plasticity of the alloy decreases.

[0020] The TiZrHfNb high-entropy alloy of this invention is an alloy composed of elements such as titanium (Ti), zirconium (Zr), hafnium (Hf), and niobium (Nb). Besides titanium (Ti), zirconium (Zr), hafnium (Hf), and niobium (Nb), it may also contain elements such as vanadium (V), molybdenum (Mo), and tantalum (Ta). The TiZrHfNb high-entropy alloy is a body-centered cubic single-phase alloy.

[0021] In a specific embodiment, c = d = 26 at.%, and when the target is to improve the plasticity of the TiZrHfNb high-entropy alloy, a = 34 at.%, b = 14 at.% are controlled, which can exhibit better plasticity; and when the target is to improve the strength of the TiZrHfNb high-entropy alloy, a = b = 24 at.% are controlled, which can exhibit better strength.

[0022] Preferably, the tensile strength of the TiZrHfNb high-entropy alloy is between 600 MPa and 700 MPa.

[0023] Preferably, the elongation at break of the TiZrHfNb high-entropy alloy is between 2% and 18%.

[0024] It is found through research that, since the composition space of the TiZrHfNb high-entropy alloy is very extensive, if the composition is not properly adjusted, the mechanical properties can easily deviate from the expectation. The present application studies the influence of different Zr contents on the tensile strength and elongation at break of the TiZrHfNb high-entropy alloy, and uses the tensile strength to measure the strength of the high-entropy alloy and uses the elongation at break to measure the plasticity of the high-entropy alloy. It is further found that, when the atomic percentages of Hf and Nb are the same, with the increase of the Zr content, the tensile strength shows a trend of first increasing and then decreasing, while the elongation at break shows an opposite trend, i.e., first decreasing and then increasing. In addition, the strength and plasticity of the TiZrHfNb high-entropy alloy show obvious composition asymmetry, and the plasticity of the alloy rich in Ti is better than that of the alloy rich in Zr. When the Ti content and the Zr content are close, the alloy has high strength, but the plasticity is the lowest at this time. It is further found that the strength or plasticity of the TiZrHfNb high-entropy alloy can be adjusted by adjusting the content of the Zr element according to a specific method. Based on this, the present application is further proposed.

[0025] The beneficial effects of the above technical solutions of the present application are as follows:

[0026] 1) According to the present application, the tensile strength of the TiZrHfNb high-entropy alloy can be precisely adjusted, and the elongation at break of the TiZrHfNb high-entropy alloy can be precisely adjusted, by a specific method, especially by controlling c = d and being in a suitable range, and by regulating the Ti and Zr contents according to a specific method.

[0027] 2) According to the present application, blind trial and error of alloy composition can be avoided, and a TiZrHfNb high-entropy alloy with reasonable high strength or plasticity can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The above are X-ray diffraction patterns of several TiZrHfNb high-entropy alloys of the present application, and the Hf and Nb contents of the alloys are both 26 at.%.

[0029] Figure 2 True stress-true strain curves of several TiZrHfNb high-entropy alloys of the present application, with Hf and Nb contents of 26 at. %.

[0030] Figure 3 Tensile strength and elongation at break of the TiZrHfNb high-entropy alloy 26Zr of the present application, with Hf and Nb contents of 26 at. %, the 26Zr alloy being Ti 22 Zr 26 Hf 26 Nb 26 .

[0031] Figure 4 True stress-true strain curves of a TiZrHfNb high-entropy alloy of one embodiment of the present application, with Hf and Nb contents of 20 at. %.

[0032] Figure 5 True stress-true strain curves of a TiZrHfNb high-entropy alloy of one embodiment of the present application, with Hf and Nb contents of 30 at. %. DETAILED DESCRIPTION

[0033] To make the technical problems, technical solutions and advantages of the present application clearer, specific embodiments will be described in detail below with reference to the accompanying drawings.

[0034] Embodiment 1

[0035] A TiZrHfNb high-entropy alloy was obtained by melting each raw material and then annealing at 1200°C for 24h, with Hf and Nb contents of 20 at. % in the alloy. The composition of the high-entropy alloy is shown in Table 1.

[0036] Table 1: Chemical composition of TiZrHfNb high-entropy alloy, in at. %

[0037] Alloy No. Ti Zr Hf Nb 10Zr 50 10 20 20 30Zr 30 30 20 20

[0038] The total content of Ti and Zr is 60 at. %. In order to make the TiZrHfNb high-entropy alloy have higher strength, the atomic percentage of Ti and Zr can be made close to each other, i.e. Ti = Zr = 30 at. %.

[0039] The total content of Ti and Zr is 60 at. %. In order to make the TiZrHfNb high-entropy alloy have higher plasticity, the atomic percentage of Ti and Zr can be made deviate from 30 at. %, and the content of Ti is higher than that of Zr. Ti = 50 at. % and Zr = 10 at. % can be selected.

[0040] The true stress-true strain curves of each alloy are shown in Figure 4As shown in FIG. 2, the 10Zr alloy exhibits high plasticity, with a fracture elongation of 10.7%; and the 30Zr alloy exhibits high strength, specifically 672.3 MPa.

[0041] Example 2

[0042] The TiZrHfNb high-entropy alloy is obtained after melting of each raw material and then annealing at 1200°C for 24 hours, and the Hf and Nb contents of the alloy are both 30 at.%. The composition of the high-entropy alloy is shown in Table 2.

[0043] Table 2: Chemical composition of the TiZrHfNb high-entropy alloy, in at.%

[0044] Alloy No. Ti Zr Hf Nb 10Zr 30 10 30 30 20Zr 20 20 30 30

[0045] The total content of Ti and Zr is 40 at.%. In order to target the TiZrHfNb high-entropy alloy to have high strength, the atomic percentage of Ti and Zr is close to Ti=Zr=20 at.%.

[0046] The total content of Ti and Zr is 40 at.%. In order to target the TiZrHfNb high-entropy alloy to have high plasticity, the atomic percentage of Ti and Zr deviates from 20 at.%, and the content of Ti is higher than that of Zr. Ti=30 at.% and Zr=10 at.% can be selected.

[0047] The true stress-true strain curves of each alloy are shown in FIG. 4. Figure 5 As shown in FIG. 4, the 10Zr alloy exhibits high plasticity, with a fracture elongation of 17.8%; and the 20Zr alloy exhibits high strength, specifically 680.2 MPa.

[0048] The strength and plasticity exhibited by the embodiments of the present application are obtained by the method proposed in the present application, and the adjustment of the performance of the TiZrHfNb high-entropy alloy is achieved by regulating the Ti and Zr elements by a special method.

[0049] Example 3

[0050] The method of Example 1 is referred to, except that the absolute value of the difference between the contents a and b of Ti and Zr and M / 2 is 2 at.%, a=32 at.% and b=28 at.%. The TiZrHfNb high-entropy alloy is denoted as 28Zr.

[0051] In the TiZrHfNb high-entropy alloy of this example, the absolute value of the difference between the contents a and b of Ti and Zr and M / 2 of the 28Zr alloy is 2 at.%, which exceeds the absolute value of the difference between a and b of the 30Zr alloy and M / 2 in Example 1, which is 0 at.%, so the alloy exhibits slightly lower strength, specifically 669.8 MPa.

[0052] Comparative Example 1

[0053] The method of Example 1 was followed, except that the absolute value of the difference between a and b from M / 2 was 3 at.%, a = 33 at.%, b = 27 at.%. The TiZrHfNb high-entropy alloy is denoted as 27Zr.

[0054] The 27Zr alloy exhibited a lower strength relative to the 28Zr alloy, specifically 665.2 MPa, in the TiZrHfNb high-entropy alloy of this comparative example.

[0055] Comparative Example 2

[0056] The method of Example 1 was followed, except that the absolute value of the difference between a and b from M / 2 was 5 at.%, a = 25 at.%, b = 15 at.%. The TiZrHfNb high-entropy alloy is denoted as 15Zr.

[0057] The 15Zr alloy exhibited a worse plasticity relative to the 10Zr alloy of Example 2, specifically 16.9%, in the TiZrHfNb high-entropy alloy of this comparative example, due to the absolute value of the difference between a and b from M / 2 being 5 at.%, which is lower than the 10% difference of the 10Zr alloy of Example 2.

[0058] The above describes the preferred embodiments of the present application. It should be noted that, for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered as falling within the scope of protection of the present application.

Claims

1. A method of modulating the strength or ductility of a TiZrHfNb high-entropy alloy, characterized in that, The TiZrHfNb high-entropy alloy is a body-centered cubic single-phase alloy; the content of each element of Ti, Zr, Hf and Nb in the TiZrHfNb high-entropy alloy is represented as a, b, c and d in atomic percentage in turn, wherein c=d and d is 5 at.%-35 at.%, a is 15 at.%-50 at.%, b is 15 at.%-50 at.%, a+b=M, and a and b are regulated as follows: When the target is to improve the strength of the TiZrHfNb high-entropy alloy and reduce the plasticity of the TiZrHfNb high-entropy alloy, a and b are both controlled to be close to M / 2, and the absolute value of the difference between a and b and M / 2 is 0 at.%-2 at.% respectively; When the target is to reduce the strength of the TiZrHfNb high-entropy alloy and improve the plasticity of the TiZrHfNb high-entropy alloy, a and b are both controlled to deviate from M / 2, and the absolute value of the difference between a and b and M / 2 is ≥10 at.% respectively.

2. The method for controlling the strength or plasticity of TiZrHfNb high-entropy alloys according to claim 1, characterized in that, When the target is to improve the strength of the TiZrHfNb high-entropy alloy and reduce the plasticity of the TiZrHfNb high-entropy alloy, |a-b| is also controlled to be 0 at.%-2 at.%.

3. The method for controlling the strength or plasticity of TiZrHfNb high-entropy alloys according to claim 1, characterized in that, When the target is to reduce the strength of the TiZrHfNb high-entropy alloy and improve the plasticity of the TiZrHfNb high-entropy alloy, |a-b| is also controlled to be 20 at.%-35 at.%.

4. The method for regulating strength or plasticity of a TiZrHfNb high-entropy alloy according to any one of claims 1-3, characterized in that, The method for regulating the strength or plasticity of the TiZrHfNb high-entropy alloy further comprises: first determining the values of c and d, and then regulating a and b according to the target.

5. The method for controlling the strength or plasticity of TiZrHfNb high-entropy alloys according to claim 1, characterized in that, c=d and d is 20 at.%-30 at.%.

6. The method for controlling the strength or plasticity of TiZrHfNb high-entropy alloys according to claim 1, characterized in that, The method for regulating the strength or plasticity of the TiZrHfNb high-entropy alloy further comprises: after determining the content of each component, melting the raw materials to prepare, and then annealing.

7. The method for controlling the strength or plasticity of TiZrHfNb high-entropy alloys according to claim 1, characterized in that, The tensile strength of the TiZrHfNb high-entropy alloy is 600 MPa-700 MPa, and / or the elongation at break of the TiZrHfNb high-entropy alloy is 2%-18%.

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