CN-121992274-A - High-entropy alloy with high hardness and high corrosion resistance and single-phase BCC structure and preparation method thereof

Abstract

The invention provides a single-phase BCC structure high-entropy alloy with high hardness and high corrosion resistance and a preparation method thereof. The high-entropy alloy provided by the invention comprises the alloy components of Al, fe, ni, V and Si, wherein the molar ratio of Al, fe, ni, V to Si is 1:2:2:1:0.05. The invention is an alloy formed by Al, fe, ni, V, si elements in a specific atomic ratio (1:2:2:1:0.05), and obtains a perfect combination of single BCC phase, ultra-high hardness (more than or equal to 575 HV) and excellent corrosion resistance (less than or equal to 0.864 mu A/cm 2 ) in an as-cast state. Moreover, the preparation method of the high-entropy alloy has simple process and strong controllability, and the alloy cast ingot with uniform components and single structure can be obtained only by vacuum melting and repeated remelting without any subsequent heat treatment, so that the production flow is greatly simplified, and the energy consumption and the cost are reduced.

Inventors

• XU HANQING
• WANG ZHUOYI
• ZHANG MENGDI
• LI TIANMING
• LUO XIANGYU
• XIE YUQING

Assignees

• 河北大学

Dates

Publication Date

20260508

Application Date

20260306

Claims (10)

1. 1. A single-phase BCC structure high-entropy alloy with high hardness and high corrosion resistance is characterized by comprising the alloy components of Al, fe, ni, V and Si, wherein the molar ratio of Al, fe, ni, V to Si is 1:2:2:1:0.05.
2. 2. The high-hardness and high-corrosion-resistance single-phase BCC structure high-entropy alloy according to claim 1, characterized in that the vickers hardness of the high-entropy alloy is not lower than 575 HV and the corrosion current density is not higher than 0.864 μa/cm 2 .
3. 3. The preparation method of the single-phase BCC structure high-entropy alloy with high hardness and high corrosion resistance is characterized by comprising the following steps: (1) Calculating and weighing high-purity blocks Al, fe, ni, V and Si as metal raw materials according to an atomic ratio Al, fe, ni and V, wherein Si=1:2:2:1:0.05; (2) Placing a metal raw material into a water-cooled copper crucible of a vacuum arc melting furnace according to the sequence Si, al, V, ni, fe; (3) Vacuumizing a smelting furnace, and filling protective gas into the smelting furnace; (4) Starting an electromagnetic stirring system after all metals are completely melted to promote the convection of a melt, and then quickly solidifying the melt into ingots; (5) And (3) turning over the alloy ingot, and repeating the step (4) for a plurality of times to obtain the single-phase BCC structure high-entropy alloy with high hardness and high corrosion resistance.
4. 4. The method for producing a single-phase BCC structure high-entropy alloy with high hardness and high corrosion resistance according to claim 3, wherein the step (3) is to vacuum the melting furnace to a vacuum degree of 5.0×10 -3 Pa or less.
5. 5. The method for producing a single-phase BCC structure high-entropy alloy with high hardness and high corrosion resistance according to claim 3, wherein the step (3) is to charge argon gas as a shielding gas into the melting furnace until the pressure is slightly lower than the atmospheric pressure.
6. 6. The method for producing a single-phase BCC structural high-entropy alloy with high hardness and high corrosion resistance according to claim 3, wherein during the melting in step (4), the arcing current is first adjusted to 80-100A, and after the arc is stabilized, the melting current is raised to 300-350A.
7. 7. The method for producing a single-phase BCC structural high-entropy alloy with high hardness and high corrosion resistance according to claim 3, wherein in step (4), after all the metals are completely melted and a bright molten pool is formed, an electromagnetic stirring system is turned on, the stirring intensity is set to 70-80%, the melt is caused to flow in a countercurrent manner, and the stirring time is not less than 3 minutes.
8. 8. The method for producing a single-phase BCC structural high-entropy alloy with high hardness and high corrosion resistance as set forth in claim 3, wherein step (4) is repeated not less than 5 times in step (5).
9. 9. The method for producing a single-phase BCC structural high-entropy alloy with high hardness and high corrosion resistance according to claim 3, wherein the titanium getter is first arc-melted to absorb oxygen, nitrogen and moisture remaining in the furnace before arc-melting the metal raw material in step (4).
10. 10. The high-hardness and high-corrosion-resistance single-phase BCC structure high-entropy alloy according to claim 1 or 2 or the high-hardness and high-corrosion-resistance single-phase BCC structure high-entropy alloy prepared by the method according to any one of claims 3 to 9 for manufacturing parts subjected to high mechanical loads in corrosive environments.

Description

High-entropy alloy with high hardness and high corrosion resistance and single-phase BCC structure and preparation method thereof Technical Field The invention relates to the technical field of novel metal materials, in particular to a single-phase BCC structure high-entropy alloy with high hardness and high corrosion resistance and a preparation method thereof. Background The High-entropy alloy (High-Entropy Alloys, HEAs) is a new generation of metal materials breaking the design concept of the traditional alloy, and is generally composed of four or more main elements with equal atomic ratio or near equal atomic ratio, and further has excellent performances such as ultrahigh strength, high hardness, good wear resistance, corrosion resistance and the like beyond the traditional alloy due to the High entropy effect, lattice distortion effect, delayed diffusion effect and 'cocktail' effect. Among the numerous high-entropy alloy systems, high-entropy alloys of body-centered-cubic (BCC) structure are generally known for high strength, high hardness, mainly due to their severe lattice distortion and solid solution strengthening effects. However, such alloys often face two key technical bottlenecks, namely firstly, the poor room temperature plasticity and workability associated with BCC structures and secondly, certain alloying elements (e.g. Al, V, etc.) added to achieve high hardness may impair their corrosion resistance properties, resulting in limited application in corrosive environments. For example, in some Al-Co-Cr-Fe-Ni system alloys, the hardness increases significantly as the Al content increases to form the BCC phase, but the pitting susceptibility in chloride solutions increases. In order to balance the strength and corrosion resistance of high-entropy alloys, the prior art has adopted strategies of designing a dual-phase or multi-phase alloy, such as a eutectic high-entropy alloy, to improve plasticity through a soft ductile phase (such as an FCC phase), but the method usually has the cost of sacrificing part of strength and possibly forming a sensitive area for corrosion initiation, and performing complex thermo-mechanical treatments (such as hot rolling, annealing, aging and the like) on a single-phase alloy to optimize performance, but the complexity and manufacturing cost of the production process are obviously increased, and residual stress or tissue non-uniformity can be introduced. Therefore, the high-entropy alloy which has single and stable BCC phase in the as-cast state and can simultaneously obtain high hardness and excellent corrosion resistance without complex subsequent treatment is developed, and has great scientific significance and engineering value for simplifying the production process, reducing the cost and expanding the application of the alloy in severe environments. Disclosure of Invention The invention aims to provide a single-phase BCC structure high-entropy alloy with high hardness and high corrosion resistance and a preparation method thereof, so as to overcome the technical defects that the hardness and corrosion resistance of the existing BCC structure high-entropy alloy are difficult to be compatible, and complex subsequent heat treatment or deformation processing is often required. The invention is realized in the following way: The single-phase BCC structure high-entropy alloy with high hardness and high corrosion resistance comprises the alloy components of Al, fe, ni, V and Si, wherein the molar ratio of Al, fe, ni, V to Si is 1:2:2:1:0.05. The chemical composition of the alloy can be simply expressed as AlFe 2Ni2Vsi0.05. This component design is critical to achieving an as-cast single BCC phase and excellent balance of properties. Wherein Fe, ni, V, al mainly forms a BCC solid solution matrix, V is one of BCC structure stabilizers, which is helpful for forming a single BCC phase, and the addition of trace Si (about 0.5 at%) plays a vital role in refining the structure, further improving the strength and corrosion resistance of the alloy, and the effect is far beyond simple linear superposition. The introduction of Si not only refines grains (fine grain strengthening), but also promotes the formation of a denser and stable passivation film through grain boundary segregation, thereby improving the hardness and corrosion resistance at the same time. According to the invention, by Al, fe, ni, V, si elements, under a specific atomic ratio (1:2:2:1:0.05), the 'singular point' of the performance is realized, and the perfect combination of a single BCC phase, the ultra-high hardness (more than or equal to 575 HV) and the excellent corrosion resistance (less than or equal to 0.864 mu A/cm 2) is obtained under an as-cast state. Another object of the present invention is to provide a method for preparing the above high entropy alloy. The method has simple process and strong controllability, and the alloy cast ingot with uniform components and single structure can be obtained