Effect Of Al And Cu Addition On The Microstructure And Property Of High-entropy Alloys

The high entropy alloys have a lot of excellent property that the traditional alloys don’t have to be the potentially new material, such as high strength, hardness, good plasticity, good soft magnetic properties, but it is hard to achieve both strength and plasticity well. So this article changing Al and Cu atomic ratio to achieve good strength and plasticity. At present, either the experiment research or the theoretical study, the results are scarcely noticed. The formation mechanism study of the high entropy alloys is very few. From the perspective of the development of new materials, the development of high entropy alloys is of great significance.15 different contents high entropy alloys were prepared by arc melting and casting method. The mechanical property and the corrosion resistance were tested. to found the influences that the Al, Cu affecting the high entropy alloys. And to find the excellent mechanical properties high entropy alloys.In the research, according to adjust the content of Al and Cu, different content of Alx Co Cr Fe Ni Cuy high-entropy alloy were made to be studied. The effect of Al,Cu contents on the variation of phase structure, microstructure characteristic were characterized respectively by using of XRD, SEM, EDS. The hardness and the compressive property were tested. Use the electrochemical workstation and the laser microscope to research the corrosion resistance of the high entropy alloys.The results showed that the as-cast high entropy alloys is mainly composed of simple BCC and FCC solid solution. The phase structure intend to form BCC solid solution with the content of Al addition. The phase structure intend to form FCC solid solution with the content of Cu addition. Added Al elements in the alloy can improve the strength of the alloy and Cu can improve the plastic deformation ability. High entropy alloy can appear three different phases. Large amounts of Cu element is not easy to dissolve in alloy fixation at the grain boundary occur together, form the third phase. The as-cast high entropy alloys have a high hardness, high yield strength and high fracture strength, also the plastic deformation ability is very well. The as-cast Alx Co Cr Fe Ni Cuy Al4 Co Cr Fe Ni Cu2 in high entropy alloys have the greatest hardness, hardness value is 782 HV. Al3 Co Cr Fe Ni Cu has higher yield strength and fracture strength. The value of yield strength and fracture strength are 2056 MPa and 2098 MPa, The as-cast Alx Co Cr Fe Ni Cuy high entropy alloy in 3.5% Na Cl solution and in 1 mol/L HCl solution compared with stainless steel has a good corrosion resistance. High content of Al element will reduce the corrosion resistance of alloy, High content of Al element are more easy to corrosion. High concent of Cu element are also easy to corrosion. Al Co Cr Fe Ni Cu high entropy alloy has the best corrosion resistance.