Microstructure And Mechanical Properties Of Al_xCrFeCuCoNi Multi-principal-Element Alloys Prepared By Powder Metallurgy

This work selecte Al,Ni,Cr,Fe,Cu and Co six elements to prepare high entropy alloys Al_xCrFeCuCoNi(x=0,0.2,0.5,0.8,1)alloys with powder metallurgy method,and study the microstructure and mechanical properties of the alloys.With the tests and analysis of the alloys,when Al=0,CrFeCuCoNi high-entropy alloy formed by FCC1 and FCC2 phase.Al_xCr FeCuCo Ni(x=0.2,0.5,0.8,1)high-entropy alloy formed by simple FCC+BCC solid solution structure,with increasing the content of Al,strongest peak strength of BCC structure changed.By the criterion of Gibbs free energy ΔG=ΔH-TΔS found that the alloy system tend to generate AlNi and compound solid solution structure,to lower the free energy of the system to stabilize.Therefore,speculate that the BCC structure of the alloy may include AlNi compounds or AlNi secondary interstitial and Fe-Cr solid solution and FCC structures are mainly Cu-rich phase solution with other elements.The mechanical properties of the alloy could be studied by the crystal structure and the property of the alloy elements.When Al=0,the hardness of Cr Fe NiCoCu alloy increased slightly with sintering temperature increasing,but the maximum hardness only has 87 HV.However the compression performance of CrFeNiCoCu alloy is preferably,which could reach at 780 MPa.The hardness and compressive properties of Al_xCrFeCuCo Ni(x=0.2,0.5,0.8,1)alloy increase along with the Al content,when the higher sintering temperature is 1300℃,the hardness of the alloy reach at 307 HV,a most excellent compressive strength shows like 1107 MPa,and 22.5% ductility are possessed by Al1.The adhesive wear is the mainly friction mechanism of Al_xCrFeCuCoNi(x=0,0.2,0.5,0.8,1)alloy,there are also exist abrasion and wear particles.The wear resistance of alloy increase along with the Al content.