Effect of Cr content on microstructures and properties of CoNiCuCrx medium entropy alloys

Abstract

CoNiCuCr x (x=0,0.4,1) medium entropy alloys (MEAs) were prepared by powder metallurgy technology, and the effects of Cr content on the microstructures and properties of the alloys were studied. The results show that the CoNiCu MEA consists of FCC1 solid solution phase and FCC2 solid solution phase. With Cr addtion, some new phases appear in the CoNiCuCr x MEAs, and they are FCC3 solid solution phase, BCC solid solution phase and a small number of NiCoCr intermetallic compound. The new structural phase improves the hardness, compressive yield strength, compressive strength and wear resistance of the MEAs, with the increase of Cr content. NiCoCuCr MEA shows good comprehensive mechanical properties, and the hardness, compressive yield strength, compressive strength and specific wear rate are 331 MPa, 511.87 MPa, 1142.71 MPa and 4.09×10-4 mm3/N⋅m respectively.