Microstructure and properties of AlCrFeNiCoCu high entropy alloy prepared by powder metallurgy

The AlCrFeNiCoCu high entropy alloy was prepared by powder metallurgy. The microstructure, hardness, corrosion resistance and compression resistance of the AlCrFeNiCoCux were measured by employing scanning electron microscopy with spectroscopy (SEM/EDS), X-ray diffraction, micro/Vickers hardness tester, electrochemical workstation and mechanical tester, respectively. The results shows that the AlCrFeNiCoCu high entropy alloy is composed of three kinds of microstructures, amplitude modulation-like, point-like and fibrous. Basic FCC and BCC crystalline structures are observed. It is found that the atoms of Al, Cr, Cu and Fe are segregated in the alloy. The alloy exhibits excellent corrosion resistance, since its self-corrosion current density is two orders of magnitude smaller than 304 stainless steel. As the radii of the atoms are different, the solid solution strengthening effect is enhanced by the large lattice distortion, which hinders the mobility of the dislocations. The alloy has a hardness of 583 HV and its compressive strength is 1341 MPa; the type of fracture is brittle cleavage. (C) 2012 Elsevier B.V. All rights reserved.