Effect of Ti content on structure and properties of Al_2CrFeNiCoCuTi_x high-entropy alloy coatings

摘要

The Al_2CrFeNiCoCuTi_x high-entropy alloy coatings were prepared by laser cladding. The structure, hard ness, corrosion resistance, wear resistance and magnetic property were studied by metallurgical micro scope, scanning electron microscopy with spectroscopy (SEM/EDS), X-ray diffraction, micro/Vickers hardness tester, electrochemical workstation tribometer and multi-physical tester. The result shows that, Al_2CrFeNiCoCuTi_x high-entropy alloy samples consist of the cladding zone, bounding zone, heat affected zone and substrate zone. The bonding between the cladding layer and the substrate of a good combina tion; the cladding zone is composed mainly of equiaxed grains and columnar crystal; the phase structure of Al_2CrFeNiCoCuTi_x high-entropy alloy coatings simple for FCC, BCC and Laves phase due to high-entropy affect. Ti element promotes the formation of a BCC structure in a certain extent. Compared with Q235 steel, the free-corrosion current density of Al_2CrFeNiCoCuTi_x high-entropy alloy coatings is reduced by 1-2 orders of magnitude, the free-corrosion potential is more "positive". With the increasing of Ti con tent, the corrosion resistance of Al2CrFeCoCuNiTi_x high-entropy alloy coatings enhanced in 0.5 mol/L HNO_3 solution. Compared with Q235 steel, the relative wear resistance of Al_2CrFeCoCuNiTi_x high-entropy alloy coatings has improved greatly; both the hardness and plasticity are affecting wear resistance. Mag netization loop shows that, Ti_(0.0) high-entropy alloy is a kind of soft magnetic materials.