Effect of phase transition on the mechanical properties of FeCoCrNiMnAlx (x = 0.5, 0.75) high-entropy alloy cladding layer

The FeCoCrNiMnAlx (x = 0.5, 0.75) high-entropy alloy coatings were produced by laser cladding method, and the influence of phase transition was studied. The density and distribution of dislocation, the evolutions of phase and microstructure were investigated by using EBSD, XRD and TEM. Results presented that the higher content of Al element not only refined the grain size of the cladding layer, but also promoted the transition from FCC phase to BCC phase. All the phases in the FeCoCrNiMnAlx (x = 0.5, 0.75) cladding layers developed serious lattice distortions. The anti-plastic deformation ability of the FeCoCrNiMnAl0.75 cladding layer was effectively improved due to the accumulation of a large number of dislocations in the soft FCC phase. The yield strength and tensile strength of the FeCoCrNiMnAl0.75 cladding layers were improved significantly under the joint action of fine-grain strengthening, lattice distortion enhancement, dislocation strengthening and solid-solution strengthening.