Surface alloying of chromium/tungsten/stannum on pure nickel and theoretical analysis of strengthening mechanism

Abstract Surface alloying of chromium/tungsten/stannum on pure nickel were facilitated by high current pulsed electron beam (HCPEB) irradiation. The evolution of microstructure and microhardness of the irradiated surface were characterized. On the other hand, first-principles calculations, based on density functional theory (DFT), implemented in the Vienna Ab initio Simulation Package (VASP), were adopted to compute and simulate the solid solution mechanism of alloy element doping in matrix. From the simulation, the Sn atom resulted in the largest increase of lattice constant due to its largest atomic radius among three elements, and which Sn doping caused the strongest inter atomic force. Therefore, the VASP simulation indicated that Ni-Sn HCPEB irradiated sample has the highest hardness value among three different irradiated samples, which is good agreement with the experimental results obtained.