Microstructure Evolution and Mechanical Properties of TiC Coating over Inconel 625 Obtained by Vacuum Electron Beam Surface Alloying

Inconel 625 nickel-base alloy was modified by electron beam surface alloying (EBSA) with TiC as the coating at different scanning speeds (80 mm/min, 100 mm/min, and 120 mm/min). Its microstructure evolution and friction and wear evolution were characterized using electron backscatter diffraction (EBSD), a microhardness tester, and a friction and wear tester (RTEC). The results indicated that the FCC phase in the microstructure of the Inconel 625 nickel-base alloy is island-shaped after EBSA. At different scanning speeds, the austenitic texture types will eventually form primarily S-texture accompanied by Goss texture and Brass texture of varying strengths. With an increase in scanning speed, the surface hardness of nickel-base alloys decreases. The highest surface hardness was 457 HB at 80 mm/min, and the surface hardness was 1.936 times higher than that of the base material. With an increase in scanning speed, the wear resistance of the nickel-base alloy plates decreased gradually. At the scanning speed of 80 mm/min, the wear volume and wear rate were the lowest, which were 0.9131 mm(3) and 3.0437, respectively, and the wear rate decreased by 30.48%.