Mechanism and Performance Characterization of Heat Treatment on Laser-Cladded Ni-WC Coatings

To enhance the wear resistance of laser-cladded Ni-WC coatings, recrystallization and stress-relief annealing treatments were applied. The effects of different annealing treatments on the friction performance of the coatings were analyzed using XRD, SEM, and a friction wear tester. The results showed that recrystallization annealing refined the grains and transformed the Ni4B3 phase, with the lowest crack rate (10.1%) observed at 800 °C. Stress-relief annealing effectively released residual stress, achieving the lowest crack rate (6.3%) at 500 °C, while promoting the transformation of the Cr7C3 phase and improving coating stability. Furthermore, recrystallization annealing was more suitable for enhancing wear resistance, as the coating treated at 800 °C exhibited a lower friction coefficient (0.46) and the smallest wear volume (0.351 mm3). In contrast, stress-relief annealing was more effective in improving hardness, with the coating treated at 500 °C achieving the highest microhardness (936.54 HV1).