The comparative study of thermal fatigue behavior of H13 die steel with biomimetic non smooth surface processed by laser surface melting and laser cladding
Abstract According to previous studies, the thermal fatigue behavior of hot work tool steel with biomimetic non smooth surface treated by laser surface melting (LSM) gets a significant improvement. However, the properties of LSM non smooth unit degenerate during thermal cycles. In order to improve the properties of non smooth unit during thermal cycles, laser cladding (LC) was employed to fabricate the non smooth unit. Before and after thermal fatigue testing, the microstructure and microhardness of non smooth unit treated by LSM and LC have been investigated. The results showed that the non smooth sample processed by LC is more effective to improve thermal fatigue behavior than that treated by LSM. During the thermal fatigue testing, LC non smooth unit had better resistance to thermal cycles softening compared with LSM non smooth unit. After thermal fatigue testing, a distinct change of the microstructure of LSM non smooth unit was detected, i.e. the grains of the non smooth unit became coarsening obviously. However, the microstructure of LC non smooth unit was not changed significantly after thermal fatigue testing.