Laser surface melting of 10 wt% Mo alloyed hardfacing Stellite 12 plasma transferred arc deposits: Structural evolution and high temperature wear performance

•LSM of Stellite 12 and Stellite 12 + 10 wt% Mo deposits generated duplex layer.•Duplex layer of the alloyed one was thicker.•Surface hardness of the alloyed one was higher.•Alloyed and unalloyed ones exhibited similar wear performance at RT.•Alloyed one exhibited superior performance at 500 °C due to tribo-oxidation. Laser surface melting (LSM) process has been applied on the plasma transferred arc (PTA) deposited Stellite 12 and 10 wt% Mo alloyed Stellite 12 in this study. Following the LSM process, structural and mechanical property comparison of the LSM’ed surfaces has been made. Hardness of the LSM’ed surfaces was measured as 549 HV and 623 HV for the Stellite 12 and Stellite 12 + 10 wt% Mo deposits, respectively. Despite their different hardness and structural features, the LSM’ed surfaces exhibited similar tribological performance at room temperature (RT), where fatigue wear mechanism operates. However, the wear at 500 °C promotes tribo-oxide layer formation whose composition depended on the alloying with Mo. Thus, addition of 10 wt% Mo into Stellite 12 PTA deposit has remarkably enhanced the high temperature wear performance of the LSM’ed surface as a result of participation of complex oxide (CoMoO4) in tribo-oxide layer.