Laser melting deposition of K403 superalloy: The influence of processing parameters on the microstructure and wear performance

K403 alloy is promising in aero-engine and gas turbine components due to its outstanding mechanical properties. Here, in order to investigate the manufacturability, K403 coating was prepared on casted K403 substrate by laser melting deposition (LMD). The microstructure, microhardness, and wear performance of the coatings were studied. The results showed that the coating mainly consists of Ni3 (Al, Ti), Co3Ti and Cr3Mo. The microstructure of the coating is closely dependent on laser power. Precipitates were formed in the coating due to these high melting point elements. The highest microhardness of K403 superalloy coating is 455 HV0.2, which is 40% higher than that of casted K403 substrate. K403 superalloy coating also showed a better wear resistance than casted K403 substrate. The wear rate and friction coefficient of the K403 coating are only 41% and 70% of those of the casted K403, respectively. Furthermore, the formation of crack was discussed. We envision direct laser melting deposition of K403 superalloy can be an effective way to repair and enhance tribological performance of K403 superalloy components. •K403 superalloy coatings are successfully fabricated by laser melting deposition.•As the laser power increases, the microstructure gradually becomes coarser and the growth direction is more regular.•Flocculent precipitates Cr3Mo and granular precipitates formed by W, Mo and Ti are produced along grain boundaries.•Compared with cast K403 superalloy substrate, K403 superalloy coating has better wear resistance.