Study of Process Parameter and Powder Variability on the Properties and Recrystallization Behavior of Direct Metal Laser Sintered CoCrMo

Additive manufacturing via the direct metal laser sintering (DMLS) route is an attractive technology for repair and refurbishment of gas turbine components. This paper presents the study of the role of various process parameters such as laser power, scan speed, layer thickness and powder variability in obtaining dense, pore-free parts of CoCrMo using the DMLS route. The variation in surface roughness of the built samples and the effect of powder variability on the part density were brought out via a systematic design of experiments (DOE). Different solution heat treatments were carried out to establish the recrystallization behavior of DMLS CoCrMo. The variation in microstructure and properties were evaluated between powders from two different sources, EOS and Praxair, as an important aspect towards practical applicability of the process for components.