Development of cBN reinforced Ti6Al4V MMCs through laser sintering and process optimization

In this work, a systematic study and optimization on direct metal laser sintering (DMLS) of a cBN reinforced Ti6Al4V metal matrix composite (MMC) has been carried out using the response surface methodology (RSM). Variable process parameters such as volume % of cBN (5-15%), laser power (50-60W), scanning speed (3500-4500mm/min), and constant parameters such as laser spot diameter (0.2 mm), hatching gap (0.2 mm), and layer thickness (0.4) were considered for the experiments. The RSM was employed to establish a regression equation to predict different output parameters of the sintered samples such as the wear rate, relative density, and microhardness. Based on the developed model, the influence of process parameters on the wear rate, density, and microhardness were accomplished with optimized results. Hence, the result, thus, obtained showed the maximum hardness and density of 519 HV0.2 and 4.23g/cm(3), respectively, and the minimum wear of 26.49 mu m in a testing time duration of 10 minutes. X-Ray Diffraction (XRD) analysis of the fabricated MMC confirms the presence of different phases such as cBN, AlN, TiN, TiB2, and TiO2 as a consequence of a series of chemical reactions among cBN and different elements of Ti6Al4V in an argon atmosphere.