Liquid phase sintering of M3/2 high speed steel by selective laser sintering

SLS of M3/2 HSS results in both a liquid phase sintering and supersolidus liquid phase sintering. The formation of the agglomerates on the surface and the necklace carbide along the grain boundaries can be explained by the model of Rayleigh instability. The agglomerate size increases with increasing laser power, or decreasing scan rate. With a lower scan rate of 1 mm/s, the smooth and dense surface can be obtained. With laser power increasing from 6.25 to 25.00 W for a given scan rate of 1 mm/s, the carbide changes from the angular carbide at the three grain junction to a necklace micro structure along the grain boundaries.