Selective laser melting of stainless steel and silicon nitride fibre metal matrix composites

Abstract

Metal matrix composites are formed by adding certain filler particles to selected base metals to combine the good properties of both in the resulting composite and were proved to be quite promising in numerous applications. The main bottleneck lies in the processing methods, as the traditional solutions often lead to a loss of control on the dispersion of the filler material. The point-by-point consolidation mechanisms typical of additive manufacturing are proposed here as a possible means of enhancing this control over the composition of the metal matrix composites. Selective laser-melted composites with stainless steel 316L as the base metal and Si3 N4 as the filler phase are evaluated in the current study. The results clearly indicated that the dispersion of the filler particles is more controlled, as they are pushed and segregated around the solid front boundaries. The tensile strength of the composites is better than the pure 316L when laser-melted under appropriate process conditions. The surface quality is also substantially enhanced with the metal matrix composites.