Microstructure and mechanical behavior of TiCN reinforced AlSi10Mg composite fabricated by selective laser melting

Although Al alloys have been extensively used for additive manufacture, TiCN reinforced Al composites have rarely been investigated for the feasibility of additive manufacture. In this study, TiCN reinforced AlSi10Mg composite was fabricated by selective laser melting (SLM). The key SLM process parameters, including laser power, scanning speed, as well as hatch spacing were optimized through design of experiment (DOE) and the effects of these parameters on relative density of SLMed AlSi10Mg -5 vol% TiCN composite were investigated. In addition, the effect of T6 heat treatment after SLM processing on microstructure and mechanical properties of AlSi10Mg -5 vol% TiCN composite was also studied. Research results show that the optimal SLM parameters are laser power of 370 W, scanning speed of 1760 mm/s, and hatch spacing of 0.063 mm, corresponding to the maximum relative density of 98.5% for SLMed AlSi10Mg -5 vol% TiCN. Noticeable diffusion of Al and Si ele-ments from matrix to TiCN particles occurs while there is no observed new phase formation between TiCN and Al matrix during SLM process, which enhanced the bonding strength between the TiCN and AlSi10Mg matrix. As compared with the SLMed pure AlSi10Mg, AlSi10Mg-TiCN shows apparently higher hardness, ultimate tensile strength and compression strength due to the significant refinement of AlSi10Mg matrix and the strengthening effect from TiCN particles.