Microstructure development, mechanical properties and underlying mechanism of micro-TiN-reinforced AlSi10Mg composites fabricated by selective laser melting

In this study, aluminum matrix composites reinforced with micro-TiN were fabricated using selective laser melting (SLM) technique. The study investigates the effects of TiN content on densification, microstructure evolution, crystal textures, and mechanical properties. The results show that the relative density of composite samples containing 0?3 wt. % TiN exceeds 98%. However, further increase in TiN content leads to a decrease in relative density. The TiN particles are uniformly distributed and wetted by the AlSi10Mg matrix, forming a graded interfacial layer. The TiN particles refine the matrix grains and significantly reduce the prevalence (001) texture by promoting a heterogeneous nucleation process. In comparison to the AlSi10Mg alloy, the TiN/AlSi10Mg composite exhibits improved microhardness, tensile strength, and wear resistance. The exceptional mechanical properties of the Al matrix composites are attributed to the dispersion strengthening of the TiN particles and the fine-grain strengthening of the matrix. The optimal TiN content is found to be 3 wt. %, resulting in excellent mechanical performance of the fabricated samples (132.4?4.1 HV for hardness and 379.7?4.6 MPa for tensile strength) with a low friction coefficient of 0.49.