Effects of Micron/Submicron TiC on Additively Manufactured AlSi10Mg: A Comprehensive Study from Computer Simulation to Mechanical and Microstructural Analysis

The Al-based metal matrix composites (AMMCs) reinforced by micron- and submicron-scale TiC ceramic particles were manufactured by selective laser melting (SLM) additive manufacturing. The influences of SLM processing parameters such as volumetric energy density (ɛ) and laser absorptivity of powders on the densification, microstructural evolution, mechanical behavior and corrosion behavior of the AMMCs were systematically studied, based on which the strengthening mechanisms of the SLM-processed AMMC components were clarified. Finite element simulation was run to assist in revealing the underlying mechanism. Fundamental processes such as the Marangoni flow were discussed. Through these efforts, the as-printed AlSi10Mg/1 μm TiC was SLMed into crack-free, high-density parts (= 99.2%) when ɛ was > 65 J/mm3. For the as-printed AlSi10Mg/1 μm TiC samples prepared by the best SLM parameters, high tensile strength (470 ± 14 MPa) was achieved. Average hardness of ~ 169 HV0.1 and a considerably low friction coefficient with a mean value of ~ 0.3 were also obtained. The homogeneously distributed submicron TiC particles reduced the wear rate to 1.68 × 10−11 mm3/N/m. The as-printed AlSi10Mg/1 μm TiC parts showed better performance on corrosion resistance as well due to the high relative density achieved along with continuous and compatible bonding interfaces with the Al alloy matrix. Use of large-sized TiC (e.g., 30 μm) particles should be avoided, however, since they led to reduced mechanical properties and a poorer corrosion resistance.