Manufacturing SiCp/Al composites by semi-solid metal direct writing based on mixed powder remelting

Stir casting and powder metallurgy are the mainstream technologies for manufacturing particle-reinforced aluminum matrix composites. However, particle agglomeration and extensive interfacial reaction in stir casting, as well as residual porosity in powder metallurgy, make it challenging to obtain the due performance. In this study, a semi-solid metal direct writing process based on mixed powder remelting was proposed to manufacture SiCp/Al composites. The mixed powder consisting of AlSi10Mg alloy powder, pure Al powder, and SiCp is heated to a temperature slightly exceeding the melting point of the alloy powder and then sheared to produce a paste-like semi-solid aluminum slurry with suspended SiCp. The microstructures of SiCp/Al composites were experimentally investigated and modeled, demonstrating the uniformity of SiCp and the designability of microstructural characteristics (i.e., the volume fraction and shape factor of the solid phases). The SiCp-matrix interface was also characterized to illustrate the reliable interfacial bonding due to the relatively low processing temperature. Compared with the mentioned processes, this novel approach shows superiorities in particle dispersion and interfacial reaction control. [Display omitted] •SiCp/Al composite with uniformly dispersed particles is prepared by MPR.•Pre-designing the microstructure and rheology of the composite is available.•The MPR approach enables reliable interfacial bonding between particles and matrix.•A technology for 3D printing of homogeneous and gradient composites is developed.