The laser powder bed fusion (LPBF) technique is used to manufacture complex and customised components by exploiting the unique advantages of two types of metal materials to meet specific performance requirements. A comprehensive overview of LPBF-processed dissimilar metal materials, a combination of different single metals or alloys, is developed. The microstructure in the fusion zone and the corresponding mechanical properties of LPBF-processed dissimilar metal materials are summarised. The influence of processing factors on the mechanism of defect formation, wetting properties and element diffusion behaviour at the interface between different materials and their typical cases are scientifically investigated in detail. Particular attention is paid to energy input, Marangoni convection and interfacial bonding behaviour. The underlying science of the metallurgical structure and properties of the LPBF-processed dissimilar metal materials is revealed. The build quality and efficiency could be further improved by designing machine structures and predicting the process–property relationship. This review provides a significant guide for expanding the industrial application of LPBF-processed dissimilar metal materials.

XTiB2/Al-20%Si composite is a hypereutectic Al-20Si alloy containing x wt% TiB2 sub-micron or nanometre level in situ particles. The xTiB2/Al-20%Si composites were prepared using an 11% TiB2/Al-6Si composite as the master alloy. The phases and microstructures in the composites were evaluated by use of XRD, OM, SEM, EDS, EPMA, and TEM. The microstructural evolution of the Al-20Si alloy with the addition of TiB2 particles from 1 wt% to 6 wt% was investigated. The results showed that the primary Si, α-Al phase, and eutectic Si could be refined and modified by TiB2. Meanwhile, the crystal structures of Ti-B compound enwrapped by primary Si and α-Al phase were identified and analysed and found to form a close-packed hexagonal structure. Compared with the microstructures of composites containing different amounts of TiB2, the TiB2 particles played an important role in the nucleation of primary Si and the growth of primary Si, eutectic Si, and α-Al phases, also explaining the mechanism underpinning the effect of TiB2 on the nucleation and growth of Si and α-Al phases.