In this work, the structural and mechanical characteristics of Cu₅₀Zr₄₃Al₇ bulk metallic glass (BMG) fabricated by selective laser melting (SLM) are studied and the impacts from the SLM process are clarified. Cu₅₀Zr₄₃Al₇ alloy specimens were manufactured by the SLM method from corresponding gas-atomized amorphous powders. The as-built specimens were examined in terms of phase structure, morphologies, thermal properties and mechanical behavior. The x-ray diffraction and differential scanning calorimetry results showed that structural relaxation and partial crystallization co-exist in the as-fabricated Cu₅₀Zr₄₃Al₇ glassy samples. The nano- and micro- hardness and the elastic modulus of the SLM-fabricated Cu₅₀Zr₄₃Al₇ BMG were higher than CuZrAl ternary BMGs with similar compositions prepared by conventional mold casting, which can be attributed to the structural relaxation in the former sample. However, the macro compressive strength of the SLM-fabricated Cu₅₀Zr₄₃Al₇ BMG was only 1044 MPa mainly due to its porosity. This work suggests that the SLM process induced changes in structural and mechanical properties are significant and cannot be neglected in the fabrication of BMGs.

Multisized nanoparticles (MPs) are widely employed as electronic materials to form conductive patterns, benefitting from their excellent sintering properties and mechanical reliability. However, due to the lack of effective detection methods for the real-time sintering process, it is difficult to reveal the sintering behavior during the MPs sintering process. In this work, a molecular dynamics method is used to track the trajectory of silver atoms. The melting behavior of a single nanoparticle (SP) is first discussed. The structural evolution of equally sized nanoparticles (EPs) and unequally sized nanoparticles (UPs) during the sintering process is analyzed alongside morphology changes. It is proposed that the UPs sintering process benefits from the wetting behavior of small-sized nanoparticles on the surface of large-sized nanoparticles, and the sintering angle (θ) is proposed as an index to estimate the sintering result of UPs. Based on the works above, three basic sintering modes and one advanced sintering mode in the MP sintering process are analyzed emphatically in this paper, and the roles of different-sized nanoparticles in MPs are concluded from simulation and experimental results. This work provides theoretical support for conductive ink composition design and sintering process optimization.