Investigating the Microstructural and Mechanical Characteristics of Laser Additive‐Manufactured AlSi10Mg Specimens Through Experimental and Phase‐Field Modeling Approaches

Abstract

Metal‐based additive manufacturing can make complicated parts that are complex or expensive to cast and process. Rapid cooling rates increase laser powder bed fusion (LPBF's) mechanical properties during manufacturing. The objective of this study is to examine the impact of process parameters in the L‐PBF technique on the characteristics of microstructure and mechanical properties, specifically, on the nanohardness influenced by Si segregation. The microstructures of the produced specimens are examined using field‐emission scanning electron microscopy and the analysis identifies the existence of bimodal equiaxed α‐Al grains, accompanied by Si phases located within their grain boundaries. In addition, the solidified sample exhibits the segregation of secondary precipitates, particularly Mg2Si, which results in enhanced mechanical properties. Both cellular walls and Si precipitates impede the motion and generation of dislocations, thereby influencing the overall behavior of dislocations. The examination of segregation at the top layer is conducted in a comprehensive manner, subsequently using energy‐dispersive X‐ray spectroscopy for analysis. The presence of Mg2Si, Al2MgSi2, and other phases in all samples is confirmed through X‐ray diffraction. The as‐built samples’ residual stress under different process conditions is also investigated. Additionally, the obtained microstructure is compared to a phase‐field model to forecast the evolution of the microstructure.