Differential scanning calorimetry analysis of precipitation reactions in laser additive manufactured AlSi3.5Mg2.5 alloy

Laser powder bed fusion of metals (PBF-LB/M) is a promising additive manufacturing technology for producing high-performance metallic components. Precise control of thermal process conditions is critical, particularly when working with age-hardenable alloys, as it directly impacts the microstructure, mechanical properties, and thermal characteristics of the final product. This study investigates the role of in situ temperature measurements in understanding build job-scale thermal profiles during PBF-LB/M. Experimental data from representative build jobs reveals a precipitation gradient and microstructural differences in AlSiMg alloys, as characterized by dynamic differential scanning calorimetry and metallographic analysis. These variations influence the mechanical properties and homogeneity along the build direction, as demonstrated by hardness profiling. The findings underscore that the commonly generalized as-built condition is inherently dependent on localized time-temperature profiles during the manufacturing process. Achieving an optimal balance between temperature control, cooling rates, and post-processing treatments is essential for tailoring component performance. This research provides insights into how temperature gradients during PBF-LB/M affect material behavior, contributing to enhanced process understanding and improved mechanical property optimization. • Experimental temperature measurement during the PBF-LB/M manufacturing process. • Understanding of relationships of in-situ heat treatment and precipitation state. • Investigation of the precipitation state depending on temperature using DSC.