Defect evolution in PBF-LB/M-fabricated AlSi10Mg/SiC nanocomposites: quantifying porosity growth and particle agglomeration during T6 heat treatment

Purpose This study aims to investigate the effects of SiC nanoparticle reinforcement and dual T6 heat treatment on porosity evolution, microstructural integrity and mechanical performance of PBF-LB/M-fabricated AlSi10Mg nanocomposites. Particular attention is given to nanoparticle agglomeration, melt pool modification and the resulting defect–property relationships. Design/methodology/approach AlSi10Mg alloys reinforced with 1.67 Wt.% SiC nanoparticles were fabricated by PBF-LB/M and characterized in the as-built, solution heat-treated and artificially aged conditions. Phase identification was performed using X-ray diffraction, while microstructural features and defect evolution were analyzed through optical microscopy, scanning electron microscopy and quantitative image-based porosity measurements. Relative density, microhardness and tensile testing were conducted to correlate microstructural changes with mechanical performance. Findings The addition of SiC nanoparticles modified melt pool morphology and solidification behavior, increasing susceptibility to defect formation. Although the nanocomposite exhibited lower initial metallographic porosity (approximately 0.40%) than the unreinforced alloy (approximately 0.50%), solution heat treatment increased porosity to approximately 1.17% and enlarged the average pore size to approximately 327 µm². Artificial aging reduced porosity by approximately 55% and partially stabilized the defect population. The proposed image-based methodology links defect evolution to the mechanical response of PBF-LB/M-fabricated nanocomposites. Originality/value This work provides a comprehensive quantitative assessment of the interactions among nanoparticle dispersion, heat-treatment-induced defect evolution and mechanical behavior in PBF-LB/M-fabricated AlSi10Mg/SiC nanocomposites. The findings offer valuable insight into the microstructure–defect–property relationships governing additively manufactured metal matrix nanocomposites.