Modulating fracture toughness through processing-mediated mesostructure in additively manufactured Al-12Si alloy

Al-12Si alloy processed through additive manufacturing exhibits a complex hierarchical structure. At the mesoscale, its melt pool boundaries constitute network of weak interfaces that provides preferred pathways for crack kinking, leading to both marked anisotropy and apparent enhancement in fracture energy. In this study, multiscale cohesive zone-based computational model semi-analytical approach kinked cracks are used investigate effect configuration on energy due path tortuosity. We experimentally validate our methodology using toughness testing compact tension specimens, then systematically study simultaneous effects hatch spacing, layer thickness, surface orientation variations While increases with increasing spacing decreasing processing defects such as keyholing give practical limits geometry, limiting enhancement. found can be enhanced high factor two an optimal is linearly proportional ratio thickness varies between 60° 100°.