Role of Si-decorated cell structure in cryogenic tensile behavior of additively manufactured AlSi10Mg alloy

Laser powder bed fusion (LPBF)-fabricated AlSi10Mg alloy exhibits markedly increased strain hardening at cryogenic temperatures because Si-assisted cell heterogeneity intensifies the accumulation of geometrically necessary dislocations and produces a strong hetero deformation induced hardening effect. However, coarse cells along melt pool boundaries promote severe strain localization that leads to early fracture without necking. This combined strengthening and weakening effect of the Si-assisted cell structure governs cryogenic tensile behavior.