Hetero-deformation-induced stress in additively manufactured 316L stainless steel

Impact statement Heterogeneous cellular structure combined with bimodal grain structure contributed to the high hetero-deformation-induced stress in additively manufactured 316L SS, the former effect was lower compared to the latter. Heterogeneous cellular structure combined with bimodal grain structure contributed to the high hetero-deformation-induced (HDI) stress in selective laser melted 316L stainless steel (SLMed 316L SS) and high grain boundary density at molten pool boundaries and thick cellular boundaries inside grains both acted as hard domains. However, the HDI hardening rate caused by cellular boundary was lower compared with the traditional grain boundary due to its weaker dislocation motion resistance. Under high deformation, massive deformation-induced twins penetrated the cellular boundary and distorted its configuration; therefore, grain boundary heterogeneity dominated the overall HDI stress in SLMed 316L SS after large deformation.