Temperature-Dependent Dynamic Strain Aging in Selective Laser Melted 316L

Additively manufactured austenitic stainless steel AISI 316L (EN 1.4404, X2CrNiMo17-12-2) is used at higher temperatures, e.g., in space applications. However, the high-temperature properties of such materials have not been analyzed in detail yet. Thus, selective laser melted (SLM) 316L is tested in the solution-annealed condition by compression and tensile tests at temperatures between 25 and 877 degrees C. The compressive strength of SLM 316L is higher in comparison with the conventionally produced reference material due to hardening by a high dislocation density and a fine substructure. However, tensile tests reveal a loss in ductility of the SLM material at temperatures between 300 and 627 degrees C, where the elongation to fracture is reduced from 65% to 39%. Alloying elements cause serrated yielding in the affected temperature range. Together with an increased normalized work-hardening rate and a negative strain rate sensitivity, dynamic strain aging is found to cause the reduction of ductility.

Automated summary

The study found that 316L stainless steel manufactured using SLM technology exhibits higher compressive strength at high temperatures, but experiences a loss in ductility between 300 and 627 degrees Celsius. Alloying elements cause serrated yielding in the affected temperature range, while dynamic strain aging is identified as the cause for reduced ductility.