Experimental testing demonstrates that interpass temperature controls dynamic yield strength in printed 316L steel, indicating thermal control optimizes high-strain-rate performance.
Key Points
To assess how interpass temperature affects the dynamic tensile deformation behavior, strain-rate sensitivity, and microstructural evolution of wire arc additively manufactured 316L stainless steel.
Fabricated 316L stainless steel specimens via cold metal transfer-based wire arc additive manufacturing at interpass temperatures of room temperature, 200 °C, and 400 °C.
Conducted dynamic tensile testing across nominal strain rates of 100 s−1, 500 s−1, and 1000 s−1 using digital image correlation for strain mapping and scanning electron microscopy for fractographic evaluation.
Increasing interpass temperature promoted microstructural coarsening, decreased average hardness from 182 HV1 at room temperature to 173 HV1 at 200 °C and 161 HV1 at 400 °C, and disrupted the continuity of the retained δ-ferrite network.
Room-temperature specimens exhibited the highest 0.2% proof stress at 100 s−1 and 500 s−1, while proof stress responses converged among all temperature conditions at 1000 s−1.
Specimens across all conditions failed via ductile dimple rupture and microvoid coalescence, with digital image correlation revealing more homogeneous centerline strain distribution at the highest strain rate.