Additively Manufactured Scalmalloy via Laser Powder Bed Fusion (L-PBF): Temperature-Dependent Tensile and Fatigue Behaviors

Abstract

This study characterized the micro-/defect-structure of laser powder bed fused (L-PBF) Scalmalloy and investigated its mechanical behavior across a wide temperature range. Hot isostatic pressing effectively reduced defect content while maintaining similar microstructure and room temperature tensile properties to stress relief condition; thus, it was applied to all specimens. Tensile and strain-controlled fatigue (fully reversed at 0.005, 0.003, 0.002, and 0.001 mm/mm amplitudes) tests were conducted from cryogenic (−195°C) to elevated temperatures (up to 400°C for tensile and 200°C for fatigue). Tensile strength decreased gradually until 100°C and then sharply at 200°C due to excessive grain boundary sliding. Fatigue resistance was consistent across temperatures at the highest strain amplitude (0.005 mm/mm) but reduced significantly at 200°C and intermediate amplitudes of 0.003 and 0.002 mm/mm. At the lowest amplitude (0.001 mm/mm), fatigue life depended more on crack-initiating defect size than temperature.