レーザ粉末床溶融結合法によるAl-2.5%Fe-2%Mn合金造形体の機械的性質に及ぼす高温保持の影響

抄録

In this study, the effect of heat treatment at 300°C (for residual stress relief) on the mechanical properties of Al-2.5%Fe-2%Mn alloy manufactured by laser powder bed fusion (L-PBF) was investigated. Hardness measurements showed that the heat-treated sample (HT sample) exhibited comparable hardness to the as-built one (AS sample). Exposure tests at 300°C for up to 1008 hours revealed no significant change in hardness within the first 100 hours, but a decline was observed beyond this period, consistent with the AS material's behavior. Tensile tests conducted at room temperature (RT), 200°C, and 300°C demonstrated that the HT sample maintained strength and ductility comparable to literature values. Fracture surface observations revealed dimple patterns and flat regions corresponding to melt pool boundaries, indicating fracture along these boundaries. The HT sample exhibited similar fracture modes and mechanical properties to the AS sample, suggesting that the residual stress relief heat treatment does not compromise the alloy's performance. These findings indicate that the heat-treated Al-2.5%Fe-2%Mn alloy retains sufficient mechanical properties for industrial applications, making residual stress relief heat treatment a viable option for AM-fabricated components.