High-Temperature Behavior of the Heat-Treated and Overaged AlSi10Mg Alloy Produced by Laser-Based Powder Bed Fusion and Comparison with Conventional Al–Si–Mg-Casting Alloys

Abstract

In recent years, the AlSi10Mg alloy produced by laser-based powder bed fusion (L-PBF) has gained more attention for increasing the strength-to-weight ratio in structural parts subjected to severe operating conditions. Herein, the effects of thermal exposure (0–48 h at 200, 210, and 245 °C) on the metastable microstructure of the L-PBF AlSi10Mg alloy and the high-temperature (200 °C) tensile properties post-overaging (41 h at 210 °C) of the heat-treated alloy is investigated. In particular, two specific heat treatment conditions, currently neglected in the literature, are analyzed: i) T5 heat treatment (direct artificial aging: 4 h at 160 °C), and ii) the innovative T6R heat treatment (rapid solution: 10 min at 510 °C, and artificial aging: 6 h at 160 °C). The T5 shows a lower decrease in mechanical properties after thermal exposure and during the high-temperature tensile test than the T6R. This behavior is related to the higher efficiency of the submicrometric cellular structure in hindering the dislocation motion. In addition, the T5 has good tensile properties compared to high-temperature Al–Si–Mg- and Al–Si–Cu–Mg-casting alloys, representing an attractive option in future industrial applications characterized by operating temperatures up to 200 °C.