Abstract
In this study, an AlSi10Cu4Mg alloy was prepared by selective laser melting (SLM) using a mixture of pre-alloyed AlSi10Mg and elemental Cu powders, followed by aging at 180 ℃ for 2 h. The high-temperature tensile properties of both the SLMed and SLM-aged samples were tested in the temperature range of 200–400 ℃, and the microstructure changes during deformation were compared. At the temperature of 200 ℃, the SLMed sample exhibits outstanding tensile properties with an ultimate tensile strength (UTS) of 327±2 MPa and an elongation (EL) of 25.5±0.5 %. This is mainly related to the strain hardening that caused by the accumulation of anomalous dislocations near the high-volume fraction of Si nano-particles within the grains. For the SLM-aged sample, the aging treatment is found to further increase the strength, yielding a UTS of 381±3 MPa. The metastable transition of the Al2Cu phase indirectly promotes the precipitation of the nano-sized Si phase during the aging process. As the testing temperature increases, the strength increment of the SLM-aged sample gradually diminishes, while the elongation increment increases. Due to the limited intrinsic thermal stability of Si nano-particles and θ′ phase, the coarsening of the precipitates can weaken the strengthening effect. The dynamic recrystallization process can be accelerated by the aging treatment, thereby helping to improve the elongation.
Published Version
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