On microstructure and work hardening behavior of laser powder bed fused Al-Cu-Mg-Ag-TiB2 and AlSi10Mg alloys
Abstract
In this paper, we investigate the correlation between microstructure and mechanical properties, including work hardening rates of two aluminum alloys, Al-Cu-Mg-Ag-TiB2 (A205) and AlSi10Mg, both additively manufactured using laser powder-bed fusion (LPBF) technique. Solutionizing followed by over-aging (T7) and artificial aging (T6) heat treatments were performed on as-built specimens of A205 and AlSi10Mg alloys, respectively, to investigate and compare the evolution of microstructure and tensile properties. Tensile tests based on ASTM E8/E8M standard were performed systematically on both materials in both as-built and heat-treated conditions. High-magnification microstructural characterizations including scanning electron and transmission electron microscopies and electron backscattered diffraction were performed to identify the microstructure-property correlations. The A205 alloy contains an ultrafine uniform equiaxed grain structure with no cell and/or epitaxial growth structure. However, the AlSi10Mg contains a cellular microstructure of primary α‐Al cells surrounded by a continuous cellular Si network. Tensile results on A205 (as-built) revealed discontinuous yielding, while the A205 (T7 HT) material serrated plastic flow instability. T7 heat treatment resulted in a 42.4% and 38% increase in yield stress (YS) and ultimate tensile strength (UTS), respectively, and elongation decreased from 12.5% to 9.5% consequently. However, considerable grain growth, coarsening of Si particles, and dissolution of some Mg2Si phases through solutionizing and T6 aging on AlSi10Mg resulted in increased elongation (5.49–14.20%) and decreased YS and UTS (14.5% and 19.4% respectively). The effect of distinct microstructural features of A205 and AlSi10Mg in as-built condition and their evolution in opposite directions upon aging (in terms of mechanical properties) is reflected in their work-hardening behavior. Considerably higher work hardening of AlSi10Mg alloy in both as-built and aged conditions compared to A205 is linked with the cellular structure containing hard eutectic-Si particles at the cell boundaries.
Publication Title
Materials Today Communications
Recommended Citation
Avateffazeli, M., Shakil, S., Hadadzadeh, A., Shalchi-Amirkhiz, B., Pirgazi, H., Mohammadi, M., & Haghshenas, M. (2023). On microstructure and work hardening behavior of laser powder bed fused Al-Cu-Mg-Ag-TiB2 and AlSi10Mg alloys. Materials Today Communications, 35 https://doi.org/10.1016/j.mtcomm.2023.105804
