High temperature mechanical properties of wire-arc directed energy deposited Al-Ce-Mg alloy

The Al-15Ce-3Mg (wt%) alloy was fabricated by wire-arc based directed energy deposition (WA-DED), and its high temperature mechanical properties were investigated to facilitate the development of Al-Ce-Mg alloys. The WA-DED Al-15Ce-3Mg alloy forms hypereutectic microstructure, which mainly includes large primary Al₁₁Ce₃ intermetallics and fine Al₁₁Ce₃/α-Al eutectics. The WA-DED Al-15Ce-3Mg alloy has high strength and good plastic deformation ability at high temperatures, under the combined effects of precipitation strengthening and solid solution strengthening. Its tensile strength can reach 86–132 MPa at 220–300 °C, which is similar to that of LPBF-formed and HIP-treated Al-15Ce-9Mg alloy. While the elongation of WA-DED Al-15Ce-3Mg is significantly higher, reaching 12.9∼29 %. Significant strain softening occurs during the tensile process due to matrix softening at elevated temperatures. Moreover, WA-DED Al-15Ce-3Mg alloy also shows good high temperature compressive strength, which is 360 MPa at 220 °C, 310 MPa at 250 °C and 240 MPa at 300 °C at the compressive strain of 30 %. For the high temperature creep properties, WA-DED Al-15Ce-3Mg alloy displays higher creep resistance compared to Al-3Mg alloy at similar temperature, and its creep strain accumulates faster as the temperature and stress increase. The dislocation creep are the main creep deformation mechanisms at 220 °C, 250 °C and 300 °C. The dislocation climb controlled by lattice self-diffusion dominates creep deformation at 220 °C and 250 °C, while the dislocation glide is the controlling mechanism for creep at 300 °C. This study demonstrates that WA-DED is an attractive method for fabricating Al-Ce-Mg alloys with a good combination of strength and ductility.