A strategy for adjusting the microstructure configuration and high temperature mechanical properties of Al–Cu alloys

Lightweight heat-resistance Al alloys are increasingly garnering attention in contemporary research. The Al–Cu series alloys exhibited excellent mechanical properties at high temperature. However, the nano-sized precipitates are prone to coarsening and failure under high temperature, which restricts further breakthroughs in the high temperature performance of alloys. This work utilized Al-TCB master alloy to design and regulate the microstructure and mechanical properties of Al–Cu alloys. Comprehensive analysis revealed that the addition of Al-TCB master alloy refined the grain size, strengthened the second phase at grain boundaries, as well as regulated the size and density of nano-sized precipitates inside grains. Furthermore, it can effectively suppress the coarsening of such precipitates at high temperature, thus achieving excellent strength and ductility. According to microstructure analysis, the aspect ratio of precipitates is substantial. The alloys incorporating Al-TCB master alloy exhibited outstanding tensile property at both room temperature and high temperature (350 °C), achieving the ultimate tensile strength, yield strength, and elongation of 405 MPa, 255 MPa, 15.0 % and 109 MPa, 97 MPa, 9.3 %, respectively. This research can offer a highly promising strategy for the design and manufacture of Al–Cu alloys with high performance at room and high temperature.