Ultra-Strong High-Temperature Mechanical Properties of an Ultrafine-Grained Eutectic Al-Si Alloy by Mechanical Alloying and Press Forming

A high strength Al-12Si has been prepared through mechanical alloying and press forming without any additional alloy components. The alloy exhibited a high tensile strength of 458 MPa at room temperature and retained excellent tensile properties at elevated temperatures with a UTS of 118 MPa at 350 °C after 1000 h of exposure. Furthermore, after 1000 h of heat exposure testing, the mechanical properties of the alloy showed no significant decrease. X-ray diffraction characterizations indicated that the alloy consists solely of an Al matrix and Si phase. Microstructural characterization through HRTEM revealed that the grain size of the Al matrix was approximately 300 nm, with a high-density of stacking faults present. The grain refinement strengthening and stacking fault strengthening contributed to the alloy’s excellent mechanical properties at both room temperature and elevated temperatures.