High Temperature Properties and Strengthening Mechanism of (Al11La3+Al2O3)/Al Composite

A (Al11La3+Al2O3)/Al composite was prepared by powder metallurgy process through the in-situ reaction of Al-La2O3. It was found that the high energy ball milling can promote the in-situ reaction and facilitate high-temperature sintering, thus a sufficient in-situ reaction between Al and La2O3 was achieved, and a dense and defect-free material was obtained. The microstructure analysis showed that micro-Al11La3 and nano-Al2O3 particles were uniformly dispersed in the matrix. The room-temperature tensile strength of the composite reached 328 MPa, the elongation was 10.5%, the tensile strength at 350℃ reached 119 MPa, and the elongation was 10.2%. Compared with the traditional Al-Cu-Mg-Ag and Al-Si-Cu-Mg heat-resistant aluminum alloys, the high-temperature tensile strength of the (Al11La3+Al2O3)/Al composite was enhanced by about 20%. The strengthening effect at room temperature may come mainly from the dislocation strengthening and load-transfer strengthening effect of Al11La3 and Al2O3, while the strengthening effect at high temperature may be ascribed to the grain boundary pinning effect of Al2O3 © 2023 Chinese Journal of Materials Research. All rights reserved.