Design of a\nThermally Stable Heat-Resistant (Al<sub>2</sub>O<sub>3</sub>+Al<sub>3</sub>Ti)/Al Composite with Excellent\nHigh-Temperature Mechanical Properties: Multimechanism Synergistic\nStrengthening Strategy

The effectiveness of the room-temperature strengthening\nstrategy\nfor aluminum (Al) is compromised at increased temperatures due to\ngrain and precipitate phase coarsening. Overcoming the heightened\nactivity of grain boundaries and dislocations poses a significant\nchallenge in enhancing the high-temperature strength through traditional\nprecipitation strengthening. This study presents novel strengthening\nstrategies that integrate intergranular reinforcements, intragranular\nreinforcements, refined grain, and stacking faults within an (Al<sub>2</sub>O<sub>3</sub>+Al<sub>3</sub>Ti)/Al composite prepared using\nsol–gel and powder metallurgy technology. Excellent high-temperature\ntensile properties are achieved; also, a remarkable fatigue performance\nat increased temperatures that surpasses those of other existing Al\nalloys and composites is revealed. These superior characteristics\ncan be attributed to its exceptionally stable microstructure and the\nsynergistic strengthening mechanisms mentioned above. This work offers\nnew insights into designing and fabricating thermally stable Al matrix\ncomposites for high-temperature applications.