In situ (Al_3Zr + Al_2O_(3np))/2024A1 metal matrix composite with novel reinforcement distributions fabricated by reaction hot pressing

摘要

In situ hybrid (Al_3Zr + Al_2O_(3np))/2024A1 metal matrix composites with unique controlled reinforcement distributions were fabricated using low energy ball milling and reactive hot pressing. The reaction system between 2024A1 and ZrO_2 was studied using differential thermal analysis (DTA). In situ formed aluminium oxide (Al_2O_3) and zirconium tri-aluminide (Al_3Zr) with varying morphology and sizes were produced under different fabricating conditions. Al_3Zr with varying morphologies such as particle, plate and flakes were observed. With a total 10 vol.% of reinforcements, the composite containing a three-dimensional network of closely spaced in situ synthesized Al_3Zr and Al_2O_3 particles had a YS of 175 MPa and a UTS of 261 MPa, effectively strengthening the 2024A1 matrix. The effect of different sintering conditions on the microstructure and tensile properties of the composite was systematically investigated.