In situ (Al3Zr + Al2O3np)/2024Al metal matrix composite with novel reinforcement distributions fabricated by reaction hot pressing

• (Al3Zr + Al2O3np)/2024Al MMC with a novel network distribution was tailored.
• Al3Zr and Al2O3np were in situ synthesized at 740 °C using the 2024Al–ZrO2 system.
• The effect of sintering parameters on Al3Zr morphology was investigated.
• Influence of Al3Zr morphology on tensile properties of the composite was studied.

In situ hybrid (Al3Zr + Al2O3np)/2024Al metal matrix composites with unique controlled reinforcement distributions were fabricated using low energy ball milling and reactive hot pressing. The reaction system between 2024Al and ZrO2 was studied using differential thermal analysis (DTA). In situ formed aluminium oxide (Al2O3) and zirconium tri-aluminide (Al3Zr) with varying morphology and sizes were produced under different fabricating conditions. Al3Zr 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 Al3Zr and Al2O3 particles had a YS of 175 MPa and a UTS of 261 MPa, effectively strengthening the 2024Al matrix. The effect of different sintering conditions on the microstructure and tensile properties of the composite was systematically investigated.