Microstructure and mechanical behaviors of Ti3AlC2 triggered in-situ Al3Ti and TiC reinforced 2024Al composite

Abstract

In this work, 2024Al matrix composite reinforced by in-situ Al3Ti and TiC was fabricated using hot-press sintering Ti3AlC2 and 2024Al powders. The effect of Ti3AlC2 precursor additions (10, 20 and 30 vol.%) on microstructure and mechanical properties of Al3Ti-TiC/2024Al composites were investigated. It was found that Ti3AlC2 decomposed into submicron TiC particles at 950 °C, while Al atoms reacted with Ti to form Al3Ti. In-situ Al3Ti and submicron TiC were homogeneously distributed in 2024Al matrix. The high temperature tensile and compressive behavior of the in-situ Al3Ti-TiC/2024Al composites was tested in the temperature range of 25–400 °C. The results indicated that the tensile and compressive properties of the material showed temperature dependence. The 20 vol.% Ti3AlC2/2024Al composite exhibit a higher tensile yield strength of 368 MPa with a noticeable elongation of 5.4% at room temperature compared to the pure 2024Al (tensile yield strength is 146 MPa with elongation of 8.5%). At 300 and 400 °C, the tensile yield strength of the as-sintered 30 vol.% Ti3AlC2/2024Al composite was determined to be 176 and 126 MPa, increased by 96% and 293%, respectively, compared with that of pure 2024Al alloy. The excellent tensile property of Al3Ti-TiC/2024Al composites can be ascribed to the synergistic strengthening effect in term of dislocation density, load transfer and dispersion strengthening.

Keywords

• 2024Al matrix composites
• Ti3AlC2
• Al3Ti
• TiC
• Microstructure
• High temperature mechanical properties