Study of microstructure and mechanical properties of quasi-continuous network structured (Ti3AlC2-Al3Ti)/2024Al composites based on hot rolling

Abstract

To investigate microstructure evolution and improve mechanical properties of quasi-continuous network structured (Ti3AlC2-Al3Ti)/2024Al composites, Hot rolling with entire 40 % deformation under 500 °C was conducted. The results show that rolling deformation refined precipitations in matrix and elongated network structure, causing increment of matrix connectivity and decrement of local reinforcements volume of network structure, as well as activated DRX behavior and caused grain refinement and sub-grain appearance. After rolling deformation, the composites showed an increasing trend in both strength and ductility, the superior properties for as-rolled 5 vol% (Ti3AlC2-Al3Ti)/2024Al composite increased by 38 % in ultimate tensile strength (390 MPa), 29.1 % in yield tensile strength (205 MPa) and almost 1 time in elongation (9.8 %), while for 10 vol% composite was 430 MPa, 232 MPa and 4.3 %, respectively. The increment in ductility of the as-rolled composites results from both DRX behavior and decrement of local reinforcements volume in network structure, while the superior strengthening mechanisms can be mainly attributed to grain refining of matrix, load transfer of reinforcements and thermal mismatch.