Microstructure and mechanical properties of Ti/Al3Ti metal-intermetallic laminate (MIL) composites with different ductile phase volume fractions prepared by hot-pressing

In this research, Ti/Al3Ti/Al Metal-Intermetallic Laminate (MIL) composites featuring various residual aluminium volume fractions (RAVFs) were manufactured using the vacuum hot-pressing technique. The microstructure, elemental diffusion behavior, and grain characteristics of the Ti/Al interface were systematically investigated. The effect of the RAVF on both the macroscopic and microscopic mechanical properties of the Ti/ Al3Ti/Al MIL composites was systematically examined through indentation and static tensile testing. The thickness and average grain size of the Al3Ti layer increase with a rise in hot-pressing temperature, while the RAVF diminishes significantly. Notably, the nucleation density of Al3Ti was found to be higher at Ti/Al3Ti interfaces compared to Al/Al3Ti interfaces. Furthermore, in the high RAVF (44 %-25 %) specimens, the tensile strength was significantly enhanced with the increasing thickness of the Al3Ti layer. Conversely, in specimens with low RAVF (16 %-4 %), the interaction between the increasing thickness of the Al3Ti layer, the generation of microvoids and cracks, and the weakened coordination of deformation at the interfaces ultimately leads to a reduction of tensile strength. The specimen with the RAVF of 38 % showed superior strength and satisfactory elongation with a strength of 601 MPa and an elongation of 4.6 %. This study reveals the relationship between the volume fraction of ductile phases, interfacial microstructural features, and macroscopic mechanical properties of laminated composites, providing ideas for optimizing their mechanical properties.