Evolution of Phases, Microstructure, and Physical Properties of Ti2AlC-Reinforced Ag-Matrix Composites with Elevated Fabrication Temperature

This work investigates the influence of sintering temperature on phase constitution, microstructure, and properties of Ti 2 AlC-reinforcing Ag-based composite. Part of active Al atomic layer in Ti 2 AlC migrates outward under the induction of relatively low sintering temperature (≤  800 °C) and then generates the Ti-Al compounds and TiC. By means of elemental analysis, obvious Ag-Al inter-diffusion is detected at Ag-Ti 2 AlC interface at 900 °C and then Al-deficient layer forms around slightly dissociated Ti 2 AlC particles. At elevated temperature (950 °C), more significant interface diffusion and dissociation accelerate the decomposition and oxidation of Ti 2 AlC and subsequently generate mixture of titanium and aluminum oxides (Ti x O y , Al x O y ). The oxides’ agglomeration and residual Ti 2 AlC lead to form network-like and ravine-like structure. The moderate Ag-Al inter-diffusion slightly increases the resistivity (94.59 × 10 −3 μΩ·m), but contributes to improving the interface bonding and mechanical properties (106 HV hardness, 298.6 MPa tensile strength) of Ag/Ti 2 AlC at 900 °C. However, the severe Ti 2 AlC decomposition and oxides agglomeration account for the significant deduction in electrical conductivity (132.79 × 10 −3 μΩ·m) and mechanical properties (87 HV, 222.3 MPa) at 950 °C. A mechanism is proposed to further understand the phase transition, microstructure evolution, and interface reaction of the Ag/Ti2AlC with the elevated sintering temperature.