The effect of TiB2 ceramic particles on Portevin–Le Chatelier behavior of TiB2/AlMg metal matrix composites

Metal matrix composites (MMCs) have attracted extensive attention due to their excellent mechanical properties. However, the Portevin–Le Chatelier (PLC) behavior of MMCs considering the interaction of reinforced particles and dislocations is rarely reported. In the present study, the influence of TiB2 ceramic particles on PLC behavior is systematically investigated in a TiB2/AlMg composite. It is found that particles decrease the critical strain of PLC at high strain rate (>0.01 s−1) compared with AlMg alloy, but their difference becomes small with the decrease of strain rate. The dual effects of particles are discussed in terms of dislocation waiting time based on experimental characterizations and theoretical modeling. It is shown that with the presence of particles, the waiting time increases at high strain rate, leading to the decrease of critical strain, but the proportion of additional waiting time induced by particles in overall waiting time gradually decreases with the decrease of strain rate, leading to the weakening of the effect of particles.