Dynamic deformation behavior of a high reinforcement content TiB₂/Al composite at high strain rates

Dynamic compressive properties of a 60 vol.% TiB₂/Al composite fabricated by squeeze casting method were measured using split Hopkinson pressure bar. The 60 vol.% TiB₂/Al composite showed significant strain-rate sensitivity compared with the rate insensitive aluminum alloy matrix. The flow stress and the strain-rate sensitivity both showed rise/fall tendency at high strain rates. Moreover, a large plastic strain as 7.8% was obtained at 1850 s^-1. The dynamic compression behavior of high reinforcement content composite was affected mostly by strain-rate strengthening and adiabatic heating softening mechanism at dynamic loading. Adiabatic heating cannot only accelerate the softening and flow of aluminum alloy matrix but also restrain the low-strain failure of high reinforcement content composites. The TiB₂/Al composite exhibited a mixed failure characteristic that consist of cracking of reinforcement particles and ductile fracture of matrix alloy.