Molecular dynamics study of BNNS/Al composites under compression

Although BNNS/Al composites have been proved to have excellent mechanical properties compared to nanocrystalline Al, the effect of strain rate on the compressive performance of BNNS/Al composites is rarely studied. In this paper, molecular dynamics (MD) simulations were conducted to obtain the mechanical properties of the BNNS/Al model under compression at different strain rates from $10^{-5}$/ps to $10^{-2}$/ps. The results show that the ultimate stress and critical strain of BNNS/Al composites increase at the high strain rate. However, Young’s modulus is independent of strain rate. In the plastic region, the strain energy increases due to the improved strain rate, which indicates the hardening of the composites. This can be explained by the phase transition and dislocation density. The accumulation of dislocations prevents plastic deformation of the Al matrix at the strain rate of 10
²
/ps, resulting in a failure to release energy. In addition, the stacking faults and dislocation density have a significant enhancement as the strain rate increases.