Nanoscale deformation twinning at ultrahigh strain rates during kinetic spraying of nickel

Abstract: Nanoscale twins parallel to the {111} planes were observed to be formed by deformation twinning in a nano-sized grain during kinetic spraying of nickel (>99.5% purity) at ultrahigh strain rates (>107 s−1), high strain levels (>100%) and high temperatures (>873K). An interfacial region dominated by strain hardening over thermal softening upon impact, as shown by finite element simulations, is considered to facilitate twinning with the aid of the effects of small amounts of solute atoms and nanocrystalline/amorphous nickel oxides trapped at local interfaces. [Copyright &y& Elsevier]