Nano-indentation investigation on nano-twinned Cu-Ag alloys with GBAZ segregation

For the sake of comprehending the mechanical mechanisms of nano-twinned (NT) Cu-Ag alloys with grain boundary affect zone (GBAZ) segregation, molecular dynamics (MD) simulations were used to observe its behaviours during the nano-indentation progress. The effect of grain size, alloying atoms (Ag) content as well as twin boundary spacing (TBS) on the deformation behaviours are considered in this investigation. The open visualization tool OVITO is used to directly observe the deformation progress of nanocrystals during nano-indentation. The reaction between lattice dislocations and twin boundaries is recorded and analyzed in detail as the indentation deepens. The simulation results demonstrate a positive correlation between the twin boundary spacing and the occurrence of dislocations. The dislocation rings will appear more effortlessly as the TBSs increase. Meanwhile, it is frequently observed that the face centre cubic (FCC) atoms are transformed into body centre cubic (BCC) atoms. This work will help to seek for novel metal materials with high strength, high ductility and great electrical conductivity.