Relationship between deformation and stability switching in amorphous metal : Local lattice instability analysis

Computational Plasticity XI - Fundamentals and Applications, COMPLAS XI
  • Masaomi Nishimura
  • ,
  • Kisaragi Yashiro
  • ,
  • Masahiro Arai


We have attempted to comprehend the deformation behavior of amorphous metals by the local lattice instability analysis that discusses the positiveness of atomic elastic stiffness coefficients, B ij α, or the second-order derivatives of atomic energy composition. In the present study, we discuss the stability-switching, or transitions between detB ij α≥ 0 and detB ij α< 0, by the "probabilistic" fluctuation and the "deterministic" mechanical load. No-load equilibrium, tension, compression and simple shear are performed on an amorphous nickel by molecular dynamics simulations. The positive and negative stability-switching, or "stabilization" and "destabilization", occur due to the "probabilistic" fluctuation even at the equilibrium state. The number of detB ij α< 0 atoms shows almost constant while the distribution of detB ij α< 0 atoms indicates different morphology at each observation time. Ratios of switched atoms with stability-switching under tension, compression and shear are larger than that under the equilibrium because the local structural relaxation produces simultaneously both positive and negative stabilityswitching. Atoms with negative and positive stabi