Temperature dependence of the yield stress of metallic nano-sized crystals

Abstract

It is shown that the temperature effect on the variance of local shear stresses is the main factor pre-determining the temperature law of the yield stress of nano-sized crystals. The results of molecular dynamics simulations of uniaxial tension of Mo, α-Fe and W nanowires in three crystallographic directions ([100], [110] and [111]) over the temperature range 100–1000 K are presented. It is found that within this temperature range, the yield stress of nano-sized crystals varies not exponentially, as for bulk single crystals, but is a parabolic function of temperature.

Keywords:

• nano-sized crystals
• yield criteria
• temperature dependence
• atomic thermal vibration
• lattice instability