Development of Mechanical Deformation Mode Map by Generalized Planar Fault Energy for FCC Metals

Abstract

Recently, it has been revealed that intragranular deformation mechanism for FCC crystalline metals cannot be described in terms of the absolute value of stacking fault energy only. The generalized planar fault energy curve containing both stable and unstable energy barriers is required to obtain correct interpretation of deformation mechanism. However, little is known about quantitative relationship between the generalized planar fault energy curve and the deformation mechanism. In this work, we develop intragranular deformation mode map which determine the preferential deformation mode among slip, stacking fault, and twin during plastic deformation. The criterions constructing the map are devised from the directionality of each deformation mode. The validity of the map is confirmed with molecular dynamics for FCC crystals. Our results show that the intragranular deformation mode map can be used to interpret the deformation-related phenomena in more profound level which enables us to design a material with desired mechanical property by a systematical manner, avoiding empirical trial and error methods.