DEFORMATION MECHANISM IN ALLOY USING ATOMISTIC SIMULATION

Abstract

Aim of this dissertation was to develop an atomistic model to study the effect of irradiation on the deformation governing mechanism of metal or its alloys and evaluating their mechanical behaviour during the shear deformation. In this thesis, efforts were made to study the effect of helium nanobubble on the onset of plastic deformation in a single crystal Ni. The onset of plastic deformation was quantified as a function of the orientation of slip planes with shear force, and configuration of helium nanobubbles. Two sets of configurations were generated for helium nanobubble, one with radius fixed but the ratio of He to Ni vacancy was varied, whereas in another configuration the ratio was kept constant and the radius of the nanobubble was varied. From the simulation, it was predicted that irrespective of the orientation of Ni crystal with respect to shear forces, helium nanobubble has a detrimental effect on the mechanical properties of the single crystal Ni. In comparison to the size of helium nanobubble, the higher concentration of helium atoms in the nanobubble have a more detrimental effect on mechanical strength. The focus of nuclear scientists is to develop future generation nuclear reactors as well as to predict the safe lifecycle of existing nuclear structures, which are in use for a long period of time. Helium nanobubbles change the mechanical behavior of underlying nuclear material in a significant manner, results presented in this thesis will help in developing a better understanding about the deformation in irradiated Ni crystal.