Programme

I.3 -- Invited, VCTP-44

Date: Monday, 29 July 2019

Time: 14:00 - 14:30

Physics of Plasticity from Atomistic Views; Defect Mechanics

Yoji Shibutani

Department of Mechanical Engineering, Osaka University

Plasticity stems from the Greek “plaistikos” of forming. Thus, the metals can be plastically deformed by introducing the line defect, called “dislocation”, to obtain the permanent shape of object which has a physical function for the practical application. The dislocation dynamics is the fundamental process of the macroscopic plasticity. Phenomenological plasticity has been academically systematized by the continuum theory, that is, “The Mathematical theory of Plasticity” (R. Hill, 1950). On the other hand, physical plasticity based on the crystallography and elastic theory can be summarized by “Theory of Dislocations” (J. P. Hirth and J. Lothe, 1982). When we link together with the two views over time and length scales, the defect interactions among the point defect such as vacancy and interstitial, the line defect of dislocation, and the planar defect such as grain boundary and surface should be resolved. The talk will be focused on the physical interactions between the defects using the large scale molecular dynamics and the linear elasticity, putting much emphasis on the followings.
(i) Strength and ductility; interaction between dislocation and grain boundary
(ii) Strength, ductility and fracture toughness; interaction among crack, dislocation, and grain boundary.

Presenter: Yoji Shibutani