A coupled theory for diffusion of hydrogen and large elastic-plastic deformations of metals

A thermodynamically-consistent coupled-theory which accounts for diffusion of hydrogen, trapping of hydrogen, diffusion of heat, and large elastic-plastic deformations of metals is developed. Our theoretical framework places the widely-used notion of an "equilibrium" between hydrogen residing in normal interstitial lattice sites and hydrogen trapped at microstructural defects, within a thermodynamically-consistent framework. The theory has been numerically implemented in a finite element program. Using the numerical capability we study two important problems. First, we show the importance of using a prescribed chemical potential boundary condition in modeling the boundary between a metal system and a hydrogen atmosphere at a given partial pressure and temperature; specifically, we perform simulations using this boundary condition and compare our simulations to those in the published literature. Secondly, the effects of hydrogen on the plastic deformation of metals is studied through simulations of plane-strain tensile deformation and three-point bending of U-Notched specimens. Our simulations on the effects of hydrogen on three-point bending of U-notched specimens are shown to be in good qualitative agreement with published experiments.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2012

Author dc:creator

• Di Leo, Claudio V

Advisor dc:contributor.advisor

• Lallit Anand.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/74460

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/74460