Workshop Summary: Hydrogen Embrittlement

Abstract

The first of the two workshops on hydrogen effects focused on examining four basic questions related to hydrogen. It was hoped that by concentrating our efforts and bringing to bear inputs and expertise from the diverse group of participants present at least a partial resolution to some of these fundamental issues could be achieved. The questions addressed included:

• 1. Can interaction (binding) energies of hydrogen to specific structural features (voids, interfaces, dislocations, etc.) be calculated by chemical and/or physical approaches? How valuable would such information be?

• 2. Hydrogen strongly affects the mechanical (and physical) behavior of a broad range of metals and alloys of different crystal structures, strength, toughness and hydrogen solubility and diffusivity. What differentiates hydrogen from other “embrittling” solutes which are usually more system specific?

• 3. Are hydrogen embrittling effects dominated, in general, by decohesion (cleavage) or plasticity controlled processes?

• 4. Most modeling approaches to hydrogen (or other environmental) embrittlement rely on coupling a kinetic analysis or permeability to the effect of local stress states on hydrogen distribution or redistribution. Can we do better?