Stress-Induced Hydrogen Concentration in Titanium.
Abstract
The changes in hydrogen concentration that accompany application of a stress-gradient were characterized in titanium alloys so that the influence of stress on hydrogen embrittlement can be understood. In situ measurement of hydrogen was made useing the nuclear microprobe for hydrogen (NMH). A nondestructive depth-profiling technique that utilizes the IH(7Li, gamma)8Be resonant nuclear reaction. Stress gradients were applied by four-point bending. Single phase alloys of beta-Ti and alpha-Ti, as well as different alpha/beta morphologies of Ti-6Al-4V alloy, were examined. Hydrogen redistribution was observed in all the beta-phase alloys under an elastic stress gradient, but no further change accompanied plastic deformation. The extent of hydrogen change in high-purity alloys was approximately two times greater than in commercial alloys. Based on this difference and measurements of the partial molal volume of hydrogen in selected alloys, it was concluded that a portion of hydrogen in the commercial alloys was not available for redistribution and was, therefore, trapped. Factors such as hydrogen content, oxygen content, and cold working were not found to change the extent of hydrogen trapping. The practical significance of trapping lies in its possible use to reduce the deleterious influence of hydrogen. The diffusion coefficient in these alloys was also determined under both elastic and plastic loadings and was found to be relatively uniform, approximately 1 time 10 to the minus 6 sq cm. per s, and consistent with those previously reported for beta-Ti.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1981
- Accession Number
- ADA098100
Entities
People
- Philip N. Adler
- Robert L. Schulte
Organizations
- Grumman