Grain boundary chemistry and heat treatment effects on the ductile-to-brittle transition behavior of vanadium alloys

[摘要] The ductile-to-brittle transition (DBTT) behavior of vanadium alloys currently being developed for fusion power systems is sensitive to thermo-mechanical processing variables and history. Factors which contribute to this sensitivity are (1) pickup of interstitial impurities such as oxygen, nitrogen and carbon during heat treatments and elevated temperature forming operations, (2) the final grain size achieved, (3) removal of impurities from solid solution due to precipitation reactions, and (4) segregation of impurities to grain boundaries. Previous work on a V-5Cr-5Ti (Heat No. 832394) alloy suggested that sulfur segregation or precipitation during final mill annealing may play a role in determining DBTT behavior. The effect of heat treatment on grain boundary chemistry and Charpy impact behavior was investigated using a production-scale heat of V-4Cr-4Ti (Heat No. 832665). Specimens were examined with Auger electron spectroscopy to characterize grain boundary microchemistry for correlation with Charpy impact test results obtained from one-third size specimens. (C) 1998 Elsevier Science B.V. All rights reserved.

[发布日期] 1998-10-01

[效力级别]  Proceedings Paper