A study of the thermal creep properties of V-4Cr-4Ti was performed using pressurized tube specimens. Creep tubes nominally 4.57 mm OD by 0.25 mm wall thickness were pressurized with high-purity helium gas to mid-wall effective stresses below the uniaxial yield strength. Specimens were heated to 700 and 800C in an ultra-high vacuum furnace and periodically removed to measure the change in OD with a high-precision laser profilometer. The secondary creep rate was found to be power-law dependent on the applied stress with a stress exponent of 3.7 at 700C and 2.7 at 800C. The average activation energy for creep of V-4Cr-4Ti was 299 kJ/mole, which is quite close to the activation energy for self-diffusion in pure vanadium in this temperature regime. The predominant mechanism of creep deformation for the conditions employed in this study is most likely climb assisted dislocation motion.
Revised: July 27, 2010 |
Published: September 1, 2000
Citation
Kurtz R.J., and M.L. Hamilton. 2000.Biaxial Thermal Creep of V-4Cr-4Ti AT 700C and 800C. In Fusion Materials: Semi Annual Progress Report Ending December 31, 1999, edited by Rowcliffe, A.F. 107-110. Washington Dc:US Department of Energy, Office of Fusion Sciences.PNNL-SA-31875.