The low and high temperature creep properties of the α+β titanium alloy Ti834 have been studied for various levels of applied plastic prestrain. Evidence is shown that the prestrain at room temperature causes the formation of quasi-cleavage facets in a manner described by the Evans–Bache model. These facets are also produced when the material is creep tested at room temperature, although larger areas of faceting are found. The applied prestrain causes a drop in the strain at failure at room temperature due to a high dislocation density inhibiting further movement of dislocations. At high temperature this increase in applied prestrain results in an accelerated creep rate. This is attributed to a number of issues, including increased thermal energy allowing greater dislocation recovery and mobility. Swaged Ti834 material is also considered and is shown to behave similar to highly prestrained material with evidence of strain hardening and reduced cold creep rate.
Mark Whittakera, Paul Jonesa, Cameron Pleydell-Pearcea, David Ruggb, Steve Williamsb
a. Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom
b. Rolls-Royce plc, Moor Lane, Derby DE24 8BJ, United Kingdom
Materials Science and Engineering: A Volume 527, Issues 24-25, 25 September 2010, Pages 6683-6689 doi:10.1016/j.msea.2010.07.008