Texture-induced anisotropic elastic properties and their temperature dependences in hot-rolled Ti-24Nb-4Zr-8Sn alloy

A superelastic Ti2448 alloy plate was fabricated via hot rolling to investigate its microstructure and superelastic behavior, with a focus on the effects of texture on fully recoverable strain within temperatures between 218 and 383 K. Microstructural analyses of the plate show a single beta phase microstructure with a typical hot-rolled beta texture. It has a strong (110)(beta) along the rolling direction (RD) and a mixture of (111)(beta) and (110)(beta) along the transverse direction (TD). The texture difference results in a larger fully recoverable strain with greater temperature sensitivity in RD compared to TD: the fully recoverable strain increases from 1.2 % to 3.4 % in RD while from 1.1 % to 2.6 % in TD as the testing temperature decreases from 383 K to 218 K. This is explained by the different elastic properties and atomic bonding strengths of the <110> and <111> crystallographic orientations of the beta-phase. We further determine the temperature coefficients of both fully recoverable strain and elastic modulus of different crystallographic orientations of beta-phase through mixture rule modeling. These findings are helpful for optimizing superelastic properties of beta titanium alloys by controlling texture.