Effect of temperature on microstructural stabilization and mechanical properties in the dynamic testing of nanocrystalline pure Ti

Commercial purity (CP) Ti was processed by a two-step procedure of ECAP and drawing to give a nanocrystalline (NC) grain size of ~90 nm. Samples were tested in compression at a strain rate of 10 s−1 over the temperature range of 298−673 K. The results show the high stored energy and high interface energy promote the process of static recrystallization (SRX) when the NC Ti is heated above 573 K. Migration dynamic recrystallization (m-DRX) operates during compressive deformation at temperatures of 298−573 K giving a homogeneous microstructure. The compressive yield strength and peak stress at 298 K were measured as 1230 and 1330 MPa, respectively. When the test temperature is increased from 298 to 673 K, the yield strength and peak stress decrease and the work hardening rate and dynamic softening rate are also reduced.