Strain Rate Sensitivity of Ultrafine-Grained CP-Ti Processed by ECAP at Room Temperature

Abstract:

Ultrafine-grained (UFG) commercially pure (CP) Ti with a grain size of about 200 nm was produced by ECAP up to 8 passes using route BC at room temperature. For ECAP processing a proper die set was designed and constructed with an internal channel angle Φ of 120° and an outer arc of curvature Ψ of 20°. Strain rate sensitivity of UFG CP-Ti and CG CP-Ti were investigated by compression tests in the temperature range of 298~673K and strain rate range of 10-4~100s-1 using Gleeble simulator machine. Evolution of the microstructure during compression testing was observed using optical microscopy (OM) and transmission electron microscopy (TEM). Strain rate sensitivity value m of the UFG CP-Ti has been measured and is found to increase with increasing temperature and decreasing strain rate, and is enhanced compared to that of CG CP-Ti. Result of the deformation activation energy determination of UFG CP-Ti indicates that the deformation mechanism in UFG CP-Ti is correlated to the grain boundaries.

• Periodical: Materials Science Forum (Volumes 667-669)
• Pages: 707-712
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.667-669.707
• Online since: December 2010
• Authors: Xiao Yan Liu, Xi Cheng Zhao, Xi Rong Yang
• Keywords: Equal-Channel Angular Pressing (ECAP), Strain Rate Sensitivity (SRS), Ultrafine-Grained CP-Ti

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