Strain Rate Sensitivity of Ultrafine-Grained CP-Ti Processed by ECAP at Room Temperature
Affiliation of Author(s):
冶金工程学院
Key Words:
中文关键字：1，英文关键字：Ultrafine-grained CP-Ti, Equal-channel Angular Pre
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.
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