Description of Stress-strain Curves Based on Thermal Activation Models for a Ti-Fe-O Alloy at 77 to 296 K with Strain Rates from 10~(-9) to 10~(-2) sec~(-1)

摘要

Using two thermal activation models for dislocation motion, we analyzed experimental data for a Ti-Fe-O alloy. One is the Kocks-Mecking model and the other is the Ogawa model. These two models differ form each other in the determination of thermal stress component and the modeling of work hardening. The Kocks-Mecking model is found to describe well the measured flow curves in a temperature range between 77 and 296 K and in a strain rate range between 10~(-5) and 10~(-2) sec~(_1). The so-called base curve is found to be a flow curve at the strain rate of approximately 10~(-9)sec~(-1) by the calculations using the Kocks-Mecking model. In actual, the strain rate of 10~(-9)sec~(-1) is approximately the minimum strain rate obtained by the crosshead displacement dwell test. The Ogawa model was found to be insufficient to describe the above flow curves for the Ti-Fe-O alloy.