Test Method of Transformation Kinetics and Morphology Observation at High Strain Rate
Zhang Wangfeng,Lu Zhengxin,Chen Yumei,Zhu Jinhua
(School of Material Science and Engineering,Xi'an Jiaotong University,Xi'an 710049,China)

Abstract: Test method of transformation kinetics is developed at high strain rate using twin specimens. The transformation kinetics of strainª²induced martensite has been measured and microstructure morphology is also observed at high strain rate for austenitic stainless steel. Experimental results show that transformation volume fraction of martensite at high strain rate is less than that at low strain rate when the strain is less then 9£¥, but is higher than that at low strain rate when the strain is over 9£¥. TEM morphology of the twin specimens at stress plateau stage and martensite section at hardening stage has been observed.
Keywords: strain rate;twin specimen;metastable materials;transformation kinetics