Study on capturing transformation–thermomechanical behaviour of TRIP steel during impact compression

Abstract

With a strain induced martensitic transformation, transformation induced plasticity (TRIP) steel is expected to show an excellent impact energy absorption characteristic. It is important for an improvement of a reliability of the TRIP steel to evaluate an amount of martensite which can control such good performance of TRIP steel. Here, in order to evaluate experimentally an amount of martensite, it is attempted that volume resistivity, which may change with an amount of martensite, is measured by a circuit based on the Kelvin double bridge under impact deformation using the split Hopkinson pressure bar method. Transient temperature is captured by an extremely thin thermocouple at the same time during the impact test. The experimental results show that volume resistivity of TRIP steel increases, and the temperature rises approximately linearly during impact deformation.

Keywords:

• Strain induced martensitic transformation
• TRIP steel
• Volume resistivity
• Split Hopkinson pressure bar method
• Kelvin double bridge
• Thin thermocouple

The authors gratefully acknowledge financial supports from the Amada Foundation for Metal Work Technology and the SUZUKI Foundation.