Loading Rate Sensitivity of Fracture Absorption Energy of Bainitic-Austenitic TRIP Steel

Abstract

Fracture absorption energies of U-notched and pre-cracked samples of a bainitic-austenitic TRIP steel were studied at different loading rates. The results show that the total absorbed energies increase with increasing the loading rate for the two types of samples. For the U-notched samples, both crack initiation and propagation energies exhibit considerably larger values at higher loading rates. However, for the pre-cracked samples, the crack propagation energy increases noticeably with increasing the loading rate, whereas the crack initiation energy does not show an obvious rise with loading rates. These results are discussed in terms of the amount and role of austenite-to-martensite transformation occurring at various loading rates.