Austenite Stability and Strain Localization in Q&P Steels Deformed at Dynamic Strain Rates скачать в хорошем качестве

Austenite Stability and Strain Localization in Q&P Steels Deformed at Dynamic Strain Rates

Presented at MS&T20 Virtual, 2-6 November 2020 CHris Finfrock, Trevor Ballard, Diptak Bhattacharya, Gus Becker, John Copley, Ben Ellyson, Melissa Thrun, Jonah Klemm-Toole, Amy Clarke, Kester Clarke, Colorado School of Mines Successful application of the quenching and partitioning (Q&P) process using commercial production equipment has led to promising combinations of strength and ductility. This noteworthy mechanical performance is caused by the TRIP effect, whereby the deformation induced transformation of austenite to martensite suppresses strain localization. Predicting the deformation response of Q&P steels at the dynamic rates reached during stamping operations and crash scenarios remains a significant challenge, because the austenite transformation is inherently sensitive to temperature, strain rate, and strain path. Recent studies have reported variations in toughness at elevated strain rates and temperatures. To determine the cause of this behavior, interrupted mechanical testing and synchrotron experiments were performed, to quantify the extent of the austenite transformation over a range of strain rates and temperatures. In this talk, potential causes for the shift in deformation behavior, such as strain rate sensitivity and adiabatic heat accumulation, are evaluated in the context of the martensite transformation.