Shaolou Wei—Tuning nanoscale phase transitions to expand transformation-induced plasticity

Shaolou Wei, a PhD Candidate in the Department of Materials Science and Engineering at MIT, gave the Nano Explorations talk on June 22, 2021. Metals and alloys have been mankind’s most essential structural materials since the Bronze Age. To seek optimal strength-ductility balance in metallic alloys, athermic phase transformations during plastic deformation are regarded as one of the most effective approaches to promote strength while impeding plastic instability incipience. Decades of efforts in ferrous alloy design have documented the significant role of strain-induced martensitic transformation in mechanical performance improvement (namely, the transformation-induced plasticity effect, TRIP). Although it has a mechanical benefit, the resulting transformation product of the TRIP-effect, martensite, can be detrimental. The extensive defect density within the martensitic phase and the hardenability discrepancy with its adjacency can lead to local embrittlement and eventual fracture. Wei’s talk reveals two potential solutions: a sequential martensitic transformation mechanism and a mechanical faulting response. Further insights into mechanistically-guided alloy design is also discussed. -------------------------------------------------------- Nano Explorations is a virtual seminar series powered by MIT.nano that features presentations by MIT students and postdocs on their work in nanoscience, nanotechnology, and other advanced research fields. The series was launched as a way to keep our nano community connected during the COVID-19 pandemic. Presentations take place every other Tuesday at 11am EDT and are open to any interested viewers. Read more about past and upcoming Nano Explorations at mitnano.mit.edu/nano-explorations.