MateriAlZ Seminar: Jiyun Kang
Friday, January 12, 2024, 11:00 a.m., Arizona Time
Jiyun Kang
Postdoctoral Scholar in Mechanical Engineering
Stanford University
"In-situ Nanoscale Study of Deformation Heterogeneity in Complex Multi-phase Alloys"
Zoom link | Passcode: 844294
MateriAlZ Seminar website | YouTube | Twitter
Abstract:
The pursuit of high-strength, ductile alloys drives the development of materials with intricate micro/nano-scale hierarchical structures. While this expanding microstructural complexity offers exciting opportunities for alloy design, it also poses challenges in understanding the dynamic interactions among local microstructural attributes. In this presentation, I will introduce a comprehensive correlative approach to advance our understanding of deformation heterogeneity in complex multi-phase alloys. This approach leverages in-situ microscopy, in-situ synchrotron X-ray diffraction, and various mapping techniques to assess microstructure, phase stress, and micro-strain evolution. In the first part of my talk, I will discuss how the local crystallographic configurations of the hexagonal close-packed alpha phase influence strain localization and damage behaviors in a two-phase titanium alloy. I will also highlight the role of mechanical twinning in modifying strain localization and its potential for retarding damage development. In the second part, I will explain how neighborhood phases control the mechanical stability and the local strain-accommodating capability of retained austenite in multi-phase transformation-induced plasticity (TRIP)-assisted steel. Finally, based on the findings, I will discuss micromechanically-guided microstructure design strategies to improve the structural properties of these alloys.
Bio:
Jiyun Kang is a postdoctoral scholar in mechanical engineering at Stanford University since 2023. She earned her PhD in materials science and engineering from MIT in 2022, as well as BS and MS degrees in materials science and engineering from Pohang University of Science and Technology (POSTECH). She is passionate about various aspects of structural materials design and characterization, such as physical metallurgy, cellular solids, nanomaterials, and in-situ mechanical testing. Her research focuses on the development and application of advanced in-situ characterization techniques and analytical methodologies to quantitatively and statistically evaluate the microstructural origins of deformation heterogeneity in metals, thereby guiding the design of high-performance structural alloys.