2024年4月18日、NIMSにて、The Ohio State UniversityのProf. Yunzhi Wangによるご講演が第152回構材ゼミとして開催されました。
Prof. Yunzhi Wang (The Ohio State University)
BIO｜Prof. Yunzhi Wang
日時：2024年4月18日(月曜日)15:00～16:30
会場：先進構造材料研究棟 5階カンファレンスルーム
開催者：阿部太一
（NIMS構造材料研究センター材料評価分野 組織熱力学グループ）
講演後の集合写真 Prof. Yunzhi Wang（左から５人目）
“Transformation and Deformation Pathway Engineering and Novel Alloy Design Strategies”
Abstract：
In this presentation, we demonstrate novel alloy design strategies inspired by experimental findings and guided by mechanism-based modeling and simulation. Our first example highlights the use of compositional modulations at nano- and micro-meter scales to mitigate autocatalysis and tailor stress-strain behaviors during superelastic and plastic deformations. It is noteworthy that autocatalysis, propelled by long-range elastic interactions, is a critical feature inherent in all shear deformation processes, whether facilitated by dislocations, twinning, structural transformation in crystalline solids, or shear-transformation-zones (STZ) in metallic glasses. This phenomenon leads to strain avalanches and stress plateaus in stress-strain curves. Therefore, effective microstructural engineering is essential to suppress autocatalysis and achieve desired stress-strain behaviors in alloys. In our second example, we illustrate the utilization of mechanically driven localized phase transformations at stacking faults and deformation twin boundaries to design two distinct types of alloys: (a) Ni-base superalloys featuring self-healing g’ precipitates and exceptional creep resistance, and (b) NiTi shape memory alloys exhibiting linear superelasticity, negligible hysteresis, and ultralow Young’s modulus.