CAREER: Interface Engineered Amorphous Alloys for Thermoplastic Forming of Ductile Bulk Metallic Glasses

金属玻璃已经发展成为一种新型的高强度工程材料，对航空航天、电子和汽车工业具有极大的好处。然而，由于张力局部失效的倾向以及批量生产的加工路线有限，它们的技术实用性受到了阻碍。该学院早期职业发展(CALEAR)奖支持设计非晶态合金结构的研究，这些结构具有增强的延展性和成形性，用于生产大块金属玻璃薄板。变形行为及其对微观结构变量的依赖将通过协同计算和实验研究活动来阐明。界面工程化大块金属玻璃板材将首次通过添加剂喷射制造来合成，这将为热塑性成形金属玻璃部件的设计和生产提供无数新的机会。研究活动被纳入新的教育倡议，促进代表人数不足的学生参与少数族裔参与方案，为工程专业提供丰富的课程，并促进建立与地区高中衔接的可持续机制。该职业奖支持基础研究，以了解界面工程非晶态合金中应变离域的机制，该界面工程非晶态合金包含过剩自由体积的晶间区域。引导性假设是，金属玻璃中的剪切局部化可以被多余的自由体积区域打断，这些区域促进了许多亚临界剪切带的分布形核，从而通过消除主导的剪切前沿而产生更均匀的塑性响应。该研究小组将结合界面工程非晶合金的先进表征和纳米机械测试，共同进行剪切局部化的分子动力学模拟，以阐明界面结构和非晶晶尺寸在应变离域机制中的作用。添加剂喷射制造方面的创新将被设计成能够通过分布的微塑性有效地分散塑性应变积累的变型微结构。这项研究的一个主要社会影响是能够通过添加剂喷射制造来生产延展性非晶合金板材，这种板材可以用于金属板材行业的革命，以及通过净形状热塑性成形工艺生产大块金属玻璃部件。

Metallic glasses have evolved into a new class of high-strength engineering materials with compelling benefits for the aerospace, electronics, and automotive industries. However, their technological utility has been hindered by a propensity for localized failure in tension and limited processing routes for bulk production. This Faculty Early Career Development (CAREER) award supports research to engineer amorphous alloys structures with enhanced ductility and formability for the production of bulk metallic glass sheets. Deformation behavior and its dependence on microstructural variables will be elucidated through synergistic computational and experimental research activities. For the first time, interface engineered bulk metallic glass sheets will be synthesized through additive spray manufacturing, which will provide a myriad of new opportunities for the design and production of metallic glass components through thermoplastic forming. Research activities are integrated into new educational initiatives that advance the engagement of underrepresented students in minority participation programs, provide curriculum enrichment for engineering majors, and facilitate the establishment of a sustainable mechanism for interfacing with regional high schools. This CAREER award supports fundamental research to understand the mechanisms underpinning strain delocalization in interface engineered amorphous alloys containing intergranular regions of excess free volume. The guiding hypothesis is shear localization in metallic glasses can be interrupted by regions of excess free volume that promote the distributed nucleation of many subcritical shear bands, thus producing a more homogenous plastic response via elimination of a dominant shear front. The research team will perform molecular dynamics simulations of shear localization collectively with advanced characterization and nanomechanical testing of interface engineered amorphous alloys to elucidate the role of interfacial structure and amorphous grain size in the mechanics of strain delocalization. Innovations in additive spray manufacturing will be devised to enable transformational microstructures that effectively delocalize the accumulation of plastic strain via distributed microplasticity. A chief societal impact of this research is the ability to produce ductile amorphous alloy sheets via additive spray manufacturing that can be used to revolutionize the sheet metal industry as well as produce bulk metallic glass components through net-shape thermoplastic forming processes.