Collaborative Research: Elucidating the Mechanics of Shear Delocalization in Metallic Glass Matrix Composites

金属玻璃基复合材料是一种将高强度非晶态金属与韧性晶体夹杂物结合在一起的联合收割机。通过结合这两种成分，人们的目标是克服金属玻璃固有的脆性。这些材料具有同时达到高强度和高延展性的巨大潜力。尽管如此，负责金属玻璃基复合材料的性能的机制的确切性质仍然未知。要充分利用金属玻璃基复合材料，就必须充分了解这些机理。本研究结合实验和计算建模来研究这些材料的独特变形行为。它的目标是建立新的变形机制图，这是工程师常用的描述材料特性的工具。这些机制的知识将定义新的方法来控制金属玻璃基复合材料的机械性能。 这将改变结构金属的经典应用空间，并在现代冶金学中开辟令人兴奋的新研究领域。主要调查人员将为代表性不足的大学生提供研究和学习机会。这些学生将被激励去实现他们的个人潜力，同时培养批判性思维能力，学术创造力和对工程的热情。这些活动将在综合计算材料工程approaches.Objective的背景下，这项研究的目的是发展一个新的基本理解的竞争率与剪切带成核和传播在金属玻璃基复合材料和这些力学的应变离域和延展性的影响。指导性假设是，由结晶相引起的延展性是由剪切带传播速率的限制引起的，这反过来又促进了许多剪切带的成核，从而有效地使塑性应变累积的过程离域。为了验证这一假设，这个多方面的研究计划将独特的中尺度剪切转变区动力学模拟与仪器压痕技术相结合，用于研究导致离域的速率竞争以及出现的任何自然长度尺度。通过将速率和机械长度尺度与微观结构变量相关联，将构建新的变形机制图，以阐明离域力学，并制定新的设计方法，使金属玻璃基复合材料的机械性能可调。

Metallic glass matrix composites are a new class of materials that combine high-strength, non-crystalline metals with ductile crystalline inclusions. By combining these two components one aims to overcome the inherent brittleness of metallic glasses. These materials have a tremendous potential to reach both high strength and and high ductility at the same time. Still, the exact nature of the mechanisms responsible for the properties of metallic glass matrix composites remains unknown. A full knowledge of these mechanisms is needed to fully use metallic glass matrix composites. This research combines experiments and computational modeling to study the unique deformation behavior of these materials. It has the goal to build new deformation mechanism maps, a tool commonly used by engineers to depict material properties. Knowledge of these mechanisms will define new methods to control the mechanical properties of metallic glass matrix composites. This will result in the ability to transform the classical application space of structural metals and open up exciting new areas of research in modern metallurgy. The principle investigators will offer research and learning opportunities for underrepresented college students. These students will be motivated to achieve their individual potential while fostering the development of critical thinking skills, academic creativity, and a passion for engineering. Such activities will be in the context of the Integrated Computational Materials Engineering approach.The objective of this research is to develop a new fundamental understanding of competing rates associated with shear band nucleation and propagation in metallic glass matrix composites and the implications of these mechanics for strain delocalization and ductility. The guiding hypothesis is that the ductility induced by the crystalline phase results from the limitation of shear band propagation rates, which in turn promotes the nucleation of many shear bands that effectively delocalizes the process of plastic strain accumulation. To test the hypothesis, this multifaceted research program combines unique mesoscale shear transformation zone dynamics simulations with instrumented indentation techniques for examining the competition of rates leading to delocalization as well as any natural length scales that emerge. By correlating rates and mechanical length scales to microstructural variables, new deformation mechanism maps will be constructed to elucidate the mechanics of delocalization and formulate new design methodologies for enabling tunable mechanical properties in metallic glass matrix composites.