Microplasticity Near Reinforcements

9527751 Mortensen这项研究使用先前美国国家科学基金会拨款开发的技术来研究嵌入在受均匀远场应力的弹塑性材料中的夹杂物附近的微塑性。该计划使用氯化银(AgCl)作为模型材料，用于研究含有大于一微米大小的增强体或夹杂物的金属。AgCl是一种离子固体，它通过位错滑移而变形，从这一点来看，它与金属的相似性是很好的。与金属不同，AgCl是透明的，应力双折射，并允许通过在常温下用金属银装饰来观察低密度的位错。将所得数据与现有的两相材料变形行为模型--EShelby等效夹杂方法和有限元技术进行了定量比较。模型的经验结果和预测之间的差异，如果有的话，有助于指导将微观结构特征和位错力学纳入未来模型的努力。这项研究提供了微观尺度和大块材料中的实验微机械数据，这些数据是在公认的金属模拟中采样的。这项工作的结果与广泛的工程结构材料有关，包括两相合金和金属基复合材料。***

9527751 Mortensen This research uses techniques developed under a prior NSF grant to study microplasticity near inclusions embedded in an elastoplastic material subjected to a uniform far-field stresses. The program employs silver chloride (AgCl) as a model material for the study of metals containing reinforcements or inclusions larger than a micrometer in size. AgCl is an ionic solid which deforms by dislocation slip and its similarity with a metal from that standpoint is well established. Unlike a metal, AgCl is transparent, stress birefringent, and allows for the observation of dislocations at low densities by ambient-temperature decoration with metallic silver. Data are quantitatively compared with two existing models for the deformation behavior of two-phase materials, the Eshelby equivalent inclusion method and finite element techniques. The differences, if any, between the empirical results and the predictions of the models help guide efforts to incorporate microstructural features and dislocation mechanics into future models. %%% This study provides experimental micromechanical data, sampled within a well-established metal analog, at a microscopic scale and within bulk material. Results from this work are relevant to a wide array of engineering structural materials, including two-phase alloys and metal- matrix composites. ***