Interfacial Creep in Multi-Component Materials Systems

[00:7528 . 11]虽然在许多材料系统中已经注意到界面滑动，但这种现象的清晰的机制还没有出现。这部分与设计实验的困难有关，这些实验允许将界面的应变响应与混淆的叠加效应（如相邻界面的一个或两个组件的蠕变）区分开来。在NSF之前的工作中，已经证明了这一具有挑战性的任务可以通过精心设计的实验和分析方法的结合来完成。目前的研究目标是：(1)开发研究块体和薄膜材料系统界面蠕变的实验和分析方法；(2)通过将滑动动力学与界面形态、结构和化学联系起来，深入了解界面滑动的机理；(3)为选定的具有实际重要性的界面生成滑动动力学数据；(4)评估滑动对两种重要工程系统（纤维复合材料和薄膜-衬底系统）性能的影响。不同材料之间的界面对许多工程材料的性能至关重要。通常，界面处存在较大的剪切应力，并且在使用过程中，连接界面的至少一种材料可以承受较高的同源温度。这会导致扩散调节界面滑动（界面蠕变）的发生，对相关系统的尺寸稳定性和可靠性有潜在的严重影响。可能的例子包括经受热循环的金属基复合材料，服役期间经受焦耳加热或制造期间经受热循环的薄膜微电子器件，以及在开/关循环期间经受热漂移的电力电子封装中的倒装芯片焊点

0075281DuttaAlthough interfacial sliding has been noted in many materials systems, a clear mechanistic picture of the phenomenon is yet to emerge. Part of this is associated with the difficulty of designing experiments which allow the strain response of the interface to be distinguished from obfuscating superimposed effects (such as creep of one or both components adjoining the interface). In previous NSF work, it was demonstrated that this challenging task could be accomplished by a combination of carefully designed experimental and analytical approaches. The current research aims to: (1) develop experimental and analytical approaches to study interfacial creep in both bulk and thin film materials systems; (2) develop mechanistic insight into interfacial sliding by correlating the sliding kinetics with the interfacial morphology, structure and chemistry; (3) generate sliding kinetics data for selected interfaces of practical importance, and (4) evaluate the impact of sliding on the performance of two engineering systems of importance (fibrous composites and film-substrate systems). %%%Interfaces between dissimilar materials are critical to the performance of many engineering materials. Often, large shear stresses exist at the interface, and at least one of the materials adjoining the interface can be subjected to high homologous temperatures during service. This enables diffusionally accommodated interfacial sliding (interfacial creep) to occur, with potentially severe impact on the dimensional stability and reliability of the system of interest. Possible examples include metal-matrix composites subjected to thermal cycling, thin-film microelectronic devices subjected to Joule heating during service or thermal cycling during fabrication, and flip-chip solder joints in power electronic packages subjected to thermal excursions during on/off cycles.***