U.S.-Czech Materials Research on Dynamic Embrittlement of Bicrystals

9414328麦克马洪宾夕法尼亚大学的查尔斯·麦克马洪博士和捷克科学院物理研究所的帕维尔·莱伊切克博士共同开展的这项美国-捷克研究项目的主要目标是研究在表面存在可移动元素的条件下，高强度材料中发生的脆性开裂类型。为了做到这一点，研究人员将测量专门准备的Fe-Si合金双晶中的裂纹扩展速度，作为晶界方向的函数。这样做是因为沿边界的扩散速度会随着方向的变化而变化很大。预计结果将产生并验证一个可用于计算裂纹扩展速率的模型。在这个过程中，研究人员还希望建立一种通用的方法来抑制这种类型的破裂。成功应该有助于我们了解合金钢部件的焊缝和各种热变形工艺中与消除应力开裂有关的问题。这个材料研究项目通过使美国和东欧的专家能够结合互补的人才，并在共同感兴趣和能力很强的领域共享研究资源，实现了促进科学知识的计划目标。***

9414328 McMahon The primary objective of this U.S.-Czech research project between Dr. Charles McMahon of the University of Pennsylvania and Dr. Pavel Lejcek of the Institute of Physics of the Czech Academy of Sciences is to study the type of brittle cracking that takes place in high-strength materials under conditions where a mobile element exists on the surface. To do this, the researchers will measure crack-growth rates in specially prepared bicrystals of Fe-Si alloys as a function of direction in the grain boundary. This will be done because the rate of diffusion along a boundary can vary greatly with direction. Results are expected to yield and validate a model useful in calculating the rate of crack advance. In the process, the researchers also hope to establish a general method of inhibiting this type of cracking. Success should contribute to our knowledge of problems associated with stress-relief cracking in welds in alloy-steel components and in various types of hot-deformation processing. This project in materials research fulfills the program objective of advancing scientific knowledge by enabling experts in the United States and Eastern Europe to combine complementary talents and share research resources in areas of strong mutual interest and competence. ***