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

这个由宾夕法尼亚大学的Charles McMahon博士和捷克科学院物理研究所的Pavel Lejcek博士合作的美国-捷克研究项目的主要目标是研究高强度材料在表面存在可移动元素的条件下发生的脆性开裂类型。为了做到这一点，研究人员将测量特殊制备的铁硅合金双晶的裂纹生长速率，作为晶界方向的函数。这样做是因为沿边界的扩散速率随方向变化很大。研究结果有望产生并验证一个用于计算裂纹扩展速率的模型。在此过程中，研究人员还希望建立一种抑制这种裂缝的通用方法。成功应该有助于我们了解在合金钢部件和各种类型的热变形加工中与焊缝应力释放开裂相关的问题。该材料研究项目通过使美国和东欧的专家在共同感兴趣和能力强的领域结合互补的人才和共享研究资源，实现了推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. ***