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. ***
