Analysis of Elevated-Temperature Impact Fractures of Graphite-Reinforced Aluminum Composites.

摘要

Instrumented dynamic three-point bend tests were performed on graphite-fiber-reinforced aluminum composites after rapidly heating the specimens to temperatures between room temperature and 550C. Thornel 50graphite fiber reinforced-202Al casting alloy composites were used. Optical metallography and scanning electron fractography were used to determine the role of the matrix in the fracture process. The 202Al alloy contains a low melting constituent that melts at 548C. Segregation of this constituent to grain boundaries during fabrication of the composite causes eutectic melting after heating to high temperatures (greater than 540C) and hot-short failures.