An experimental evaluation of microdamage in metal matrix composites by means of a SEM-EPMA technique

An experimental technique is presented by which mechanical damage in materials can be evaluated. It is based on the Electron Probe Micro-Analysis (EPMA) principle, by which certain analytical possibilities of Scanning Electron Microscopy (SEM) are used. The main scope of the study was to apply this technique for the determination of microcracking damage in edge-cracked metal matrix composites (MMCs). Based on earlier studies this investigation has shown that by this technique the microcracking distribution ahead of an edge-crack under tension can be determined with relatively high reliability. To demonstrate this fact two types of MMCs were investigated. The specimens (shaped as dog-bones with an edge-crack) were subjected to slow tensile loading up to their ultimate stress. At this stress the loading process was terminated and the EPMA technique was applied.