Microdeformation of soft particles in metal matrix composites

In this study, microdeformation of soft particles in metal matrix composites was investigated. For that purpose, two different types of ductile iron having different metal matrix microstructures were tensile stressed and compressed. It was found that graphite nodules do not change their shape during tensile stressing, only decohesion occurs on the graphite and metal matrix interface. However, compression testing at room temperature resulted in a significant change in graphite shape. A relationship between average aspect ratio of graphite after various degrees of compression and bulk material deformation was devised. Furthermore, graphite nodule and metal matrix microdeformation was compared to bulk material deformation. This implies that deformation process is not homogenous. It strongly depends on metal matrix microstructure and can be represented with deformation ratio (K). Deformed or deformed and cracked graphite nodules were found on the fractured surface of compressed specimens, indicating that the graphite does not turn into powder during compression at room temperature, as other previous researches found.