Effect of Notch Acuity on the Fracture Toughness of Silicon Carbide/Aluminum Metal Matrix Composites

摘要

Discontinuous silicon carbide/aluminum alloy (SiC/A) metal matrix composites (MMC's) have exhibited improved physical and mechanical properties as compared to the properties of the wrought matrix alloy. These improved properties include high specific modulus, high creep strength, high fatigue resistance, low thermal expansion, and good thermal stability. The SiC/Al composites can be worked using standard metallurgical processing and hence they are inexpensive to produce compared to other MMC systems. The tensile ductility and fracture properties of the composite reported to date, however, are less than those of the wrought alloy. The tensile ductility has been improved by control of process parameters, but relatively little improvement in fracture toughness or notch sensitivity has been achieved. Although the composite materials show limited gross ductility, their fracture behavior exhibits many of the characteristics of ductile fracture.