Micromechanisms of Monotonic and Cyclic Subcritical Crack Growth in Advanced HighMelting Point Low-Ductility Intermetallics

摘要

The next generation of high-performance engines will require stiffer materials,operating at higher stress levels and capable of with-standing significantly higher temperatures up to 1650 deg C and above. Prime candidates for such applications include ordered intermetallics, ceramics, and composites based on metal, intermetallic and ceramic or carbon matrices. However, these materials are currently of limited use due to their low ductility and toughness properties; moreover, an understanding of their fatigue resistance is still essentially lacking. Accordingly, the present research was aimed at examining one class of these materials, namely ductile-phase toughened intermetallic alloys, with respect to the critical factors influencing crack-propagation resistance under