The Role of Fracture Toughness in Low-Cycle Fatigue Crack Propagation for High-Strength Alloys

摘要

The trend toward broader application of high-strength structural alloys has increased the potential for failure by low-cycle fatigue crack propagation. There is a significant probability that complex structures will contain undetected cracks remaining from fabrication or that cracks will readily initiate from less severe fabrication defects. Under the repeated application of high stresses imposed on high-strength alloys, such cracks will rapidly grow in low-cycle fatigue. The guard against disastrous failures caused by cracks propagating to terminal fracture, high-strength structural alloys which also possess high levels of fracture resistance have been developed in recent years. The report describes the principal fatigue crack propagation characteristics derived from high fracture toughness and discusses the potential benefits available through the use of high-toughness alloys in cyclically loaded structures. (Author)