Enhancement of Fatigue Crack Growth and Fracture Resistance in Ti-6Al-4V and Ti-6Al-6V-2Sn Through Microstructural Modification.

摘要

Significant enhancement of fatigue crack propagation resistance and plan-strain fracture toughness was obtained in commercial-purity Ti-6Al-4V and Ti-6Al-6V-2Sn by microstructural modification. These alloys were studied in 25.4-mm-thick plates with interstitial oxygen contents of 0.20and 0.17weight percent,respectively. Heat treatments were chosen to provide widely varied microstructures;they were a mill anneal, a recrystallization anneal,and a beta anneal. The beta anneal was found to be best for improving the crack tolerance properties in question,but it reduced yield strength 9-14% from levels associated with the original mill anneal. The recrystallization anneal significantly enhanced plane-strain fracture toughness and marginally improved fatigue crack propagation resistance with negligible loss of yield strength. (Author)