Fatigue Crack Growth Retardation After Single-Cycle Peak Overload in Ti-6 Al-4V Titanium Alloy

Fatigue crack growth after single-cycle peak overload was investigated in Ti-6Al-4V sheet. Strain hardening was determined not to be the major controlling mechanism retarding crack growth after peak overload, but instead, strain hardening slightly accelerated crack growth for the case when strain hardening was induced prior to crack initiation. Crack growth after peak overload was characterized by 1 no effect after 20 percent overload a 20 percent increase in maximum stress intensity 2 crack arrest immediately following 70 and 100 percent overloads 3 subsequent retarded crack growth rates after 70 and 100 percent overloads and 4 retardation but no arrest following 50 percent overload.