抄録
The fatigue crack growth (FCG) behavior under cyclic loading in TiAl intermetallic and Ti-6Al-4V alloy was investigated at elevated temperature. Crack opening displacement (COD) was measured by using the Laser speckle strain/displacement gage (SSDG) during the fatigue tests. It was found that the FCG rate in TiAl intermetallic at 800℃ was controlled by the effective stress intensity factor range ⊿K_<eff>, while the HCG rate in Ti-6Al-4V alloy above 500℃ was controlled by the maximum stress intensity factor K_<max> as well as ⊿K_<eff>. It was also found that thresholds ⊿K_<eff, th> in TiAl intermetallic at 800℃ were higher than those in Ti-6Al-4V alloy above 500℃
