Fatigue Crack Propagation in Metastable Titanium Alloys.

Abstract : The fatigue crack growth rate tests of water quenched Corona-5 (Ti-4.5Al-1.5Cr-5Mo) and Ti-6Al-4V alloy were conducted in air at room temperature. The effect of the presence of the metastable retained beta phase on the fatigue crack growth rate was examined in this research. The specimens were heat treated and water quenched to have unstable beta phase that could be transformed to martensite during the fatigue crack growth testing. As quenched specimens were compared with specimens in the mill annealed condition. The fatigue crack growth rates of all the specimens were in the same order of magnitude regardless of the heat treatment. From this research it was shown that in Corona-5 and Ti-6Al-4V alloys the fatigue crack growth rates were not affected by the strain induced martensitic transformation.