Effect of Microstructure on Short Fatigue Crack Growth of α+β Titanium Alloys
Fatigue crack initiation and early stage of crack growth for Ti-6Al-4V and Ti-4.5Al-3V-2Fe-2Mo were investigated on notched specimens. <I>In-situ</I> observation of fatigue cracking processes was made using a fatigue testing machine mounted in a scanning electron microscope. It was found that Ti-4.5Al-3V-2Fe-2Mo alloy with very fine α grains of approximately 2μm exhibited a much higher fatigue strength at 10<sup>7</sup> cycles than Ti-6Al-4V alloy. However, in fatigue life an opposite trend was obtained in the short life regime. The observed fatigue behavior in both the long and short life regimes is discussed in terms of metallurgical factors responsible for the fatigue behavior of the present materials.
- ISIJ international
ISIJ international 39(1), 69-74, 1999-01
The Iron and Steel Institute of Japan