Influence of Temperature on High Cycle Fatigue Properties of Ti-6Al-2Sn- 4Zr-6Mo
ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN MA
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High cycle fatigue data of unnotched Ti-6Al-2Sn-4Zr-6Mo revealed no change in fatigue strength at 900 F compared to room temperature, 400 F, and 700 F. At 1000 F, the decrease in fatigue strength from that at 900 F and below becomes noticeable. At 1200 F the decrease is significant. The fatigue strength- life curve of specimens coated with electroless nickel and diffusion bonded, which were tested at 1000 F, falls midway between results of uncoated specimens tested at 1000 F and 1200 F. Microstructural changes occurring with time, at temperature, indicate a refinement of structure. Fractography reveals three distinct areas an initial radial area which is a mixed mode of quasi-cleavage and intergranular fracture followed by a radial fibrous zone, the result of dimpled fracture and finally a shear lip which occurs by shear fracture.
- Properties of Metals and Alloys