金属間化合物TiAl合金の高温疲労機構に果たす複合組織の役割について

概要

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The influence of dual phase on the fatigue reliability of the intermetallic compound TiAl alloy at an elevated temperature was examined through in-situ observation of mesocrack behavior with scanning electron microscope (SEM)-servo testing. The main results obtained were as follows : (1) The fatigua strength ratio, that is strength/density, of intermetallic compound TiAl alloy at 1073K under vacuum is excellent. (2) During most of the fatigue life of the intermetallic compound TiAl alloy, mesocrack growth was observed. Thus, the fine fatigue property of TiAl alloy is due to its higher resistance to mesocrack growth. (3) The effect of dual phase on fatigue crack growth was considerable. In the early stage of fatigue life, plastic deformation was observed in the lamellae structure, it triggered the γ phase brittle cracking. After that, brittle cracks in the γ phase caused shear cracking in the lamellae structure at the medium stage of fatigue life. Many mesocracks that is brittle crack in γ phase and shear cracks in lamellae structure, coalesced with each other into one inacro fatigue crack.
一般社団法人日本機械学会の論文
1997-06-25