日本金属学会誌

J. Japan Inst. Met. Mater, Vol. 77, No. 10 (2013),
pp. 455-460

Effect of Creep and Cyclic Loading on Pulsating Fatigue Behavior for Various Ti Alloys under Stress Ratio R=0

Gen-ichiro Nagatani1, Rumi Kitazawa1,2,3, Makoto Yoshida4 and Susumu Horibe1

1Department of Modern Mechanical Engineering, Graduate School of Creative Science and Engineering, Waseda University, Tokyo 169-0072
2Japan Society for the Promotion of Science, Tokyo 102-0083
3Japan Aerospace Exploration Agency, Sagamihara 252-5210
4Kagami Memorial Research Institute for Materials Science and Technology, Waseda University, Tokyo 169-0051

Abstract:

It is well known that creep at room temperature remarkably occurs in alpha-Ti alloys. Cyclic creep also appears. Moreover, Ti alloys have different crystal structures and various mechanical properties. Although the cyclic creep behavior and the cyclic softening behavior have been studied, integrated effect of them on fatigue life has not been clarified yet. In this study, fatigue behavior under stress ratio R=0, on Ti alloys of three crystal structures, is investigated. Influence of the cyclic creep and fatigue damage, and influence of the crystal structure to fatigue life are examined. As the results, it is found that as to the alpha-Ti, creep is the dominant damage factor. On the other hand, as to the beta-Ti alloy, fatigue is the dominant damage factor. As to the alpha+beta-Ti alloy, both creep and fatigue are the dominant damage factors (intermediate type). Furthermore, it is found that the area ratio and grain diameter of alpha phase, the spacing between different phases, should influence on cyclic creep strain rate. [doi:10.2320/jinstmet.J2013014]


(Received 2013/2/26)

Keywords:

titanium alloy, fatigue, creep, crystal structure


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