1994 Fiscal Year Final Research Report Summary
Multiaxial Low Cycle Fatigue Criterion for Advanced Ni-base Directionally Solidified Superalloy
| Project/Area Number |
05650102
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | RITSUMEIKAN UNIVERSITY |
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Principal Investigator |
SAKANE Masao Faculty of Science and Engineering, Ritsumeikan University, 理工学部, 教授 (20111130)
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| Co-Investigator(Kenkyū-buntansha) |
OHNAMI Masateru Faculty of Science and Engineering, Ritsumeikan University, 理工学部, 教授 (60066587)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Superalloy / Directionally solidified / High temperature / Creep-fatigue / Constitutive relation / Anisotropy of elastic constant |
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| Research Abstract |
This research carried out the tension-torsion multiaxial creep-fatigue test using Rene80H directionally solidified superalloy at 1173K in air. The main conclusions obtained are as follows.
1.Mises strain, maximum principal strain, the equivalent strain based on crack opening displacement and other multiaxial strain parameters proposed so far, all could not correlate the tension-torsion multiaxial low cycle fatigue data of Rene80H directionally solidified superalloy within a factor of ten scatter band. Maximum principal stress and the equivalent stress based on crack opening displacement, on the other hand, correlate those multiaxial data within a factor of two scatter band.
2.A new strain parameter, anisotropic principal strain, was proposed by analyzing the anisotropic stress-strain relation of the superalloy. The anisotropic strain takes account of the anisotropy of Young's modulus of the superalloy and correlated the multiaxial low cycle fatigue data within a factor of two scatter band.
3.The trend of multiaxial creep-fatigue life in multiaxial slow-fast tests is similar to that of low cycle fatigue life in fast-fast tests, whereas the reduction of tension-going strain rate decreases significantly failure life.
4.Crack in torsion test is Mode I but that in tension test is Mode II.The transition of crack mode occurred between the two tests.
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