2012 Fiscal Year Final Research Report
Prediction of the constitutive equation for uniaxial creep of power-law materials through instrumented indentation testing and modeling
| Project/Area Number |
22560660
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical properties of metals
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| Research Institution | Nihon University |
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Principal Investigator |
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| Co-Investigator(Renkei-kenkyūsha) |
高木 秀有 日本大学, 工学部, 専任講師 (40409040)
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| Project Period (FY) |
2010 – 2012
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| Keywords | 力学特性 |
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| Research Abstract |
Indentation creep tests and finite element simulations were performed on a model material to show that a constitutive equation for conventional uniaxial creep can be derived using the instrumented indentation testing technique. Whenthe indentation pressure and the indentation creep rate maintain constant values of Ps and α, respectively, the contours of the equivalent stress and the equivalent plastic strainrate in the region beneath the conical indenter expand according to the increase in the indenter displacement while maintaining the geometrical self-similarity. These findings indicate that a pseudo-steady state deformation takes place around the indenter tip. The representative points exhibiting the creep behavior within the limited region, which actually determines the indenter velocity,is defined as the location where the equivalentstress 〓 is equal to Ps/3.The equivalent plastic strain rate at the correspondingpoint is found to α/3.6 in the case that the creep stress exponent is n=3.0.The stressexponent and the activation energy for creep extracted from the results of Al-5.3mol%Mgsolid-solution alloy and Mg-based dual phase alloy indentation tests are in close agreementwith those of tensile creep tests reported in the literature. In addition, the values for〓and〓 agree well with the values for the applied stress and the corresponding creep ratein tensile creep tests at the same temperature. The above results show not only that thecreep characteristics of advanced materials, which are often available in minute quantities or as small-volume specimens, can be obtained from carefully designed indentation creep tests, but also that the constitutive equation for tensile creep can be predicted with sufficient precision through indentation creep test results.
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Research Products
(24 results)
