2016 Fiscal Year Annual Research Report
超高強度－高延性複層鋼板の開発とその基盤となる組織・界面設計の研究
| Project/Area Number |
15F15705
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| Research Institution | The University of Tokyo |
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Principal Investigator |
小関 敏彦 東京大学, 大学院工学系研究科(工学部), 教授 (70361532)
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| Co-Investigator(Kenkyū-buntansha) |
LIU MAO 東京大学, 大学院工学系研究科(工学部), 外国人特別研究員
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| Project Period (FY) |
2015-11-09 – 2018-03-31
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| Keywords | Crystal plasticity / Phase transformation / Multilayered steel / Plastic deformation / Twinning behavior / Hardening behavior / Indentation / Finite element method |
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| Outline of Annual Research Achievements |
1.My first paper has been accepted and published in the journal “Philosophical Magazine” (M Liu*, S. Nambu, T. Koseki, K. A. Tieu, K. Zhou. Three-dimensional quantification of texture heterogeneity in single-crystal aluminum undergoing equal channel angular pressing. Philosophical Magazine. 2017(97): 799-819), and my second paper is currently under review;
2.I have guided a master student to successfully establish a crystal plasticity finite element method (CPFEM) model predicting the phase transformation mechanism of TRIP steel, and this model is based on the real microstructure of TRIP steel;
3.I have also established a CPFEM model to predict plastic deformation and hardening behavior of multilayered steel;
4.I have conducted some experimental observations about twinning behavior of multilayered steel, and the testes are still ongoing;
5.I have attended an invited talk at King Abdullah University of Science and Technology this year; 6.I have received an invitation to write a paper for a special issue of the journal “Crystal” in terms of indentation hardness of metallic materials by Prof. Ronald W. Armstrong.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
1.I am familiar with numerical simulation and I have hands-on experiences about predicting microstructure evolution and plastic deformation of metallic materials;
2.The reports of applying CPFEM into predicting phase transformation and plastic deformation of multilayered steel is rare, especially for the case that the polycrystalline CPFEM model which is based on the real microstructure of steels due to the fact that : a. steel materials usually contain many different phases and the determination of parameters for different phases is quite complicated; b. BCC structure has 3 sets of slip systems which make the simulation and validation even harder;
3.The uniform strain of martensitic steel is less than 4%, and thus the observation of hardening behavior for martensitic steel at larger strain is impossible. However, by using multilayered steel composed by martensitic steel and TWIP steel, the larger uniform strain (more than 50%) can be achieved and the hardening behavior of multilayered steel component can only be measured by indentation;
4.By using multilayered steel composed by martensitic steel and TWIP steel, good ductility and strength can be obtained spontaneously for the material, and discovering the contribution of twinning behavior to the improved mechanical properties of multilayered steel is interesting and important.
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| Strategy for Future Research Activity |
1.I will continue to do the CPFEM simulation of multilayered steel regarding phase transformation and deformation behavior, and all the simulation will be validated by experimental observations;
2.I will go on doing the experimental tests to observe the twinning behavior of multilayered steel as well as hardening behavior of martensitic component during larger straining via indentation technology;
3.I will analyze all the numerical and experimental data to conduct academic writing and paper submitting.
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