2016 Fiscal Year Annual Research Report
Fabrication of Bulk Mg Rod with Ultrafine-Grained Microstructure Utilizing Multi-Pass Caliber-Rolling
Project/Area Number |
16H07078
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Research Institution | Kumamoto University |
Principal Investigator |
イ テギョン 熊本大学, 先進マグネシウム国際研究センター, 助教 (50784089)
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Project Period (FY) |
2016-08-26 – 2018-03-31
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Keywords | plastic deformation / metal / grain refinement / magnesium |
Outline of Annual Research Achievements |
I have successfully applied the multi-pass caliber-rolling (MPCR) process to commericial AZ31 alloy. The fabricated rod possessed fine grains of ~2 um as well as bulk dimension. I performed the MPCR from the first to final (eighth) pass to track the change in microstructures and mechanical properties. Most data have been obtained for these nine samples (i.e., 1- to 8-pass deformed materials as well as the as-received) using a uniaxial tensile test, x-ray diffraction, and electron backscatter diffraction analysis. In contrast to typical severe plastic deformation processes, the present caliber-rolling did not accompany the loss of ductility. Some samples even achieved SIMULTANEOUS strength-ductility improvement compared to the as-received AZ31 alloy. The final material after the 8-pass deformation was fabricated in the form of bulk rod with ~1 m length exhibiting the doubled strength with nearly preserved elongation in comparison to its counterpart. Such mechanical improvements are to be interpreted in terms of texture change, dynamic recovery, and grain-boundary sliding.
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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
The research is following the estabilished schedule very well this year. Nevertheless, there may be little modification to the schedule next year (2017) as the candidate material (i.e., long-period stacking-ordered Mg-Zn-Y alloy) is currently treated as confidential due to patents. I am planning to focus on the current material (i.e., commercial AZ31 combined with the technique of MPCR process) further instead. Please see the section of Planning for the Future Work for details.
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Strategy for Future Research Activity |
1. I got accepted for presentation at Seventh International Conference on Nanomaterials by Severe Plastic Deformation (NanoSPD7) with the research topic supported by the present fund. The title has been confirmed to be 'Microstructural Evolution and Mechanical Improvement of AZ31 Bulk Rod via Multi-Pass Caliber-Rolling Process'. 2. The topic #1 will then be submitted to an international scientific journal by the end of this project. It focuses on the microstructural evolution and resultant mechanical improvements during the MPCR process. 3. Moreover, this year I will start a new research topic to compare low-temperature mechanical properties of 7-pass MPCR-processed and commercial AZ31 alloys. This topic will also be submitted another international scientific journal.
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