2017 Fiscal Year Annual Research Report
Characterization of deformation microstructure of Mg alloys containing LPSO structure via transmission electron microscopy
| Project/Area Number |
17F17732
|
|---|
| Research Institution | Kyushu University |
|---|
Principal Investigator |
陳 強 九州大学, 工学研究院, 教授 (30264451)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SHAO XIAO-HONG 九州大学, 工学(系)研究科(研究院), 外国人特別研究員
|
|---|
| Project Period (FY) |
2017-10-13 – 2020-03-31
|
| Keywords | Fatigue Mechanism / Microstructure / Magnesium Alloy / LPSO Phase / Characterization |
|---|
| Outline of Annual Research Achievements |
It is well known that the deformation modes and deformation texture of LPSO reinforced Mg alloys are significantly different from the Mg alloys free of LPSO structures. The severe strain localization thus should be closely linked to the LPSO phase, dislocations, deformation kink, and deformation twins. Slip bands, LPSO-matrix interface, kink boundaries, and twin boundaries are all possible fatigue crack initiation sites. Further, crack may propagate along above-mentioned interfaces, in matrix, or in LPSO structures, or be blocked by these interfaces. The present work is focused on the clarification of dominated crack initiation and propagation mechanism so as to improve fatigue damage resistance of the magnesium alloys via designing microstructure.
|
| 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. Strong interactions between LPSO structures and deformation twins were systematically characterized.
2. Solute atoms segregation along deformation-induced interfaces was detected in Mg-LPSO alloys.
3. The fatigue crack site was detected to be along basal plane, other than twin boundary, in single phase Mg-RE alloy, which will advance our further understanding of fatigue mechanism of Mg-LPSO alloy.
|
| Strategy for Future Research Activity |
1. In order to understand the fatigue behavior of Mg-LPSO phase, we will identify the possible crack nucleation sites and investigate the possible crack evolution mechanisms in Mg-LPSO alloy through SEM and TEM, where the basal plane, LPSO-Mg interface, and twin boundary would be focused on.
2. Possible solute atoms redistribution during fatigue test would be expected due to the cyclic load, and will be elucidated based on the unique deformation process.
3. To highlight the effect of LPSO phases on fatigue behavior of Mg alloys, we will further systematically investigate the different fatigue mechanism, including the nucleation sites and crack propagation, for single phase Mg-RE alloy and Mg-LPSO alloy.
|
