2024 Fiscal Year Annual Research Report
Fatigue Characterization of Ultrahigh Strength and Ductile Mg-Gd-Y-Zn-Zr Alloy with Hierarchical Anisotropic Nanostructure
| Project/Area Number |
22KF0310
|
|---|
| Research Institution | Kyushu University |
|---|
Principal Investigator |
陳 強 九州大学, 工学研究院, 教授 (30264451)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
CHEN YAO 九州大学, 工学研究院, 外国人特別研究員
|
|---|
| Project Period (FY) |
2023-03-08 – 2025-03-31
|
| Keywords | Mg-RE alloy / Very-high-cycle fatigue / Heat treatment / β' nano-precipitates / Damage accumulation |
|---|
| Outline of Annual Research Achievements |
For the beta prime nanoprecipitates and LPSO co-strengthened Mg-RE alloy, unique oxide nodules are observed as a type of fatigue damage that facilitates crack initiation, differing from typical slip-band structures. The presence of LPSO lamellae and dense distributed beta prime nano-precipitates contributes to the high localization of fatigue damage in the form of oxide nodules. These fatigue-induced oxide nodules form and expand within the soft alpha-Mg layer, but their growth is constrained by the surrounding strong LPSO lamellae, resulting in microcrack nucleation. Ultimately, clusters of microcracks along the LPSO/oxide interface merge along the damage bands, leading to the trans-granular crack initiation. Due to the synergistic effect of the LPSO lamellae and the dense beta prime nanoprecipitates, the fatigue life is accordingly prolonged compared to the LPSO-strengthened Mg-RE alloy. The findings offer valuable insights into the potential for designing and modifying microstructures to enhance the fatigue performance of Mg-RE alloys.
|
