ＬＰＳＯ相を有する高強度Ｍｇ－Ｚｎ－Ｙ合金の超高サイクル疲労破壊機構の解明

2018 Fiscal Year Annual Research Report

• Project/Area Number: 16F16809
• Research Institution: Kyushu University
• Principal Investigator: 陳 強 九州大学, 工学研究院, 教授 (30264451)
• Co-Investigator(Kenkyū-buntansha): HE CHAO 九州大学, 工学(系)研究科(研究院), 外国人特別研究員
• Project Period (FY): 2016-11-07 – 2019-03-31
• Keywords: Ultrasonic Fatigue / Magnesium Alloy / LPSO Phase / Crack Initiation / Crack Propagation / Very High Cycle Fatigue

Outline of Annual Research Achievements

In the proposed research, high cycle fatigue properties of an as-extruded Mg-10Gd-3Y-0.5Zr alloy was investigated by focusing on its fatigue crack initiation and early propagation behavior. As a result, several important phenomena were elucidated: (1) only basal slip was activated at low cyclic stress amplitude or in high cycle regime; (2) fatigue crack initiated from the slip bands along the basal plane, leading to the formation of cleavage-like facets on the fracture surface; (3) formation of facets around the crack initiation sites consumed a vast majority of the cyclic loadings in high cycle fatigue regime, and (4) small fatigue crack propagation was significantly retarded by local microstructure heterogeneity of neighboring grains. This can be ascribed to the incompatible deformation at low cyclic stresses, resulting in the localization of slip bands within isolated grains.

Research Progress Status

平成30年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

平成30年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] 四川大学/上海交通大学/中国科学院金属研究所(中国)
  • Country Name: CHINA
  • Counterpart Institution: 四川大学/上海交通大学/中国科学院金属研究所
  • # of Other Institutions: 1
• [Journal Article] Small crack initiation and early propagation in an as-extruded Mg-10Gd-3Y-0.5Zr alloy in high cycle fatigue regime (2019)
  • Author(s): He Chao、Shao Xiaohong、Yuan Shucheng、Peng Liming、Wu Yujuan、Wang Qingyuan、Chen Qiang
  • Journal Title: Materials Science and Engineering: A Volume: 744 Pages: 716～723
  • DOI: https://doi.org/10.1016/j.msea.2018.10.015
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Effect of microstructure on small fatigue crack initiation and early propagation behavior in Mg-10Gd-3Y-0.3Zr alloy (2019)
  • Author(s): He Chao、Wu Yujuan、Peng Liming、Su Ning、Chen Qiang、Yuan Shucheng、Liu Yongjie、Wang Qingyuan
  • Journal Title: International Journal of Fatigue Volume: 119 Pages: 311～319
  • DOI: https://doi.org/10.1016/j.ijfatigue.2018.10.002
  • Peer Reviewed / Int'l Joint Research
• [Presentation] 高サイクル疲労における Mg-Gd-Y-Zr 合金押出材の微小き裂挙動 (2018)
  • Author(s): C. HE, X. SHAO, Y. FUKUSHIMA, K. TSUZAKI, Q. WANG, N. SU, X. HENG, Q. ZHAO, L. PENG, Y. WU, Q. CHEN
  • Organizer: 日本機械学会九州支部第 71 期総会講演会