Precipitation Behavior of Mg-7Gd-3Y-2Zn-0.5Zr Alloy during Isothermal Aging

Materials

Yonggang Peng¹  Zhiwei Du¹  Ting Li¹  Wei Liu¹  Minglong Ma²  Yongjun Li²  Guoliang Shi²  Jiawei Yuan²  Xinggang Li²  Kui Zhang² 

[1] Guobiao (Beijing) Testing & Certification Co., Ltd., No.2, Xinjiekouwai Street, Xicheng district, Beijing 100088, China;State Key Laboratory of Non-ferrous Metals and Processes, GRIMAT Engineering Institute Co., Ltd., No.11 Xinkedong Street, Huairou district, Beijing 101407, China;

关键词: magnesium alloy;    precipitation;    LPSO;   

DOI  :  10.3390/ma14071737

来源: DOAJ

【 摘 要 】

Precipitate phases in an Mg–7Gd–3Y–2Zn–0.5Zr alloy aged isothermally at 240 °C were examined using high-resolution transmission electron microscopy (TEM) and high-angle annular dark-field scanning TEM. The two types of precipitation sequence that involve Mg–Gd and long period stacking ordered (LPSO) type were found. The LPSO type sequence consisted of the precipitation of γ′′, γ′, 14H-LPSO/18R-LPSO. The Mg–Gd type precipitation sequence involved the formation of β′(b.c.o.) and β1(f.c.c.). The sequence, morphology, distribution, and crystal structure of these precipitates formed during isothermal aging were investigated. The results indicated that the priority precipitation of Mg–Gd and LPSO type sequences during aging can be affected by Nd, which has a higher diffusion coefficient than Gd and Y. The dislocation structures and strengthening mechanism were also discussed.

【 授权许可】

Unknown