Nanoscale precipitations in deformed dilute alloying Mg-Zn-Gd alloy

Materials & Design

Zhongchang Wang¹  Hua Huang²  Jinyun Tan³  Guangyin Yuan⁴  Wenjiang Ding⁵  Hongwei Miao⁵  Shihao Fan⁵ 

[1] Corresponding authors at: National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.;International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga s/n, Braga 4715-330, Portugal;Shanghai Innovation Institute for Materials, Shanghai 200444, China;Department of Vascular Surgery, Huashan Hospital of Fudan University, Shanghai 200040, China;National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;

关键词: Magnesium alloy;    Nanoscale precipitation;    Atomic structure;    Orientation;    Phase transition;   

DOI  :  

来源: DOAJ

【 摘 要 】

Nanoscale precipitations in deformed dilute alloying Mg-Zn-RE alloys usually play critical positive roles in mechanical properties, while characterizing them still poses a significant challenge due to their small size and low volume fraction. Here, we conduct a systematic structural analysis of the nanoscale secondary phase particles, including W phase, a small amount of I phase and a handful of Mg3Gd phase, in hot deformed dilute alloying Mg-Zn-Gd alloy by combining atomic-resolution transmission electron microscopy with first-principles calculations. The investigation of atomic structure of nanoscale W phase reveals that the stoichiometric composition of W phase is determined by the quantity of Mg atoms which are replaced by Zn at certain positions. Furthermore, nanoscale W phase, I phase and Mg3Gd phase particles could exhibit certain orientation relationships and coherent or semi-coherent interface with Mg matrix, which contributes to atomic bonding at their interfaces. We also identify a phase transition from Mg3Gd phase to W phase, which is further supported by first-principles calculations showing that Mg3Zn3Gd2 phase is energetically more favorable than Mg3Gd phase. The phase transition between W phase and I phase could also take place during hot deformation and is reversible by absorbing or releasing Zn atoms at the interfacial region.

【 授权许可】

Unknown