Details

Autor(en) / Beteiligte

• Miao, Hongwei
• Huang, Hua
• Fan, Shihao
• Tan, Jinyun
• Wang, Zhongchang
• Ding, Wenjiang
• Yuan, Guangyin

Titel

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

Ist Teil von

• Materials & design, 2020-11, Vol.196, p.109122, Article 109122

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2020

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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. [Display omitted] •Nanoscale precipitations in high performance Mg-Zn-Gd alloy are systematically studied by atomic-resolution TEM/STEM.•The precise position of Zn and Gd atoms in the unit cell of the nanoscale W phase is determined.•Coherent or semi-coherent interface of nanoscale particles with Mg is identified with certain orientation relationships.•Nanoscale Mg3Gd phase is likely to transform to W phase according to STEM-EDS and first-principles calculation results.