Microstructure evolution analysis for the reaction interface between molybdenum and Kovar acquired by electron beam welding-brazing

Guoqing Chen, Qianxing Yin, Zhibo Dong, Ge Zhang, Yulong Li, Yuxing Zhao, Binggang Zhang, Yongxian Huang

科研成果: 期刊稿件文章同行评审

11 引用 (Scopus)

摘要

A brittle reaction interface in molybdenum/Kovar joint acquired by electron beam welding-brazing, which consisted of three zones, was concretely analyzed with respect to microstructure evolution. Zone A was composed of α-Mo and σ (FeMo) intermetallic that was the origin of brittleness. The eutectoid structure in zone B was identified as α-Fe + μ (Fe3Mo2), indicating a decent ability of plastic deformation. The columnar phase of α-Fe extending into eutectoid structure showed a great tenacity considering quantities of gliding dislocations. Phase transformation in the reaction interface during solidification process was concretely analyzed, suggesting an amorphous area near α-Fe due to the blocking effect for eutectoid R (Fe5Mo3) on further eutectoid reaction between liquid metal and σ (FeMo), and, the subsequently excessive cooling rate. Thermodynamic calculation was conducted to explain the existence of μ (Fe3Mo2) with the absence of δ (MoNi) in zone B. The novel stacking faults and their overlapping were found within the body-centered cubic α-Mo due to the decrease in stacking fault energy of Mo with the addition of Fe atoms. Contrast change in diffraction fringes of twinning structure and new stacking fault caused by overlapping was explained.

源语言英语
文章编号110781
期刊Materials Characterization
171
DOI
出版状态已出版 - 1月 2021
已对外发布

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