A thermodynamic assessment of the Bi–Mg–Sn ternary system

Amounts of segregation at grain boundaries of Mg-0.05at％X (X = Al, Bi, Ca, Ce, Gd, Nd, Y, Zn, Zr) alloys were calculated by using the Hillert's grain boundary phase model. As a result, relatively high grain boundary segregation was obtained in each case of Ca, Ce, Nd, Y and Zn. In addition, the basal plane texture and Erichsen value of the alloys were experimentally investigated, which exhibits a similar tendency to the previous experiments, i.e., the Erichsen value decreases with decreasing basal texture intensity. High-angle annular dark-field STEM (HAADF-STEM) analysis of the Mg-0.4Nd (mass％) and Mg-0.2Y (mass％) sheets elucidated that the uniform grain boundary segregation was detected in Mg-0.4Nd, while the localized and scattered segregation region was observed at grain boundary in Mg-0.2Y. These segregation behaviors were explained by the concept of critical element concentration proposed by Griffiths. An un-recrystallized grain microstructure with high lattice distortion was observed in Mg-0.4Nd in Scanning Electron Microscope -Electron Back-Scatter Diffraction (SEM-EBSD) analysis, which leads to a possibility that the grain boundary segregation of Nd contributes to the suppression of recrystallization during rolling. As the strong correlation was observed between the calculated grain boundary segregation and the experimental basal texture intensity, the amount of grain boundary segregation is a useful parameter for describing basal texture intensity of binary Mg alloys.

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“…Table 1 Interaction parameters used for the grain boundary phase model [19][20][21][22][23][24][25][26][27] .…”

Section: E Wmentioning

confidence: 99%

Relationship between Calculated Segregation, Texture and Room Temperature Formability of Binary Magnesium Alloys

Tachi

Suzuki

Huang

et al. 2021

J. Japan Inst. Metals and Materials

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“…The Sn-58Bi solder exhibits an evident disadvantage which is the coarsening of the microstructure that could result in poor mechanical properties during thermal aging [75] and adding alloy elements could suppress the Bi segregation [59]. The thermodynamic modeling of the Sn-Bi system was carried out firstly by Ohtani and Ishida and Niu et al [76] and the microstructure of the Sn-58Bi solder was typical lamellar eutectic structure made up of alternate-layered white Bi phase and grey Sn phase [24]. Miao and Duh [40] carried out experiments on effect of 1 wt.% Cu addition on the microstructure of the Sn-58Bi solder.…”

Section: Microstructure Of Solder Bulkmentioning

confidence: 99%

Properties and Microstructures of Sn-Bi-X Lead-Free Solders

Yang

Zhang

Liu

et al. 2016

Advances in Materials Science and Engineering

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The Sn-Bi base lead-free solders are proposed as one of the most popular alloys due to the low melting temperature (eutectic point: 139°C) and low cost. However, they are not widely used because of the lower wettability, fatigue resistance, and elongation compared to traditional Sn-Pb solders. So the alloying is considered as an effective way to improve the properties of Sn-Bi solders with the addition of elements (Al, Cu, Zn, Ga, Ag, In, Sb, and rare earth) and nanoparticles. In this paper, the development of Sn-Bi lead-free solders bearing elements and nanoparticles was reviewed. The variation of wettability, melting characteristic, electromigration, mechanical properties, microstructures, intermetallic compounds reaction, and creep behaviors was analyzed systematically, which can provide a reference for investigation of Sn-Bi base solders.

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