The influence of the slip mode on the microstructure evolution and compressive flow behavior at different strains in an extruded dilute Mg−0.5Bi−0.5Sn−0.5Mn alloy was analyzed through electron backscatter diffraction,...The influence of the slip mode on the microstructure evolution and compressive flow behavior at different strains in an extruded dilute Mg−0.5Bi−0.5Sn−0.5Mn alloy was analyzed through electron backscatter diffraction,X-ray diffraction,transmission electron microscopy,and hot compression tests.The results showed that at a low strain of 0.05,the basal,pyramidaland<c+a>slip modes were simultaneously activated.Nevertheless,at the middle stage of deformation(strain of 0.1,0.2 and 0.5),theslip mode was difficult to be activated and<c+a>slip mode became dominant.The deformation process between strains of 0.2 and 0.5 was primarily characterized by the softening effect resulting from the simultaneous occurrence of continuous dynamic recrystallization and discontinuous dynamic recrystallization.Ultimately,at strain of 0.8,a dynamic equilibrium was established,with the flow stress remaining constant due to the interplay between the dynamic softening brought about by discontinuous dynamic recrystallization and the work-hardening effect induced by the activation of the basalslip mode.展开更多
The effect of the liquid-liquid structure transition(L-LST) on the solidification behaviors and morphologies of Sn-Bi alloys was studied further. The results show that the undercooling of the primary and eutectic phas...The effect of the liquid-liquid structure transition(L-LST) on the solidification behaviors and morphologies of Sn-Bi alloys was studied further. The results show that the undercooling of the primary and eutectic phase increases and the microstructure becomes finer after solidifying from the melt experiencing the L-LST. In the meantime, in hypoeutectic alloy, when solidifying from the melt experiencing the L-LST, the morphology of primary phase changes from the fir-tree crystal into the equiaxed crystal, and less primary phase and more eutectic structure are observed. Moreover, in eutectic alloy, the spacing of eutectic phase decreases markedly. These investigations would be beneficial to further exploration of the correlation between the melt structure and the micro mechanism of solidification.展开更多
The surface tension of a promising lead-free solder Au-Bi-Sn alloys was investigated both by the sessile-drop method and calculation. Experimental measurements were carried out for two cross-sections with the constant...The surface tension of a promising lead-free solder Au-Bi-Sn alloys was investigated both by the sessile-drop method and calculation. Experimental measurements were carried out for two cross-sections with the constant gold to bismuth ration of 1:1 and 1:2. For all the investigated compositions, decrease of the surface tension is observed with increasing temperature. Meanwhile, the surface tension values were also calculated based on Butler’s equation, with using the newest research on thermodynamics data of Au-Bi-Sn ternary system. Compared with the experimental results, a good agreement was obtained.展开更多
The goal of the present work is to investigate the effects of the addition of Sb (0, 3 and 6 wt%) on structure, melting, corrosion and mechanical properties of Sn-Bi eutectic solder alloys. The mechanical properties o...The goal of the present work is to investigate the effects of the addition of Sb (0, 3 and 6 wt%) on structure, melting, corrosion and mechanical properties of Sn-Bi eutectic solder alloys. The mechanical properties of the bulk Sn-Bi-Sb solders were higher as the amount of antimony increases, making compressive strength augment from 65 MPa to 100 MPa when 6 wt% Sb was incorporated to the Sn-Bi eutectic alloy. The three alloys presented a melting temperature that is smaller to the one exhibited by the eutectic alloy Sn-38Pb (Tm = 183°C). According to the electrochemical results, the addition of higher contents of Sb to the Sn-Bi eutectic alloy had a positive effect: it ennobled the Ecorr values.展开更多
The stray crystals seriously affect the properties of metals which fabricated by directional solidification(DS). In order to observe the formation of the stray crystals, the growth behavior of Sn-10 wt.%Bi alloy was o...The stray crystals seriously affect the properties of metals which fabricated by directional solidification(DS). In order to observe the formation of the stray crystals, the growth behavior of Sn-10 wt.%Bi alloy was observed by synchrotron X-ray imaging technique using self-developed directional solidification(DS) apparatus. The experimental results show that Sn–10 wt.%Bi alloy is oriented with the form of dendrites to grow into the liquid phase during the DS process, and dendrites are arranged neatly to form columnar crystal microstructures. It is also found that parts of the dendrite arms begin to crack. These cracked dendrites drift upward to grow up in front of the solid-liquid interface and form stray crystals.展开更多
Ag-Sn-Cu-Bi-Ni alloy was internally oxidized in air. The phase constitution,surface morphology and microstructure evolution of the alloy after internal oxidation were analyzed by X-ray diffractometry,optical microscop...Ag-Sn-Cu-Bi-Ni alloy was internally oxidized in air. The phase constitution,surface morphology and microstructure evolution of the alloy after internal oxidation were analyzed by X-ray diffractometry,optical microscopy and scanning electron microscopy,respectively. The results show that the surface color of samples after internal oxidation is different from the different oxidation time and temperatures. The oxidation reaction firstly takes place on the grain boundaries. The microstructure developed on the initial stage of internal oxidation is fir-tree crystal texture. However,this texture structure disappears accompanied by grain growth and oxides forming during the prolonged oxidation. Finally,the oxide particles are uniformly dispersed in the silver matrix.展开更多
Five alloys Sn-5Bi-xAg (x = 0, 1, 2, 3, and 4 in at %) are produced by rapid solidification using melt-spinning technique. From temperature dependence of electrical resistivity (TDR), it is found that the Sn-5Bi-xAg (...Five alloys Sn-5Bi-xAg (x = 0, 1, 2, 3, and 4 in at %) are produced by rapid solidification using melt-spinning technique. From temperature dependence of electrical resistivity (TDR), it is found that the Sn-5Bi-xAg (x = 1, 2, 3, 4 in at %) rapidly solidified by melt spinning technique are narrow band semiconductor alloys. The energy gap Eg decreases by increasing Ag concentration from 203 meV for Sn-5Bi-1Ag to 97.5 meV for Sn-5Bi-4Ag alloy. From x-ray diffraction analysis (XRD), it is found that the Hume-Rothery condition for phase stability is not satisfied for this alloy.展开更多
基金supported by the National Natural Science Foundation of China (No.51901153)Shanxi Scholarship Council of China (No.2019032)+2 种基金Natural Science Foundation of Shanxi Province,China (No.202103021224049)the Shanxi Zhejiang University New Materials and Chemical Research Institute Scientific Research Project,China (No.2022SX-TD025)the Open Project of Salt Lake Chemical Engineering Research Complex,Qinghai University,China (No.2023-DXSSKF-Z02)。
文摘The influence of the slip mode on the microstructure evolution and compressive flow behavior at different strains in an extruded dilute Mg−0.5Bi−0.5Sn−0.5Mn alloy was analyzed through electron backscatter diffraction,X-ray diffraction,transmission electron microscopy,and hot compression tests.The results showed that at a low strain of 0.05,the basal,pyramidaland<c+a>slip modes were simultaneously activated.Nevertheless,at the middle stage of deformation(strain of 0.1,0.2 and 0.5),theslip mode was difficult to be activated and<c+a>slip mode became dominant.The deformation process between strains of 0.2 and 0.5 was primarily characterized by the softening effect resulting from the simultaneous occurrence of continuous dynamic recrystallization and discontinuous dynamic recrystallization.Ultimately,at strain of 0.8,a dynamic equilibrium was established,with the flow stress remaining constant due to the interplay between the dynamic softening brought about by discontinuous dynamic recrystallization and the work-hardening effect induced by the activation of the basalslip mode.
基金Projects(50571533, 50371024) supported by the National Natural Science Foundation of ChinaProject(104106) supported by Chinese Ministry of Euducation
文摘The effect of the liquid-liquid structure transition(L-LST) on the solidification behaviors and morphologies of Sn-Bi alloys was studied further. The results show that the undercooling of the primary and eutectic phase increases and the microstructure becomes finer after solidifying from the melt experiencing the L-LST. In the meantime, in hypoeutectic alloy, when solidifying from the melt experiencing the L-LST, the morphology of primary phase changes from the fir-tree crystal into the equiaxed crystal, and less primary phase and more eutectic structure are observed. Moreover, in eutectic alloy, the spacing of eutectic phase decreases markedly. These investigations would be beneficial to further exploration of the correlation between the melt structure and the micro mechanism of solidification.
基金supported by the National Natural Science Foundation of China (No. 50972010)the Fundamental Research Funds for the Central Universities (No. FRF-TP-09-021B)the Austrian Science Foundation (No. P20488-N19)
文摘The surface tension of a promising lead-free solder Au-Bi-Sn alloys was investigated both by the sessile-drop method and calculation. Experimental measurements were carried out for two cross-sections with the constant gold to bismuth ration of 1:1 and 1:2. For all the investigated compositions, decrease of the surface tension is observed with increasing temperature. Meanwhile, the surface tension values were also calculated based on Butler’s equation, with using the newest research on thermodynamics data of Au-Bi-Sn ternary system. Compared with the experimental results, a good agreement was obtained.
文摘The goal of the present work is to investigate the effects of the addition of Sb (0, 3 and 6 wt%) on structure, melting, corrosion and mechanical properties of Sn-Bi eutectic solder alloys. The mechanical properties of the bulk Sn-Bi-Sb solders were higher as the amount of antimony increases, making compressive strength augment from 65 MPa to 100 MPa when 6 wt% Sb was incorporated to the Sn-Bi eutectic alloy. The three alloys presented a melting temperature that is smaller to the one exhibited by the eutectic alloy Sn-38Pb (Tm = 183°C). According to the electrochemical results, the addition of higher contents of Sb to the Sn-Bi eutectic alloy had a positive effect: it ennobled the Ecorr values.
基金financially supported by the project of Yangtze Normal University under grant No.2017KYQD130 and No.2017XJQN08
文摘The stray crystals seriously affect the properties of metals which fabricated by directional solidification(DS). In order to observe the formation of the stray crystals, the growth behavior of Sn-10 wt.%Bi alloy was observed by synchrotron X-ray imaging technique using self-developed directional solidification(DS) apparatus. The experimental results show that Sn–10 wt.%Bi alloy is oriented with the form of dendrites to grow into the liquid phase during the DS process, and dendrites are arranged neatly to form columnar crystal microstructures. It is also found that parts of the dendrite arms begin to crack. These cracked dendrites drift upward to grow up in front of the solid-liquid interface and form stray crystals.
基金Project (2006BAE03B03) supported by the Key Project of 11th Five-Year Plan of China
文摘Ag-Sn-Cu-Bi-Ni alloy was internally oxidized in air. The phase constitution,surface morphology and microstructure evolution of the alloy after internal oxidation were analyzed by X-ray diffractometry,optical microscopy and scanning electron microscopy,respectively. The results show that the surface color of samples after internal oxidation is different from the different oxidation time and temperatures. The oxidation reaction firstly takes place on the grain boundaries. The microstructure developed on the initial stage of internal oxidation is fir-tree crystal texture. However,this texture structure disappears accompanied by grain growth and oxides forming during the prolonged oxidation. Finally,the oxide particles are uniformly dispersed in the silver matrix.
文摘Five alloys Sn-5Bi-xAg (x = 0, 1, 2, 3, and 4 in at %) are produced by rapid solidification using melt-spinning technique. From temperature dependence of electrical resistivity (TDR), it is found that the Sn-5Bi-xAg (x = 1, 2, 3, 4 in at %) rapidly solidified by melt spinning technique are narrow band semiconductor alloys. The energy gap Eg decreases by increasing Ag concentration from 203 meV for Sn-5Bi-1Ag to 97.5 meV for Sn-5Bi-4Ag alloy. From x-ray diffraction analysis (XRD), it is found that the Hume-Rothery condition for phase stability is not satisfied for this alloy.
