The effects of rare earth samarium （Sm） additions on the microstructure and mechanical properties of as-cast Al-Si-Cu alloy were investigated by optical microscopy and scanning electron microscopy （SEM）. The resul...The effects of rare earth samarium （Sm） additions on the microstructure and mechanical properties of as-cast Al-Si-Cu alloy were investigated by optical microscopy and scanning electron microscopy （SEM）. The results show that Sm can effectively refine the a（Al） dendrite and the eutectic silicon. In addition, the shape of iron-rich phases changes from the Chinese script-like to slender-like ones and the volume fraction of iron-rich phases is decreased by the addition of Sm. Two kinds of Sm-rich interrnetallics are found： AlSiSm and AlSiCuSm. The plate-like AlSiCuSm phase always associates with the needle-like AISiSm phase. The mechanical properties are improved by the addition of Sm, and the good ultimate tensile strength （220 MPa） and elongation （3. 1%） are obtained from the Al-Si-Cu-1.0Sin alloy.展开更多
The microstructure and mechanical properties of AZ61 magnesium alloy with Ca, Sm addition were investigated. The results showed that the addition of 0.5 wt.% Ca reduced the quantity of Mg17Al12 phase, and formed a new...The microstructure and mechanical properties of AZ61 magnesium alloy with Ca, Sm addition were investigated. The results showed that the addition of 0.5 wt.% Ca reduced the quantity of Mg17Al12 phase, and formed a new Al4 Ca phase which is reticular in AZ61 alloy. With the addition of Ca and Sm, the microstructure was further refined and new Al-Sm rich phases were formed in AZ61 alloy with 0.6 wt.%-1.5 wt.% Sm addition, the TEM analysis confirmed that they were Al2 Sm and Al4 Sm. Tensile tests showed that 1.0 wt.% Sm addition contributed to the formation of the Al2 Sm and Al4 Sm and the improvement in the ambient strength, i.e., an ultimate tensile strength of 327 MPa and an elongation of 10.1%. However, excessive Sm addition led to the coarsening of Al2 Sm and Al4 Sm phases, thus resulted in the decline of strength and plasticity.展开更多
The effect of Sm（0 wt.%-2 wt.%） addition on the corrosion behavior of Mg-6Al-1.2Y-0.9Nd alloy in 3.5 wt.% NaCl solution has been studied by static corrosion tests,corrosion morphology observation,corrosion scale and...The effect of Sm（0 wt.%-2 wt.%） addition on the corrosion behavior of Mg-6Al-1.2Y-0.9Nd alloy in 3.5 wt.% NaCl solution has been studied by static corrosion tests,corrosion morphology observation,corrosion scale and microstructure analysis.The results show that,with the increasing of Sm content,the corrosion rate of the alloy decreases at first,then increases and reaches the valley at 0.5 wt.% Sm.The reason is that the proper content of Sm addition can refine the precipitates and make the component and microstructure uniform,and therefore,it remarkably improves the corrosion resistance of the alloy.展开更多
Effects of samarium (Sm) content (0, 2.0, 3.5, 5.0, 6.5 wt%) on microstructure and mechanical proper-ties of Mg-0.5Zn-0.5 Zr alloy under as-cast and as-extruded states were thoroughly investigated. Results indicate th...Effects of samarium (Sm) content (0, 2.0, 3.5, 5.0, 6.5 wt%) on microstructure and mechanical proper-ties of Mg-0.5Zn-0.5 Zr alloy under as-cast and as-extruded states were thoroughly investigated. Results indicate that grains of the as-cast alloys are gradually refined as Sm content increases. The dominant intermetallic ph^se changes from Mg3Sm to Mg4iSm5 till Sm content exceeds 5.0 wt%. The dynami-cally precipitated intermetallic phase during hot-extrusion in dll Sm-containing alloys is Mg3Sm. The intermetallic particles induced by Sm addition could act as heterogeneous nucleation sites for dynamic recrystallization during hot extrusion. They promoted dynamic recrystallization via the particle stim-ulated nucleation mechanism, and resulted in weakening the basal texture in the as-extruded alloys. Sm addition can significantly enhance the strength of the as-extruded Mg-0.5Zn-0.5Zr alloy at room temperature, with the optimal dosage of 3.5 wt%. The optimal yield strength (YS) and ultimate tensile strength (UTS) are 368 MPa and 383 MPa, which were enhanced by approximately 23.1% and 20.8% com-pared with the Sm-free alloy, respectively. Based on microstructural analysis, the dominant strengthening mechanisms are revealed to be grain boundary strengthening and dispersion strengthening.展开更多
A Box-Behnken design （BBD） of response surface methodology （RSM） was used to optimize the preparation of the Zn-Sm antibacterial white carbon black by the sol-gel method. The statistical analysis of the results sh...A Box-Behnken design （BBD） of response surface methodology （RSM） was used to optimize the preparation of the Zn-Sm antibacterial white carbon black by the sol-gel method. The statistical analysis of the results showed that the particle size of the Zn-Sm antibacterial white carbon black was significantly affected by the reaction time, reaction temperature and the stirring speed. According to analysis of variance （ANOVA）, the values of the determination coefficient （R2=0.9821） and the ＂Pred R-Squared＂ of 0.8227 were in reasonable agreement with the ＂Adj R-Squared＂ of 0.9591. It was indicated that this model could be used to navigate the design space. The optimized reaction time, temperature and the stirring speed were 0.88 h, 87.83 ℃, and 473.45 r/rain, respectively. In addition, the bacteriostasis rate of the product was about 97.92%.展开更多
The effect of single addition of La or Sm on the microstructures and mechanical properties of an Al-Cu-Mn alloy were investigated by microstructure characterization and tensile test.The results show that addition of L...The effect of single addition of La or Sm on the microstructures and mechanical properties of an Al-Cu-Mn alloy were investigated by microstructure characterization and tensile test.The results show that addition of La or Sm into the Al-Cu-Mn alloy can remarkably increase the density of θ' phase and refine the microstructure,and thus,improves the mechanical properties at room temperature.La addition results in a more considerable increase in the density and refinement of θ' phase than Sm addition.La addition has a more significant contribution on the mechanical properties of the Al-Cu-Mn alloy than Sm addition.In addition,a new phase of Al_6Cu_6La is formed in the Al-Cu-Mn alloy with La addition.展开更多
基金Project(51165032)supported by the National Natural Science Foundation of ChinaProject(20122BAB216017)supported by the Natural Science Foundation of Jiangxi Province,ChinaProject(2011-TW-03)supported by the Open Foundation of Jiangxi Key Laboratory for Advanced Copper and Tungsten Materials,China
文摘The effects of rare earth samarium （Sm） additions on the microstructure and mechanical properties of as-cast Al-Si-Cu alloy were investigated by optical microscopy and scanning electron microscopy （SEM）. The results show that Sm can effectively refine the a（Al） dendrite and the eutectic silicon. In addition, the shape of iron-rich phases changes from the Chinese script-like to slender-like ones and the volume fraction of iron-rich phases is decreased by the addition of Sm. Two kinds of Sm-rich interrnetallics are found： AlSiSm and AlSiCuSm. The plate-like AlSiCuSm phase always associates with the needle-like AISiSm phase. The mechanical properties are improved by the addition of Sm, and the good ultimate tensile strength （220 MPa） and elongation （3. 1%） are obtained from the Al-Si-Cu-1.0Sin alloy.
基金supported by International Science and Technological Cooperating Project of the Ministry of Science and Technology of the PRC(2008DFR50040-08)
文摘The microstructure and mechanical properties of AZ61 magnesium alloy with Ca, Sm addition were investigated. The results showed that the addition of 0.5 wt.% Ca reduced the quantity of Mg17Al12 phase, and formed a new Al4 Ca phase which is reticular in AZ61 alloy. With the addition of Ca and Sm, the microstructure was further refined and new Al-Sm rich phases were formed in AZ61 alloy with 0.6 wt.%-1.5 wt.% Sm addition, the TEM analysis confirmed that they were Al2 Sm and Al4 Sm. Tensile tests showed that 1.0 wt.% Sm addition contributed to the formation of the Al2 Sm and Al4 Sm and the improvement in the ambient strength, i.e., an ultimate tensile strength of 327 MPa and an elongation of 10.1%. However, excessive Sm addition led to the coarsening of Al2 Sm and Al4 Sm phases, thus resulted in the decline of strength and plasticity.
文摘The effect of Sm（0 wt.%-2 wt.%） addition on the corrosion behavior of Mg-6Al-1.2Y-0.9Nd alloy in 3.5 wt.% NaCl solution has been studied by static corrosion tests,corrosion morphology observation,corrosion scale and microstructure analysis.The results show that,with the increasing of Sm content,the corrosion rate of the alloy decreases at first,then increases and reaches the valley at 0.5 wt.% Sm.The reason is that the proper content of Sm addition can refine the precipitates and make the component and microstructure uniform,and therefore,it remarkably improves the corrosion resistance of the alloy.
基金supported financially by the National Natural Science Foundation of China (Nos. 51701200 and 21601017)the Project for Science & Technology Development of Jilin Province (Nos. 2016YHZ0006, 20170414001GH, 20180520004JH and 20180520160JH)
文摘Effects of samarium (Sm) content (0, 2.0, 3.5, 5.0, 6.5 wt%) on microstructure and mechanical proper-ties of Mg-0.5Zn-0.5 Zr alloy under as-cast and as-extruded states were thoroughly investigated. Results indicate that grains of the as-cast alloys are gradually refined as Sm content increases. The dominant intermetallic ph^se changes from Mg3Sm to Mg4iSm5 till Sm content exceeds 5.0 wt%. The dynami-cally precipitated intermetallic phase during hot-extrusion in dll Sm-containing alloys is Mg3Sm. The intermetallic particles induced by Sm addition could act as heterogeneous nucleation sites for dynamic recrystallization during hot extrusion. They promoted dynamic recrystallization via the particle stim-ulated nucleation mechanism, and resulted in weakening the basal texture in the as-extruded alloys. Sm addition can significantly enhance the strength of the as-extruded Mg-0.5Zn-0.5Zr alloy at room temperature, with the optimal dosage of 3.5 wt%. The optimal yield strength (YS) and ultimate tensile strength (UTS) are 368 MPa and 383 MPa, which were enhanced by approximately 23.1% and 20.8% com-pared with the Sm-free alloy, respectively. Based on microstructural analysis, the dominant strengthening mechanisms are revealed to be grain boundary strengthening and dispersion strengthening.
基金Project supported by Yunnan Provincial Department of Education(2012Z102)
文摘A Box-Behnken design （BBD） of response surface methodology （RSM） was used to optimize the preparation of the Zn-Sm antibacterial white carbon black by the sol-gel method. The statistical analysis of the results showed that the particle size of the Zn-Sm antibacterial white carbon black was significantly affected by the reaction time, reaction temperature and the stirring speed. According to analysis of variance （ANOVA）, the values of the determination coefficient （R2=0.9821） and the ＂Pred R-Squared＂ of 0.8227 were in reasonable agreement with the ＂Adj R-Squared＂ of 0.9591. It was indicated that this model could be used to navigate the design space. The optimized reaction time, temperature and the stirring speed were 0.88 h, 87.83 ℃, and 473.45 r/rain, respectively. In addition, the bacteriostasis rate of the product was about 97.92%.
基金supported by the Research Fund of the State Key Laboratory of Solidification Processing (No. 42-QP-009)Fundamental Research Fund of Northwestern Polytechnical University (No. JC200929)the 111 Project of China (No. B08040)
文摘The effect of single addition of La or Sm on the microstructures and mechanical properties of an Al-Cu-Mn alloy were investigated by microstructure characterization and tensile test.The results show that addition of La or Sm into the Al-Cu-Mn alloy can remarkably increase the density of θ' phase and refine the microstructure,and thus,improves the mechanical properties at room temperature.La addition results in a more considerable increase in the density and refinement of θ' phase than Sm addition.La addition has a more significant contribution on the mechanical properties of the Al-Cu-Mn alloy than Sm addition.In addition,a new phase of Al_6Cu_6La is formed in the Al-Cu-Mn alloy with La addition.
