The as-cast microstructure,tensile and creep properties of Mg-3Sn-1Ca and Mg-3Sn-2Ca magnesium alloys were investigated and compared by using optical microscopy and scanning electron microscopy,X-ray diffraction analy...The as-cast microstructure,tensile and creep properties of Mg-3Sn-1Ca and Mg-3Sn-2Ca magnesium alloys were investigated and compared by using optical microscopy and scanning electron microscopy,X-ray diffraction analysis and tensile tests. The results indicate that the as-cast microstructures of Mg-3Sn-1Ca and Mg-3Sn-2Ca alloys are different.The former is mainly composed ofα-Mg,eutectic CaMgSn and solid state precipitation of Mg 2 Sn,whereas the latter is mainly composed ofα-Mg, primary CaMgSn,eutectic CaMgSn and Mg2Ca phases.As a result,the two alloys obtain different tensile and creep properties. Mg-3Sn-1Ca alloy shows relatively higher ultimate tensile strength and elongation at room temperature and 150℃than Mg-3Sn-2Ca alloy,however,the yield strengths of Mg-3Sn-1Ca alloy at room temperature and 150℃are relatively low.In addition,the creep properties of Mg-3Sn-1Ca alloy at 150℃and 70 MPa for 100 h are obviously lower than those of the Mg-3Sn-2Ca alloy.展开更多
Minor Sr was introduced to the Mg-3Sn-2Ca （wt.%） alloy in this paper, and the effects of minor Sr addition on the as-cast microstructure and mechanical properties of the Mg-3Sn-2Ca （wt.%） alloy were investigated b...Minor Sr was introduced to the Mg-3Sn-2Ca （wt.%） alloy in this paper, and the effects of minor Sr addition on the as-cast microstructure and mechanical properties of the Mg-3Sn-2Ca （wt.%） alloy were investigated by using of optical and electron microscopies, differential scanning calorimetry （DSC） analysis, and tensile and creep tests. The results indicate that, after adding 0.034wt.%, 0.065wt.% or 0.10wt.% Sr to the Mg- 3Sn-2Ca alloy, the morphology of the primary CaMgSn phase changes from the initial coarse needle-like net to relatively fine short block and/or particle-like shapes. At the same time, the additions of 0.034wt.% or 0.065wt.% Sr suppress the formation of the primary CaMgSn phase, and the addition of 0.10wt.% Sr not only suppresses the formation of the primary and eutectic CaMgSn phases but also promotes the formation of Mg2Ca phase. Furthermore, the addition of minor Sr to the Mg-3Sn-2Ca alloy can improve the tensile properties of the alloy both at room temperature and 150 ℃. The creep property of the Mg-3Sn-2Ca alloy at 150 ~C is also improved by the additions of 0.034wt.% and 0.065wt.% Sr; however, the addition of 0.10wt.% Sr is not beneficial to the creep properties of the Mg-3Sn-2Ca alloy.展开更多
The effects of little Ce addition on the as-cast microstructure and creep properties of Mg-3Sn-2Ca magnesium alloy were investigated.The results indicate that adding 0.5%(mass fraction)Ce to Mg-3Sn-2Ca alloy does not ...The effects of little Ce addition on the as-cast microstructure and creep properties of Mg-3Sn-2Ca magnesium alloy were investigated.The results indicate that adding 0.5%(mass fraction)Ce to Mg-3Sn-2Ca alloy does not cause the formation of any new phase in the alloy.However,an interesting microstructural change in the as-cast Mg-3Sn-2Ca alloy added with 0.5%Ce is observed. After adding 0.5%Ce to Mg-3Sn-2Ca alloy,not only the volume fraction of CaMgSn phase in the alloy is decreased but also the CaMgSn phases in the alloy are refined.In addition,adding 0.5%Ce to Mg-3Sn-2Ca alloy can also improve the creep-resistant properties of the alloy.After adding 0.5%Ce to Mg-3Sn-2Ca alloy,the second creep rate of the alloy at 150℃and 70 MPa for 100 h changes from 3.28×10-8to 1.81×10 -8s -1.展开更多
基金Project(50725413)supported by the National Natural Science Foundation of ChinaProject(2007CB613704)supported by the National Basic Research Program of ChinaProjects(2007BB4400and KJ090628)supported by the Chongqing Science and Technology Commission and Education Commission of China
文摘The as-cast microstructure,tensile and creep properties of Mg-3Sn-1Ca and Mg-3Sn-2Ca magnesium alloys were investigated and compared by using optical microscopy and scanning electron microscopy,X-ray diffraction analysis and tensile tests. The results indicate that the as-cast microstructures of Mg-3Sn-1Ca and Mg-3Sn-2Ca alloys are different.The former is mainly composed ofα-Mg,eutectic CaMgSn and solid state precipitation of Mg 2 Sn,whereas the latter is mainly composed ofα-Mg, primary CaMgSn,eutectic CaMgSn and Mg2Ca phases.As a result,the two alloys obtain different tensile and creep properties. Mg-3Sn-1Ca alloy shows relatively higher ultimate tensile strength and elongation at room temperature and 150℃than Mg-3Sn-2Ca alloy,however,the yield strengths of Mg-3Sn-1Ca alloy at room temperature and 150℃are relatively low.In addition,the creep properties of Mg-3Sn-1Ca alloy at 150℃and 70 MPa for 100 h are obviously lower than those of the Mg-3Sn-2Ca alloy.
基金supported by the Chongqing Science and Technology Commission in China(Nos.2011ggB50013,2011jjA50019 and 2011AC4119)the Chongqing Education Commission of China(No.KJ120834)the Open Funds from the Key Laboratory of Manufacture and Test Techniques for Automobile Parts(Chongqing University of Technology),Ministry of Education in 2012
文摘Minor Sr was introduced to the Mg-3Sn-2Ca （wt.%） alloy in this paper, and the effects of minor Sr addition on the as-cast microstructure and mechanical properties of the Mg-3Sn-2Ca （wt.%） alloy were investigated by using of optical and electron microscopies, differential scanning calorimetry （DSC） analysis, and tensile and creep tests. The results indicate that, after adding 0.034wt.%, 0.065wt.% or 0.10wt.% Sr to the Mg- 3Sn-2Ca alloy, the morphology of the primary CaMgSn phase changes from the initial coarse needle-like net to relatively fine short block and/or particle-like shapes. At the same time, the additions of 0.034wt.% or 0.065wt.% Sr suppress the formation of the primary CaMgSn phase, and the addition of 0.10wt.% Sr not only suppresses the formation of the primary and eutectic CaMgSn phases but also promotes the formation of Mg2Ca phase. Furthermore, the addition of minor Sr to the Mg-3Sn-2Ca alloy can improve the tensile properties of the alloy both at room temperature and 150 ℃. The creep property of the Mg-3Sn-2Ca alloy at 150 ~C is also improved by the additions of 0.034wt.% and 0.065wt.% Sr; however, the addition of 0.10wt.% Sr is not beneficial to the creep properties of the Mg-3Sn-2Ca alloy.
基金Project(50725413)supported by the National Natural Science Foundation for Distinguished Young Scholar in ChinaProject(2007CB613704)supported by the National Basic Research Program of ChinaProjects(2006AA4012-9-6 and 2007BB4400)supported by the Chongqing Science and Technology Commission of China
文摘The effects of little Ce addition on the as-cast microstructure and creep properties of Mg-3Sn-2Ca magnesium alloy were investigated.The results indicate that adding 0.5%(mass fraction)Ce to Mg-3Sn-2Ca alloy does not cause the formation of any new phase in the alloy.However,an interesting microstructural change in the as-cast Mg-3Sn-2Ca alloy added with 0.5%Ce is observed. After adding 0.5%Ce to Mg-3Sn-2Ca alloy,not only the volume fraction of CaMgSn phase in the alloy is decreased but also the CaMgSn phases in the alloy are refined.In addition,adding 0.5%Ce to Mg-3Sn-2Ca alloy can also improve the creep-resistant properties of the alloy.After adding 0.5%Ce to Mg-3Sn-2Ca alloy,the second creep rate of the alloy at 150℃and 70 MPa for 100 h changes from 3.28×10-8to 1.81×10 -8s -1.
