The microstructure and mechanical properties of cast Mg-9Al-2Sn-xMn(x=0,0.1,0.3 wt.%)alloys in as-cast,solution treated and aged conditions are investigated.The results reveal that Mn addition into Mg-9Al-2Sn alloy le...The microstructure and mechanical properties of cast Mg-9Al-2Sn-xMn(x=0,0.1,0.3 wt.%)alloys in as-cast,solution treated and aged conditions are investigated.The results reveal that Mn addition into Mg-9Al-2Sn alloy leads to the formation of Al8(Mn,Fe)5 phases,the grain refinement and the increase of discontinuous Mg17Al12 precipitates along the grain boundaries.0.1 wt.%Mn addition has an obvious effect on accelerating the aging behavior of Mg-9Al-2Sn alloy at the early aging period up to 8 h,while 0.3 wt.%Mn addition alloy has an comparable aging behavior with the Mn-free alloy.Mn addition has less influence on the fracture behavior of Mg-9Al-2Sn alloy,while the fracture pattern is mainly determined by the thermal conditions.Mg-9Al-2Sn-0.1Mn alloy has the best combination of strength and elongation when aged at 200℃ for 8 h and the yield strength,ultimate tensile strength and elongation are 154 MPa,292MPa and 5%,respectively.展开更多
In order to have a better understanding of the hot deformation behavior of the as-solution-treated Mg-4 Zn-2 Sn-2 Al（ZAT422） alloy, a series of compression experiments with a height reduction of 60% were performed i...In order to have a better understanding of the hot deformation behavior of the as-solution-treated Mg-4 Zn-2 Sn-2 Al（ZAT422） alloy, a series of compression experiments with a height reduction of 60% were performed in the temperature range of 498-648 K and the strain rate range of 0.01-5 s～（-1） on a Gleeble 3800 thermo-mechanical simulator. Based on the regression analysis by Arrhenius type equation and Avrami type equation of flow behavior, the activation energy of deformation of ZAT422 alloy was determined as 155.652 k J/mol, and the constitutive equations for flow behavior and the dynamic recrystallization（DRX） kinetic model of ZAT422 alloy were established. Microstructure observation shows that when the temperature is as low as 498 K, the DRX is not completed as the true strain reaches 0.9163. However, with the temperature increasing to 648 K, the lower strain rate is more likely to result in some grains＇ abnormal growth.展开更多
To understand the solidification pathway and microstructure evolution of Mg-9Al-2Ca alloy,the cooling curve of the alloy solidified under furnace cooling was measured and the water-quenched samples were observed.The e...To understand the solidification pathway and microstructure evolution of Mg-9Al-2Ca alloy,the cooling curve of the alloy solidified under furnace cooling was measured and the water-quenched samples were observed.The experimental results show that the matrix phase of α-Mg dendrites is first generated at 596℃ during the solidification process,then the eutectic phases of Al_(2)Ca and Mg_(17)Al_(12) are formed at 518 and 447℃,respectively,and the solidification is terminated at 436℃.In the process of solidification,the seaweed dendrites of α-Mg get coarser and are gradually transformed into the global dendrites;besides,the secondary dendrite arms spacing(SDAS)of α-Mg as well as the solid fraction are both increased,while the increasing rate of SDAS of α-Mg and the solid fraction in the temperature region of 600-550℃ is faster than that in the temperature region of 550-436℃.And a power function relationship can be used to illustrate the change of the SDAS and the solid fraction with the temperature of solidification.展开更多
基金This research work is collaborated by General Motors Global Research and Development(GM R&D),Warren,MI,USA,and Shanghai Jiao Tong University(SJTU),Shanghai,China.Dr P.Fu would like to acknowledge the support of a Specialized Research Fund for the Doctoral Program of Higher Education(20110073120008)a project from Shanghai Science and Technology Committee(12DZ0501700).
文摘The microstructure and mechanical properties of cast Mg-9Al-2Sn-xMn(x=0,0.1,0.3 wt.%)alloys in as-cast,solution treated and aged conditions are investigated.The results reveal that Mn addition into Mg-9Al-2Sn alloy leads to the formation of Al8(Mn,Fe)5 phases,the grain refinement and the increase of discontinuous Mg17Al12 precipitates along the grain boundaries.0.1 wt.%Mn addition has an obvious effect on accelerating the aging behavior of Mg-9Al-2Sn alloy at the early aging period up to 8 h,while 0.3 wt.%Mn addition alloy has an comparable aging behavior with the Mn-free alloy.Mn addition has less influence on the fracture behavior of Mg-9Al-2Sn alloy,while the fracture pattern is mainly determined by the thermal conditions.Mg-9Al-2Sn-0.1Mn alloy has the best combination of strength and elongation when aged at 200℃ for 8 h and the yield strength,ultimate tensile strength and elongation are 154 MPa,292MPa and 5%,respectively.
基金Project(2016YFB0301105)supported by the National Key Research and Development Plan,ChinaProject(ZR2015YL007)supported by the Natural Science Foundation of Shandong Province,ChinaProject(ZR2015EQ019)supported by the Natural Science Foundation of Shandong Province,China
文摘In order to have a better understanding of the hot deformation behavior of the as-solution-treated Mg-4 Zn-2 Sn-2 Al（ZAT422） alloy, a series of compression experiments with a height reduction of 60% were performed in the temperature range of 498-648 K and the strain rate range of 0.01-5 s～（-1） on a Gleeble 3800 thermo-mechanical simulator. Based on the regression analysis by Arrhenius type equation and Avrami type equation of flow behavior, the activation energy of deformation of ZAT422 alloy was determined as 155.652 k J/mol, and the constitutive equations for flow behavior and the dynamic recrystallization（DRX） kinetic model of ZAT422 alloy were established. Microstructure observation shows that when the temperature is as low as 498 K, the DRX is not completed as the true strain reaches 0.9163. However, with the temperature increasing to 648 K, the lower strain rate is more likely to result in some grains＇ abnormal growth.
基金Funded by the Ph D Research Startup Foundation of Jining University(No.2017BSZX02)。
文摘To understand the solidification pathway and microstructure evolution of Mg-9Al-2Ca alloy,the cooling curve of the alloy solidified under furnace cooling was measured and the water-quenched samples were observed.The experimental results show that the matrix phase of α-Mg dendrites is first generated at 596℃ during the solidification process,then the eutectic phases of Al_(2)Ca and Mg_(17)Al_(12) are formed at 518 and 447℃,respectively,and the solidification is terminated at 436℃.In the process of solidification,the seaweed dendrites of α-Mg get coarser and are gradually transformed into the global dendrites;besides,the secondary dendrite arms spacing(SDAS)of α-Mg as well as the solid fraction are both increased,while the increasing rate of SDAS of α-Mg and the solid fraction in the temperature region of 600-550℃ is faster than that in the temperature region of 550-436℃.And a power function relationship can be used to illustrate the change of the SDAS and the solid fraction with the temperature of solidification.
