A new Mg−10%Al−1%Zn−1%Si alloy with non-dendritic microstructure was prepared by strain induced melt activation(SIMA)process.The effect of compression ratio on the evolution of semisolid microstructure of the experime...A new Mg−10%Al−1%Zn−1%Si alloy with non-dendritic microstructure was prepared by strain induced melt activation(SIMA)process.The effect of compression ratio on the evolution of semisolid microstructure of the experimental alloy was investigated.The results indicate that the average size ofα-Mg grains decreases and spheroidizing tendency becomes more obvious with the compression ratios increasing from 0 to 40%.In addition,the eutectic Mg2Si phase in the Mg−10%Al−1%Zn−1%Si alloy transforms completely from the initial fishbone shape to globular shape by SIMA process.With the increasing of compression ratio,the morphology and average size of Mg2Si phases do not change obviously.The morphology modification mechanism of Mg2Si phase in Mg−10%Al−1%Zn−1%Si alloy by SIMA process was also studied.展开更多
In order to improve the activity and eliminate some impurities, pretreatment was used before hydrothermal synthesis. The fly ash was mixed with an aqueous NaOH solution, the alkali melted fly ash was also adopted, whi...In order to improve the activity and eliminate some impurities, pretreatment was used before hydrothermal synthesis. The fly ash was mixed with an aqueous NaOH solution, the alkali melted fly ash was also adopted, which is hydrothermally treated at about 104 ℃, and the liquid/solid ratio was controlled at 6：1. In order to control Si/Al molar ratio, SiO2 or Al2O3 powers were added to the fly ash. The results of XRD and SEM show that the alkali melted can activate fly ash and eliminate its quartz and mullite, along with the improvement of Si/Al molar ratio and alkalinity. In addition, zeolite Na-A changes into sodalite gradually, and nepheline is the synthesized intermediate product. Those results were discussed on the basis of a formation mechanism of zeolite from fly ash.展开更多
The effect of the Mg/Si ratio of Al-2.5Li-1Cu-0.8Mg-0.8Si,Al-2.5Li-1Cu-1.6Mg-0.8Si,and Al-2.5Li-1Cu-2.4Mg-0.8Si alloys on the microstructure evolution and mechanical properties was investigated.The results show that t...The effect of the Mg/Si ratio of Al-2.5Li-1Cu-0.8Mg-0.8Si,Al-2.5Li-1Cu-1.6Mg-0.8Si,and Al-2.5Li-1Cu-2.4Mg-0.8Si alloys on the microstructure evolution and mechanical properties was investigated.The results show that the primary phases and their morphologies in the as-cast alloys are found to vary with the Mg/Si ratio.The improvement of Mg/Si ratio of as-cast alloys promotes the formation of Mg_(2)Si primary phase at the expense of the AlLiSi primary phase.Moreover,a tiny amount of T_(B)-Al_(7.5)Cu_(4)Li phase transforms into S-Al_(2)CuMg phase with the increase of Mg content.In addition,the increase of Mg/Si ratio also causes the Cu-rich intergranular phase distributed along crystal boundary to Si-rich intergranular phase.After ageing treatment,the precipitation sequence as a function of Mg/Si ratio is as follows:δ/δ'+AlLiSi(Mg/Si is~1)→δ/δ'+β'-Mg_(2)Si+AlLiSi(Mg/Si is~2)→δ/δ'+β'-Mg_(2)Si(Mg/Si is~3).A good combination of strength and ductility can be obtained in Al-2.5Li-1Cu-2.4Mg-0.8Si alloy after solution and ageing.The rod-likeβ'-Mg_(2)Si precipitate has a positive influence on the comprehensive mechanical properties of the alloy.展开更多
The influence of different Si contents on the microstructure evolution and mechanical properties of Al⁃Mg⁃Si⁃Cu⁃Zn alloys was systematically studied using tensile testing,OM,SEM,EDS,and EBSD.The results indicate that ...The influence of different Si contents on the microstructure evolution and mechanical properties of Al⁃Mg⁃Si⁃Cu⁃Zn alloys was systematically studied using tensile testing,OM,SEM,EDS,and EBSD.The results indicate that the grain size of as⁃cast alloys was gradually reduced with the increase of the Si content,which mainly resulted from the formation of many iron⁃rich phases and precipitates during the casting process.During homogenization treatment,the plate⁃likeβ⁃AlFeSi phases in the alloy with a higher Si content easily transformed to the sphericalα⁃Al(FeMn)Si phases,which is helpful for improving the formability of alloys.The microstructure evolution of the alloys was also greatly dependent on the content of Si that the number density and homogeneous distribution level of precipitates in the final cold rolled alloys both increased with the increase of the Si content,which further provided a positive effect on the formation of fine recrystallization grains during the subsequent solution treatment.As a result,the yield strength,ultimate tensile strength,and elongation of the pre⁃aged alloys in the direction of 45°with respect to the rolling direction were all increased with increasing Si content.展开更多
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(Nos.41807235,50674038).
文摘A new Mg−10%Al−1%Zn−1%Si alloy with non-dendritic microstructure was prepared by strain induced melt activation(SIMA)process.The effect of compression ratio on the evolution of semisolid microstructure of the experimental alloy was investigated.The results indicate that the average size ofα-Mg grains decreases and spheroidizing tendency becomes more obvious with the compression ratios increasing from 0 to 40%.In addition,the eutectic Mg2Si phase in the Mg−10%Al−1%Zn−1%Si alloy transforms completely from the initial fishbone shape to globular shape by SIMA process.With the increasing of compression ratio,the morphology and average size of Mg2Si phases do not change obviously.The morphology modification mechanism of Mg2Si phase in Mg−10%Al−1%Zn−1%Si alloy by SIMA process was also studied.
基金Supported by the Henan Outstanding Youth Science Fund (0612002400)
文摘In order to improve the activity and eliminate some impurities, pretreatment was used before hydrothermal synthesis. The fly ash was mixed with an aqueous NaOH solution, the alkali melted fly ash was also adopted, which is hydrothermally treated at about 104 ℃, and the liquid/solid ratio was controlled at 6：1. In order to control Si/Al molar ratio, SiO2 or Al2O3 powers were added to the fly ash. The results of XRD and SEM show that the alkali melted can activate fly ash and eliminate its quartz and mullite, along with the improvement of Si/Al molar ratio and alkalinity. In addition, zeolite Na-A changes into sodalite gradually, and nepheline is the synthesized intermediate product. Those results were discussed on the basis of a formation mechanism of zeolite from fly ash.
基金financially supported by the National Natural Science Foundation of China(51774105)Touyan Innovation Team Program(XNAUEA5640208420)。
文摘The effect of the Mg/Si ratio of Al-2.5Li-1Cu-0.8Mg-0.8Si,Al-2.5Li-1Cu-1.6Mg-0.8Si,and Al-2.5Li-1Cu-2.4Mg-0.8Si alloys on the microstructure evolution and mechanical properties was investigated.The results show that the primary phases and their morphologies in the as-cast alloys are found to vary with the Mg/Si ratio.The improvement of Mg/Si ratio of as-cast alloys promotes the formation of Mg_(2)Si primary phase at the expense of the AlLiSi primary phase.Moreover,a tiny amount of T_(B)-Al_(7.5)Cu_(4)Li phase transforms into S-Al_(2)CuMg phase with the increase of Mg content.In addition,the increase of Mg/Si ratio also causes the Cu-rich intergranular phase distributed along crystal boundary to Si-rich intergranular phase.After ageing treatment,the precipitation sequence as a function of Mg/Si ratio is as follows:δ/δ'+AlLiSi(Mg/Si is~1)→δ/δ'+β'-Mg_(2)Si+AlLiSi(Mg/Si is~2)→δ/δ'+β'-Mg_(2)Si(Mg/Si is~3).A good combination of strength and ductility can be obtained in Al-2.5Li-1Cu-2.4Mg-0.8Si alloy after solution and ageing.The rod-likeβ'-Mg_(2)Si precipitate has a positive influence on the comprehensive mechanical properties of the alloy.
基金Supported by the National Key Research and Development Program of China(Grant No.2016YFB0300801)the National Natural Science Foundation of China(Grant Nos.51871029,51571023 and 51301016)+1 种基金the Beijing Natural Science Foundation(Grant No.2172038)the Government Guided Program Intergovernmental Bilateral Innovation Cooperation Project(Grant No.BZ2019019)
文摘The influence of different Si contents on the microstructure evolution and mechanical properties of Al⁃Mg⁃Si⁃Cu⁃Zn alloys was systematically studied using tensile testing,OM,SEM,EDS,and EBSD.The results indicate that the grain size of as⁃cast alloys was gradually reduced with the increase of the Si content,which mainly resulted from the formation of many iron⁃rich phases and precipitates during the casting process.During homogenization treatment,the plate⁃likeβ⁃AlFeSi phases in the alloy with a higher Si content easily transformed to the sphericalα⁃Al(FeMn)Si phases,which is helpful for improving the formability of alloys.The microstructure evolution of the alloys was also greatly dependent on the content of Si that the number density and homogeneous distribution level of precipitates in the final cold rolled alloys both increased with the increase of the Si content,which further provided a positive effect on the formation of fine recrystallization grains during the subsequent solution treatment.As a result,the yield strength,ultimate tensile strength,and elongation of the pre⁃aged alloys in the direction of 45°with respect to the rolling direction were all increased with increasing Si content.
