Li addition is verified to be an effective method to increase the room temperature ductility and formability of Mg alloys.In the present study,the microstructure,texture,and tensile properties of the extruded Mg-1Zn-x...Li addition is verified to be an effective method to increase the room temperature ductility and formability of Mg alloys.In the present study,the microstructure,texture,and tensile properties of the extruded Mg-1Zn-xLi(wt%,x=0,1,3,5)alloy sheets were studied by X-ray diffraction(XRD),scanning electron microscope(SEM),and electron backscatter diffraction(EBSD).It was found that Li addition resulted in the grain coarsening and the development of new transverse direction(TD)-tilting and{101^(-)0}parallel to extrusion direction textures,which was related to the improved dynamic recrystallization and the increased prismatic slip during extrusion.The Mg-1 Zn-5 Li sheet showed the weakest texture,which contained both basal and TD-tilting oriented grains.No additional phase was formed with Li addition.The yield strength of Mg-1Zn-xLi sheets gradually decreased with increasing Li content,which was mainly related to the grain coarsening and texture weakening.In addition,the ductility of the Mg-1Zn-xLi sheet was remarkably enhanced by Li addition.The elongation of the Mg-1 Zn-5 Li sheet was 30.3%along the TD,which was three times than that of Mg-1 Zn sheet.Microstructural analysis implied that this significant ductility enhancement was associated with the improvement activation of prismatic and basal slips during the tensile tests.This study may provide insights into the development of high-ductility,low-density Mg-Zn-Li based alloys.展开更多
The effects of Ce addition on the microstructure of Mg-6Zn-1Mn alloy during casting, homogenization, hot extrusion, T4, T6 and T4＋two-step aging were investigated. The mechanical properties of alloys with and without...The effects of Ce addition on the microstructure of Mg-6Zn-1Mn alloy during casting, homogenization, hot extrusion, T4, T6 and T4＋two-step aging were investigated. The mechanical properties of alloys with and without Ce were compared. The results showed that Ce had an obvious effect on the microstructure of ZM61-0.5Ce alloy by restricting the occurrence of dynamic recrystallization and restraining the grain growth during extrusion and heat treatment subsequently. A new binary phase Mg 12 Ce was identified in ZM61-0.5Ce alloy, which distributed at grain boundaries and was broken to small particles distributed at grain boundaries along extrusion direction during extrusion. The mechanical properties of as-extruded ZM61-0.5Ce alloy were improved with the addition of Ce. The improved tensile properties of as-extruded ZM61-0.5Ce alloy were due to the finer grain sizes as compared to ZM61 alloy. However, the UTS and YS decreased severely and the elongation increased when ZM61-0.5Ce was treated by T6 and T4＋two-step aging. Brittle Mg 12 Ce phase, which was distributed at the grain boundary areas and cannot dissolve into the Mg matrix after solution treatment, became crack source under tensile stress.展开更多
Mg-14Li-1Al （LA141）, LA141-0.3Y, LA141-0.3Sr, and LA141-0.3Y-0.3Sr alloys were prepared in an induction furnace in the argon atmosphere. The microstructures of these alloys were investigated through scanning electro...Mg-14Li-1Al （LA141）, LA141-0.3Y, LA141-0.3Sr, and LA141-0.3Y-0.3Sr alloys were prepared in an induction furnace in the argon atmosphere. The microstructures of these alloys were investigated through scanning electron microscope （SEM）, X-ray diffractometer （XRD） and energy dispersive spectrometer （EDS）. The results show that yttrium and/or strontium additions produce a strong grain refining effect in LA141 alloy. The mean grain sizes of the alloys with addition of Y and/or Sr are reduced remarkably from 600 to 500, 260, 230 μm, respectively. Al 2 Y, Al 4 Sr and Mg 17 Sr 2 phases with different morphologies are verified and exist inside the grain or at the grain boundaries, thus possibly act as heterogeneous nucleation sites and pin up grain boundaries, which restrain the grain growth.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. U1764253, U2037601, U1910213, 51971044, and 52001037)the Qinghai Science and Technology Program, China (No. 2018GX-A1)
文摘Li addition is verified to be an effective method to increase the room temperature ductility and formability of Mg alloys.In the present study,the microstructure,texture,and tensile properties of the extruded Mg-1Zn-xLi(wt%,x=0,1,3,5)alloy sheets were studied by X-ray diffraction(XRD),scanning electron microscope(SEM),and electron backscatter diffraction(EBSD).It was found that Li addition resulted in the grain coarsening and the development of new transverse direction(TD)-tilting and{101^(-)0}parallel to extrusion direction textures,which was related to the improved dynamic recrystallization and the increased prismatic slip during extrusion.The Mg-1 Zn-5 Li sheet showed the weakest texture,which contained both basal and TD-tilting oriented grains.No additional phase was formed with Li addition.The yield strength of Mg-1Zn-xLi sheets gradually decreased with increasing Li content,which was mainly related to the grain coarsening and texture weakening.In addition,the ductility of the Mg-1Zn-xLi sheet was remarkably enhanced by Li addition.The elongation of the Mg-1 Zn-5 Li sheet was 30.3%along the TD,which was three times than that of Mg-1 Zn sheet.Microstructural analysis implied that this significant ductility enhancement was associated with the improvement activation of prismatic and basal slips during the tensile tests.This study may provide insights into the development of high-ductility,low-density Mg-Zn-Li based alloys.
基金Project(2007CB613700)supported by the National Basic Research Program of ChinaProject(2007BAG06B04)supported by the National Key Technology R&D Program+2 种基金Project(CSTC,2009AB4008)supported by the Chongqing Sci&Tech ProgramProject(50725413)supported by the National Natural Science Foundation of ChinaProject(CDJXS10132202)supported by the Fundamental Research Funds for the Central Universities, China
文摘The effects of Ce addition on the microstructure of Mg-6Zn-1Mn alloy during casting, homogenization, hot extrusion, T4, T6 and T4＋two-step aging were investigated. The mechanical properties of alloys with and without Ce were compared. The results showed that Ce had an obvious effect on the microstructure of ZM61-0.5Ce alloy by restricting the occurrence of dynamic recrystallization and restraining the grain growth during extrusion and heat treatment subsequently. A new binary phase Mg 12 Ce was identified in ZM61-0.5Ce alloy, which distributed at grain boundaries and was broken to small particles distributed at grain boundaries along extrusion direction during extrusion. The mechanical properties of as-extruded ZM61-0.5Ce alloy were improved with the addition of Ce. The improved tensile properties of as-extruded ZM61-0.5Ce alloy were due to the finer grain sizes as compared to ZM61 alloy. However, the UTS and YS decreased severely and the elongation increased when ZM61-0.5Ce was treated by T6 and T4＋two-step aging. Brittle Mg 12 Ce phase, which was distributed at the grain boundary areas and cannot dissolve into the Mg matrix after solution treatment, became crack source under tensile stress.
基金Project(50725413)supported by the National Natural Science Foundation of ChinaProject(2010CSTC-BJLKR)supported by Chongqing Science and Technology Commission, ChinaProject(CDJXS10132203)supported by the Fundamental Research Funds for the Central Universities,China
文摘Mg-14Li-1Al （LA141）, LA141-0.3Y, LA141-0.3Sr, and LA141-0.3Y-0.3Sr alloys were prepared in an induction furnace in the argon atmosphere. The microstructures of these alloys were investigated through scanning electron microscope （SEM）, X-ray diffractometer （XRD） and energy dispersive spectrometer （EDS）. The results show that yttrium and/or strontium additions produce a strong grain refining effect in LA141 alloy. The mean grain sizes of the alloys with addition of Y and/or Sr are reduced remarkably from 600 to 500, 260, 230 μm, respectively. Al 2 Y, Al 4 Sr and Mg 17 Sr 2 phases with different morphologies are verified and exist inside the grain or at the grain boundaries, thus possibly act as heterogeneous nucleation sites and pin up grain boundaries, which restrain the grain growth.
