In this study,the Mg-3Zn-0.5Zr-χNd(χ=0,0.6)alloys were subjected to final rolling treatment with large deformation of 50%.The impact of annealing temperatures on the microstructure and mechanical properties was inve...In this study,the Mg-3Zn-0.5Zr-χNd(χ=0,0.6)alloys were subjected to final rolling treatment with large deformation of 50%.The impact of annealing temperatures on the microstructure and mechanical properties was investigated.The rolled Mg-3Zn-0.5Zr-0.6Nd alloy exhibited an ultimate tensile strength of 386 MPa,a yield strength of 361 MPa,and an elongation of 7.1%.Annealing at different temperatures resulted in reduced strength and obviously increased elongation for both alloys.Optimal mechanical properties for the Mg-3Zn-0.5Zr-0.6Nd alloy were achieved after annealing at 200℃,with an ultimate tensile strength of 287 MPa,a yield strength of 235 MPa,and an elongation of 26.1%.The numerous deformed microstructures,twins,and precipitated phases in the rolled alloy could impede the deformation at room temperature and increase the work hardening rate.After annealing,a decrease in the work hardening effect and an increase in the dynamic recovery effect were obtained due to the formation of fine equiaxed grains,and the increased volume fraction of precipitated phases,which significantly improved the elongation of the alloy.Additionally,the addition of Nd element could enhance the annealing recrystallization rate,reduce the Schmid factor difference between basal and prismatic slip systems,facilitate multi-system slip initiation and improve the alloy plasticity.展开更多
Studies on the mechanical properties and microstructures of as-cast and extruded Mg-Ce-Zn-Zr and Mg-Nd-Zn-Zr alloys have been made before and after heat treatment. The results show that the mechanical properties of as...Studies on the mechanical properties and microstructures of as-cast and extruded Mg-Ce-Zn-Zr and Mg-Nd-Zn-Zr alloys have been made before and after heat treatment. The results show that the mechanical properties of as-cast Mg-Ce and Mg-Nd alloys are as good as those of typical die cast AZ91 alloy and the heat resistant WE43 alloy. In Nd-containing alloys, the precipitated phase Mg_ 12Nd contributes significantly to age hardening. The mechanical properties of extruded alloys are improved obviously compared with those of as-cast alloys. The ultimate strength is 257.8MPa for extruded Mg-Ce alloy and 265.6MPa for extruded Mg-Nd alloy. Extrusion is a useful method to improve both the strengths and elongations of the two experimental alloys at both ambient and elevated temperatures. The grain refinement and precipitation strengthening are the main strengthening mechanisms in the alloys. Tensile fracture surfaces show a dimple pattern after extruding and therefore reflect an improved elongation.展开更多
Mg-3.4Nd-0.1Zn-0.40Zr alloy samples with and without containing gadolinium(0.6%,mass fraction) were prepared by sand casting.The aged hardening behavior,solidification microstructures and mechanical properties of the ...Mg-3.4Nd-0.1Zn-0.40Zr alloy samples with and without containing gadolinium(0.6%,mass fraction) were prepared by sand casting.The aged hardening behavior,solidification microstructures and mechanical properties of the alloys were investigated by using the analysis methods of OM,XRD,TEM,hardness tests and mechanical property tests.The main research results are as follows.1) Compared with the alloy without the addition of gadolinium,the alloys with the addition of gadolinium shows the more remarkable age-hardening response.2) The as-cast microstructure of the alloy with and without containing gadolinium consists ofα-Mg grains with Mg_(12)Nd phase on the grain boundary.After solution heat-treatment,Mg_(12)Nd phase of the alloy without containing gadolinium is dissolved in the matrix,however,there is still discontinued Mgl2Nd phase at grain boundary of the alloy with containing gadolinium.The more finely dispersed precipitates in Mg matrix are formed in the alloy with containing gadolinium during age-treatment.3) The room temperature and high temperature mechanical properties of the alloy are satisfactory,withσ_b=280 MPa,σ_(0.2)=165 MPa at RT andσ_b=215 MPa,σ_(0.2)=155 MPa at 250℃.The high temperature mechanical properties decrease slightly with the increase of temperature.展开更多
基金Project(202203021221088)supported by the Fundamental Research Program of Shanxi Province,ChinaProject(20230010)supported by the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province,China+5 种基金Project(202201050201012)supported by the Shanxi Provincial Science and Technology Major Special Project Plan of Taking the Lead in Unveiling the List,ChinaProject(2023-063)supported by the Research Project Supported by Shanxi Scholarship Council of ChinaProjects(51771129,52271109)supported by the National Natural Science Foundation of ChinaProject(2021YFB3703300)supported by the National Key Research and Development Program for Young Scientists,ChinaProject(YDZJSX2021B019)supported by the Special Fund Project for Guiding Local Science and Technology Development by the Central Government,ChinaProject(SKL-YSJ202103)supported by the Open Foundation of State Key Laboratory of High-end Compressor and System Technology,China。
文摘In this study,the Mg-3Zn-0.5Zr-χNd(χ=0,0.6)alloys were subjected to final rolling treatment with large deformation of 50%.The impact of annealing temperatures on the microstructure and mechanical properties was investigated.The rolled Mg-3Zn-0.5Zr-0.6Nd alloy exhibited an ultimate tensile strength of 386 MPa,a yield strength of 361 MPa,and an elongation of 7.1%.Annealing at different temperatures resulted in reduced strength and obviously increased elongation for both alloys.Optimal mechanical properties for the Mg-3Zn-0.5Zr-0.6Nd alloy were achieved after annealing at 200℃,with an ultimate tensile strength of 287 MPa,a yield strength of 235 MPa,and an elongation of 26.1%.The numerous deformed microstructures,twins,and precipitated phases in the rolled alloy could impede the deformation at room temperature and increase the work hardening rate.After annealing,a decrease in the work hardening effect and an increase in the dynamic recovery effect were obtained due to the formation of fine equiaxed grains,and the increased volume fraction of precipitated phases,which significantly improved the elongation of the alloy.Additionally,the addition of Nd element could enhance the annealing recrystallization rate,reduce the Schmid factor difference between basal and prismatic slip systems,facilitate multi-system slip initiation and improve the alloy plasticity.
文摘Studies on the mechanical properties and microstructures of as-cast and extruded Mg-Ce-Zn-Zr and Mg-Nd-Zn-Zr alloys have been made before and after heat treatment. The results show that the mechanical properties of as-cast Mg-Ce and Mg-Nd alloys are as good as those of typical die cast AZ91 alloy and the heat resistant WE43 alloy. In Nd-containing alloys, the precipitated phase Mg_ 12Nd contributes significantly to age hardening. The mechanical properties of extruded alloys are improved obviously compared with those of as-cast alloys. The ultimate strength is 257.8MPa for extruded Mg-Ce alloy and 265.6MPa for extruded Mg-Nd alloy. Extrusion is a useful method to improve both the strengths and elongations of the two experimental alloys at both ambient and elevated temperatures. The grain refinement and precipitation strengthening are the main strengthening mechanisms in the alloys. Tensile fracture surfaces show a dimple pattern after extruding and therefore reflect an improved elongation.
基金supported by National Natural Science Foundation of China(Nos.51975146,52205344)the Natural Science Foundation of Shandong Province,China(No.ZR2020QE171)+1 种基金the Key Research and Development Plan in Shandong Province,China(No.2019JZZY010364)the National Defense Basic Scientific Research of China(No.JCK2018603C017)。
基金Project(2006CB605202)supported by the National Basic Research Program of ChinaProject(CX200705)supported by the DoctorateFoundation of Northwestern Polytechnical University,China
文摘Mg-3.4Nd-0.1Zn-0.40Zr alloy samples with and without containing gadolinium(0.6%,mass fraction) were prepared by sand casting.The aged hardening behavior,solidification microstructures and mechanical properties of the alloys were investigated by using the analysis methods of OM,XRD,TEM,hardness tests and mechanical property tests.The main research results are as follows.1) Compared with the alloy without the addition of gadolinium,the alloys with the addition of gadolinium shows the more remarkable age-hardening response.2) The as-cast microstructure of the alloy with and without containing gadolinium consists ofα-Mg grains with Mg_(12)Nd phase on the grain boundary.After solution heat-treatment,Mg_(12)Nd phase of the alloy without containing gadolinium is dissolved in the matrix,however,there is still discontinued Mgl2Nd phase at grain boundary of the alloy with containing gadolinium.The more finely dispersed precipitates in Mg matrix are formed in the alloy with containing gadolinium during age-treatment.3) The room temperature and high temperature mechanical properties of the alloy are satisfactory,withσ_b=280 MPa,σ_(0.2)=165 MPa at RT andσ_b=215 MPa,σ_(0.2)=155 MPa at 250℃.The high temperature mechanical properties decrease slightly with the increase of temperature.
