The microstructures of different treated Al-5Mg-0.5Sc-0. 1Zr alloys have been studied with opticalmicroscopy and transmission electron microscope (TEM). Coherent particles with the matrix were found inas-cast sample. ...The microstructures of different treated Al-5Mg-0.5Sc-0. 1Zr alloys have been studied with opticalmicroscopy and transmission electron microscope (TEM). Coherent particles with the matrix were found inas-cast sample. composite Al3Sc/Al3Zr particles were found after 13 h homogenized treatment under 470℃.Coherent precipitates pinned dislocations and low-angle grain boundaries. and then restrained recrystallization. All kinds of particles of different treatments were not larger than 40nm. After high-temperaturestabilization treatments, most particles remain coherent with the matrix. The reasons of microstructurechange at different treated conditions have been analyzed.展开更多
In order to overcome the trade-off between the strength and electrical conductivity of aluminum alloy conductors,the new Al-Ce-Sc,Al-Ce-Y,Al-Ce-Zr and Al-Ce-Sc-Y alloys were prepared by die casting,high temperature ho...In order to overcome the trade-off between the strength and electrical conductivity of aluminum alloy conductors,the new Al-Ce-Sc,Al-Ce-Y,Al-Ce-Zr and Al-Ce-Sc-Y alloys were prepared by die casting,high temperature homogenization treatment,hot extrusion and cold drawing.Adding Sc and Y eliminated the dendrite segregation of the as-cast Al-0.2 Ce alloy and promoted the formation of equiaxed grains with the average grain size of 142.5μm.The Al-0.2 Ce-0.2 Sc-0.1 Y alloy inherited the great tensile properties of Al-0.2 Ce-0.2 Sc alloy and the high electrical conductivity of Al-0.2 Ce-0.1 Y alloy simultaneously.After cold drawing and annealing at 200℃for 5 h,the ultimate tensile strength of Al-0.2 Ce-0.2 Sc-0.1 Y alloy reached 200 MPa and 198 MPa,the elongation reached 6.8%and 8.5%,and the electrical conductivity reached 61.01%and 61.77%,respectively.The main second phase of Al-0.2 Ce-0.2 Sc-0.1 Y alloy after hot extrusion were Al_(13)Fe_3 Ce containing a few Y and Si atoms.The larger size and proportion of the second phase greatly reduced the concentration of solute Fe and Si atoms and the addition of Y significantly decreased the density of defects after cold drawing compared to Al-0.2 Ce-0.2 Sc alloy,which improved electrical conductivity of the alloy.Furthermore,the dispersed and coherent nano-size Al_3 Sc precipitions of Al-0.2 Ce-0.2 Sc-0.1 Y alloy greatly improved strength,elongation and heat resistance.Compared with Al-0.2 Ce-0.2 Sc alloy,the lower density of dislocation,stacking fault and subgrain boundary and the larger size of Al_3 Sc precipitions with enrichment of Y atoms enable the Al-0.2 Ce-0.2 Sc-0.1 Y alloy to maintain high strength,elongation and electrical conductivity after annealing.展开更多
文摘The microstructures of different treated Al-5Mg-0.5Sc-0. 1Zr alloys have been studied with opticalmicroscopy and transmission electron microscope (TEM). Coherent particles with the matrix were found inas-cast sample. composite Al3Sc/Al3Zr particles were found after 13 h homogenized treatment under 470℃.Coherent precipitates pinned dislocations and low-angle grain boundaries. and then restrained recrystallization. All kinds of particles of different treatments were not larger than 40nm. After high-temperaturestabilization treatments, most particles remain coherent with the matrix. The reasons of microstructurechange at different treated conditions have been analyzed.
基金supported financially by the Key Research and Development Program of Guangdong Province(NO.2020B010186002)the Science and Technology Major Project of Hunan Province(NO.2017GK4002)。
文摘In order to overcome the trade-off between the strength and electrical conductivity of aluminum alloy conductors,the new Al-Ce-Sc,Al-Ce-Y,Al-Ce-Zr and Al-Ce-Sc-Y alloys were prepared by die casting,high temperature homogenization treatment,hot extrusion and cold drawing.Adding Sc and Y eliminated the dendrite segregation of the as-cast Al-0.2 Ce alloy and promoted the formation of equiaxed grains with the average grain size of 142.5μm.The Al-0.2 Ce-0.2 Sc-0.1 Y alloy inherited the great tensile properties of Al-0.2 Ce-0.2 Sc alloy and the high electrical conductivity of Al-0.2 Ce-0.1 Y alloy simultaneously.After cold drawing and annealing at 200℃for 5 h,the ultimate tensile strength of Al-0.2 Ce-0.2 Sc-0.1 Y alloy reached 200 MPa and 198 MPa,the elongation reached 6.8%and 8.5%,and the electrical conductivity reached 61.01%and 61.77%,respectively.The main second phase of Al-0.2 Ce-0.2 Sc-0.1 Y alloy after hot extrusion were Al_(13)Fe_3 Ce containing a few Y and Si atoms.The larger size and proportion of the second phase greatly reduced the concentration of solute Fe and Si atoms and the addition of Y significantly decreased the density of defects after cold drawing compared to Al-0.2 Ce-0.2 Sc alloy,which improved electrical conductivity of the alloy.Furthermore,the dispersed and coherent nano-size Al_3 Sc precipitions of Al-0.2 Ce-0.2 Sc-0.1 Y alloy greatly improved strength,elongation and heat resistance.Compared with Al-0.2 Ce-0.2 Sc alloy,the lower density of dislocation,stacking fault and subgrain boundary and the larger size of Al_3 Sc precipitions with enrichment of Y atoms enable the Al-0.2 Ce-0.2 Sc-0.1 Y alloy to maintain high strength,elongation and electrical conductivity after annealing.
