A series of Al-8.2Zn-2.1Mg-2.3Cu based as-cast alloys and some plates with thickness of 4 mm containing minor Sc and Zr were prepared. The effect of joint addition of minor Sc and Zr on microstructure and mechanical p...A series of Al-8.2Zn-2.1Mg-2.3Cu based as-cast alloys and some plates with thickness of 4 mm containing minor Sc and Zr were prepared. The effect of joint addition of minor Sc and Zr on microstructure and mechanical properties of Al-Zn-Mg-Cu alloys were investigated by using OM, SEM with EDS and TEM. The results show that by adding 0.18% Zr (mass fraction) in the cast alloy, the grains can be refined to a certain degree, and by adding 0.18% Sc a little as well. Adding Sc and Zr can generate strong grain refinement effect and obtain a fine equiaxed grain structure, because primary Al3(ScxZr1- )precipitation forms in front of the x a-Al grains. The microstructure and tensile test results show that 0.18% addition of Zr does not bring higher tensile strength and elongation to the alloy of adding Sc, but a better inhibition to recrystallization. Recrystallization inhibiting effect is the strongest in the alloys with joint addition of Sc and Zr. When the content of Zr is unchanged, the strength and elongation of the alloys increase with increasing Sc addition. The increase of strength and elongation in the alloys is related to the refine grain strengthening, precipitation particles strengthening and substructure strengthening principles.展开更多
The hot deformation behaviors and microstructures of A1-Zn-Mg-Cu-Cr aluminum alloy have been studied using thermal simulation test, optical microscopy and transmission electron microscopy. As a result, the true stress...The hot deformation behaviors and microstructures of A1-Zn-Mg-Cu-Cr aluminum alloy have been studied using thermal simulation test, optical microscopy and transmission electron microscopy. As a result, the true stress versus true strain curves and the microstructures under various deformation conditions are obtained. The microstructures gradually incline to dynamic-recrystallization with the deformation temperature rising and the recrystallization grains refine with the decrease of deformation temperature or with raising the strain rates. The quantitative relationship between the Zener-Hollomon parameter （Z） and average recrystallization grain size in the subsequent heat treatment is set up.展开更多
对净化前、后合金氢含量和力学性能进行测试,并采用TEM对等离子净化后的Al-Zn-Mg合金时效组织进行分析。结果表明:Al-Zn-Mg合金氢含量由0.17 mL/100 g Al降低到0.11 mL/100 g Al;经460℃×120 min固溶、130℃×16 h时效处理后,...对净化前、后合金氢含量和力学性能进行测试,并采用TEM对等离子净化后的Al-Zn-Mg合金时效组织进行分析。结果表明:Al-Zn-Mg合金氢含量由0.17 mL/100 g Al降低到0.11 mL/100 g Al;经460℃×120 min固溶、130℃×16 h时效处理后,晶内的析出相细小弥散,晶界上析出相连续分布,GP区起主要的强化作用;Rm达到590 MPa,Rp0.2达到510 MPa,断后伸长率达到8.5%,硬度达到160HB。展开更多
基金Project(2005CB623706) supported by the National Advanced Technology Research and Development Committee of China
文摘A series of Al-8.2Zn-2.1Mg-2.3Cu based as-cast alloys and some plates with thickness of 4 mm containing minor Sc and Zr were prepared. The effect of joint addition of minor Sc and Zr on microstructure and mechanical properties of Al-Zn-Mg-Cu alloys were investigated by using OM, SEM with EDS and TEM. The results show that by adding 0.18% Zr (mass fraction) in the cast alloy, the grains can be refined to a certain degree, and by adding 0.18% Sc a little as well. Adding Sc and Zr can generate strong grain refinement effect and obtain a fine equiaxed grain structure, because primary Al3(ScxZr1- )precipitation forms in front of the x a-Al grains. The microstructure and tensile test results show that 0.18% addition of Zr does not bring higher tensile strength and elongation to the alloy of adding Sc, but a better inhibition to recrystallization. Recrystallization inhibiting effect is the strongest in the alloys with joint addition of Sc and Zr. When the content of Zr is unchanged, the strength and elongation of the alloys increase with increasing Sc addition. The increase of strength and elongation in the alloys is related to the refine grain strengthening, precipitation particles strengthening and substructure strengthening principles.
文摘The hot deformation behaviors and microstructures of A1-Zn-Mg-Cu-Cr aluminum alloy have been studied using thermal simulation test, optical microscopy and transmission electron microscopy. As a result, the true stress versus true strain curves and the microstructures under various deformation conditions are obtained. The microstructures gradually incline to dynamic-recrystallization with the deformation temperature rising and the recrystallization grains refine with the decrease of deformation temperature or with raising the strain rates. The quantitative relationship between the Zener-Hollomon parameter （Z） and average recrystallization grain size in the subsequent heat treatment is set up.
