A comprehensive study on the microstructural evolution of a new type Al-Zn-Mg-Cu-Er-Zr alloy duringhomogenization was conducted by optical microscope,scanning electron microscope,transmission electron microscopy and X...A comprehensive study on the microstructural evolution of a new type Al-Zn-Mg-Cu-Er-Zr alloy duringhomogenization was conducted by optical microscope,scanning electron microscope,transmission electron microscopy and X-raydiffraction analysis.The results show that serious segregation exists in as-cast alloy,and the primary phases are T(AlZnMgCu),S(Al2CuMg)and Al8Cu4Er,which preferentially locate in the grain boundary regions.The soluble T(AlZnMgCu)and S(Al2CuMg)phases dissolve into the matrix gradually during single-stage homogenized at465°C with prolonging holding time,but the residualAl8Cu4Er phase cannot dissolve completely.Compared with the single-stage homogenization,both a finer particle size and a highervolume fraction of L12-structured Al3(Er,Zr)dispersoids can be obtained in the two-stage homogenization process.A suitablehomogenization scheme for the present alloy is(400°C,10h)+(465°C,24h),which is consistent with the results of homogenizationkinetic analysis.展开更多
The effect of quenching rate on the aging precipitation behavior and properties of Al-Zn-Mg-Cu-Zr-Er alloy was investigated.The scanning electron microscopy,transmission electron microscopy,and atom probe tomography w...The effect of quenching rate on the aging precipitation behavior and properties of Al-Zn-Mg-Cu-Zr-Er alloy was investigated.The scanning electron microscopy,transmission electron microscopy,and atom probe tomography were used to study the characteristics of clusters and precipitates in the alloy.The quench-inducedηphase and a large number of clusters are formed in the air-cooled alloy with the slowest cooling rate,which contributes to an increment of hardness by 24%(HV 26)compared with that of the water-quenched one.However,the aging hardening response speed and peak-aged hardness of the alloy increase with the increase of quenching rate.Meanwhile,the water-quenched alloy after peak aging also has the highest strength,elongation,and corrosion resistance,which is due to the high driving force and increased number density of aging precipitates,and the narrowed precipitate free zones.展开更多
The solidification microstructure and mechanical properties of hypoeutectic Al-10Mg_(2)Si cast alloys with different Cu contents and 0.45 wt.% Er were investigated using an optical microscope, scanning electron micros...The solidification microstructure and mechanical properties of hypoeutectic Al-10Mg_(2)Si cast alloys with different Cu contents and 0.45 wt.% Er were investigated using an optical microscope, scanning electron microscope, and an electronic universal testing machine. Results showed that Cu and Er could significantly reduce the grain size of the eutectic Mg;Si phase from 15.4 μm for the base alloy to 5.8 μm for the alloy with 1.5 wt.% Cu and 0.45 wt.% Er.Meanwhile, the needle-like β-Al5Fe Si phase was modified to fine sized irregular shaped Cu, Er and Fe-rich particles with the additions of Cu and Er. The strength and ductility of the Al-10Mg_(2)Si as-cast alloys were simultaneously improved by the additions of Cu and Er, and the ultimate tensile strength, yield strength and elongation increase from 223 MPa,136 MPa and 2.1% to 337 MPa, 169 MPa and 4.7%, respectively. The heterogeneous nucleation of Mg_(2)Si on Al P was avoided by forming Cu, Er and P-containing phases, due to the additions of Cu and Er. Moreover, the Cu and Er atomic clusters and their intermetallic segregated on the surface of the eutectic Mg_(2)Si and inhibited the growth of the eutectic Mg_(2)Si, which were responsible for the modification of the eutectic Mg_(2)Si.展开更多
基金Project(2012CB619503) supported by the National Basic Research Program of ChinaProject(51201003) supported by the National Natural Science Foundation of ChinaProject(2142007) supported by Natural Science Foundation of Beijing,China
文摘A comprehensive study on the microstructural evolution of a new type Al-Zn-Mg-Cu-Er-Zr alloy duringhomogenization was conducted by optical microscope,scanning electron microscope,transmission electron microscopy and X-raydiffraction analysis.The results show that serious segregation exists in as-cast alloy,and the primary phases are T(AlZnMgCu),S(Al2CuMg)and Al8Cu4Er,which preferentially locate in the grain boundary regions.The soluble T(AlZnMgCu)and S(Al2CuMg)phases dissolve into the matrix gradually during single-stage homogenized at465°C with prolonging holding time,but the residualAl8Cu4Er phase cannot dissolve completely.Compared with the single-stage homogenization,both a finer particle size and a highervolume fraction of L12-structured Al3(Er,Zr)dispersoids can be obtained in the two-stage homogenization process.A suitablehomogenization scheme for the present alloy is(400°C,10h)+(465°C,24h),which is consistent with the results of homogenizationkinetic analysis.
基金the financial supports from the National Natural Science Foundation of China(No.51871033)the Opening Project of State Key Laboratory for Advanced Metals and Materials,China(No.2020-ZD02)。
文摘The effect of quenching rate on the aging precipitation behavior and properties of Al-Zn-Mg-Cu-Zr-Er alloy was investigated.The scanning electron microscopy,transmission electron microscopy,and atom probe tomography were used to study the characteristics of clusters and precipitates in the alloy.The quench-inducedηphase and a large number of clusters are formed in the air-cooled alloy with the slowest cooling rate,which contributes to an increment of hardness by 24%(HV 26)compared with that of the water-quenched one.However,the aging hardening response speed and peak-aged hardness of the alloy increase with the increase of quenching rate.Meanwhile,the water-quenched alloy after peak aging also has the highest strength,elongation,and corrosion resistance,which is due to the high driving force and increased number density of aging precipitates,and the narrowed precipitate free zones.
基金Project(51971106) supported by the National Natural Science Foundation of ChinaProject(GJJ191094) supported by the Education Department of Jiangxi Province,China+2 种基金Project(PA2019GDZC0096) supported by Fundamental Research Funds for the Central Universities of ChinaProject(2019-MS-171) supported by the Liaoning Natural Science Foundation,ChinaProject supported by Programs for Liaoning Innovative Talents/Groups and Liaoning Distinguished Professors,China。
文摘The solidification microstructure and mechanical properties of hypoeutectic Al-10Mg_(2)Si cast alloys with different Cu contents and 0.45 wt.% Er were investigated using an optical microscope, scanning electron microscope, and an electronic universal testing machine. Results showed that Cu and Er could significantly reduce the grain size of the eutectic Mg;Si phase from 15.4 μm for the base alloy to 5.8 μm for the alloy with 1.5 wt.% Cu and 0.45 wt.% Er.Meanwhile, the needle-like β-Al5Fe Si phase was modified to fine sized irregular shaped Cu, Er and Fe-rich particles with the additions of Cu and Er. The strength and ductility of the Al-10Mg_(2)Si as-cast alloys were simultaneously improved by the additions of Cu and Er, and the ultimate tensile strength, yield strength and elongation increase from 223 MPa,136 MPa and 2.1% to 337 MPa, 169 MPa and 4.7%, respectively. The heterogeneous nucleation of Mg_(2)Si on Al P was avoided by forming Cu, Er and P-containing phases, due to the additions of Cu and Er. Moreover, the Cu and Er atomic clusters and their intermetallic segregated on the surface of the eutectic Mg_(2)Si and inhibited the growth of the eutectic Mg_(2)Si, which were responsible for the modification of the eutectic Mg_(2)Si.
