The evolution of the eutectic structures in the alloys with different copper contents during heat treatment was studied by scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), and differential...The evolution of the eutectic structures in the alloys with different copper contents during heat treatment was studied by scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), and differential scanning calorimetry(DSC). The as cast microstructures involve α(Al), eutectic(α(Al) + Mg(Al, Cu, Zn)2) and Al7Cu2Fe. The Al2CuMg particles form during heat treatment. The volume of coarse phases decreases quickly in the initial 12 h during heat treatment. The volume of coarse phases change a little at 400 and 420 ℃. Copper content has a great influence on the evolution of the eutectic. The coarse phases dissolve slowly in alloy with higher copper content.展开更多
The influence of coarse Cu-bearing particles, matrix and subgrain boundary precipitates on the stress corrosion susceptibility of the Al-Zn-Mg-Cu alloys was investigated. The strength of 7150 alloy is about 15 MPa hig...The influence of coarse Cu-bearing particles, matrix and subgrain boundary precipitates on the stress corrosion susceptibility of the Al-Zn-Mg-Cu alloys was investigated. The strength of 7150 alloy is about 15 MPa higher than that of 7010 alloy. The 7010 alloy exhibits higher resistance to stress corrosion cracking as compared with the 7150 alloy. The coarse Cu-bearing particles are detrimental to the resistance to stress corrosion cracking. The increase of size of matrix and subgrain boundary precipitates decreases the susceptibility of stress corrosion. The anodic dissolution and hydrogen embrittlement govern the cracking process. The severity of stress corrosion cracking is shown to be related to the coarse Cu-bearing particles, matrix and subgrain precipitates in Al-Zn-Mg-Cu alloys.展开更多
In this study, Cu was added into the high-pressure die-casting Al-5.5 Mg-0.7 Mn(wt%) alloy to improve the tensile properties. The effects of Cu addition on the microstructures, mechanical properties of the Al-5.5 Mg-0...In this study, Cu was added into the high-pressure die-casting Al-5.5 Mg-0.7 Mn(wt%) alloy to improve the tensile properties. The effects of Cu addition on the microstructures, mechanical properties of the Al-5.5 Mg-0.7 Mn alloys under both as-cast and T5 treatment conditions have been investigated. Additions of 0.5 wt%, 0.8 wt% and 1.5 wt% Cu can lead to the formation of irregular-shaped Al2 CuMg particles distributed along the grain boundaries in the as-cast alloys. Furthermore, the rest of Cu can dissolve into the matrixes. The lath-shaped Al2 CuMg precipitates with a size of 15–20 nm × 2–4 nm were generated in the T5-treated Al-5.5 Mg-0.7 Mn-x Cu(x = 0.5, 0.8, 1.5 wt%) alloys. The room temperature tensile and yield strengths of alloys increase with increasing the content of Cu. Increasing Cu content results in more Al2 CuMg phase formation along the grain boundaries, which causes more cracks during tensile deformation and lower ductility. Al-5.5 Mg-0.7 Mn-0.8 Cu alloy exhibits excellent comprehensive tensile properties under both as-cast and T5-treated conditions. The yield strength of 179 MPa, the ultimate tensile strength of 303 MPa and the elongation of 8.7% were achieved in the as-cast Al-5.5 Mg-0.7 Mn-0.8 Cu alloy, while the yield strength significantly was improved to 198 MPa after T5 treatment.展开更多
基金Project(2004AA5BG018) supported by the Science and Technology Development Fund of Harbin, China
文摘The evolution of the eutectic structures in the alloys with different copper contents during heat treatment was studied by scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), and differential scanning calorimetry(DSC). The as cast microstructures involve α(Al), eutectic(α(Al) + Mg(Al, Cu, Zn)2) and Al7Cu2Fe. The Al2CuMg particles form during heat treatment. The volume of coarse phases decreases quickly in the initial 12 h during heat treatment. The volume of coarse phases change a little at 400 and 420 ℃. Copper content has a great influence on the evolution of the eutectic. The coarse phases dissolve slowly in alloy with higher copper content.
基金Project(2004AA5BG018) supported by the Science and Technology Development Fund of Harbin, China
文摘The influence of coarse Cu-bearing particles, matrix and subgrain boundary precipitates on the stress corrosion susceptibility of the Al-Zn-Mg-Cu alloys was investigated. The strength of 7150 alloy is about 15 MPa higher than that of 7010 alloy. The 7010 alloy exhibits higher resistance to stress corrosion cracking as compared with the 7150 alloy. The coarse Cu-bearing particles are detrimental to the resistance to stress corrosion cracking. The increase of size of matrix and subgrain boundary precipitates decreases the susceptibility of stress corrosion. The anodic dissolution and hydrogen embrittlement govern the cracking process. The severity of stress corrosion cracking is shown to be related to the coarse Cu-bearing particles, matrix and subgrain precipitates in Al-Zn-Mg-Cu alloys.
基金supported financially by the National Key Research and Development Program of China (No. 2016YFB0301001)
文摘In this study, Cu was added into the high-pressure die-casting Al-5.5 Mg-0.7 Mn(wt%) alloy to improve the tensile properties. The effects of Cu addition on the microstructures, mechanical properties of the Al-5.5 Mg-0.7 Mn alloys under both as-cast and T5 treatment conditions have been investigated. Additions of 0.5 wt%, 0.8 wt% and 1.5 wt% Cu can lead to the formation of irregular-shaped Al2 CuMg particles distributed along the grain boundaries in the as-cast alloys. Furthermore, the rest of Cu can dissolve into the matrixes. The lath-shaped Al2 CuMg precipitates with a size of 15–20 nm × 2–4 nm were generated in the T5-treated Al-5.5 Mg-0.7 Mn-x Cu(x = 0.5, 0.8, 1.5 wt%) alloys. The room temperature tensile and yield strengths of alloys increase with increasing the content of Cu. Increasing Cu content results in more Al2 CuMg phase formation along the grain boundaries, which causes more cracks during tensile deformation and lower ductility. Al-5.5 Mg-0.7 Mn-0.8 Cu alloy exhibits excellent comprehensive tensile properties under both as-cast and T5-treated conditions. The yield strength of 179 MPa, the ultimate tensile strength of 303 MPa and the elongation of 8.7% were achieved in the as-cast Al-5.5 Mg-0.7 Mn-0.8 Cu alloy, while the yield strength significantly was improved to 198 MPa after T5 treatment.
