Ultrasonic vibration was introduced into the Mg-8Li-3A1 alloy melt during its solidification process. The microstructure, corrosion resistance and mechanical properties of the Mg-8Li-3A1 alloy under ultrasonic vibrati...Ultrasonic vibration was introduced into the Mg-8Li-3A1 alloy melt during its solidification process. The microstructure, corrosion resistance and mechanical properties of the Mg-8Li-3A1 alloy under ultrasonic vibration were investigated. The experiment results show that the morphology of a phase is modified from coarse rosette-like structure to fine globular one with the application of ultrasonic vibration. The fine globular structure is obtained especially when the power is 170 W, and the refining effect also gets better with prolonging the ultrasonic treatment time. The corrosion resistance of the alloy with 170 W of ultrasonic vibration for 90 s is improved apparently compared with the alloy without ultrasonic vibration. The mechanical properties of alloys with ultrasonic vibration are also both improved apparently. The tensile strength and elongation of alloy improve by 9.5% and 45.7%, respectively, with 170 W of ultrasonic treatment for 90 s.展开更多
The billets of Al-Zn-Mg-Cu-Zr and Al-Zn-Mg-Cu-Zr-0.5Er alloys were prepared by semi-continuous direct chill casting （DCC）.The effects of trace Er on microstructure of Al-Zn-Mg-Cu-Zr alloy under as-cast and homogeniz...The billets of Al-Zn-Mg-Cu-Zr and Al-Zn-Mg-Cu-Zr-0.5Er alloys were prepared by semi-continuous direct chill casting （DCC）.The effects of trace Er on microstructure of Al-Zn-Mg-Cu-Zr alloy under as-cast and homogenization conditions were studied.The results show that the grain morphology is large dendritic structure and the grain size increases obviously by the addition of 0.5% Er.Moreover,most of Er element in the alloy segregates at grain boundary during solidification,resulting in ternary Al8Cu4Er phase.After homogenization,most of the MgZn2 phase at grain boundary has dissolved back to Al matrix in the two alloys.In the Er-containing alloy,the dissolution temperature of Al8Cu4Er phase is about 575 °C.Therefore,the homogenization treatment cannot eliminate Al8Cu4Er phase validity.展开更多
The microstructure and mechanical properties of AZ80 magnesium alloys with varying Nd, Gd contents were investigated. The results revealed that the as-cast microstructure of AZ80 alloy was composed of α-Mg matrix and...The microstructure and mechanical properties of AZ80 magnesium alloys with varying Nd, Gd contents were investigated. The results revealed that the as-cast microstructure of AZ80 alloy was composed of α-Mg matrix and divorced eutectic β-Mg_（17）Al_（12） phases. The fraction of Mg_（17）Al_（12） phase was reduced when 0.6 wt.% Nd was added, and new rod-shaped Al_（11）Nd_3 phase and small block-shaped Al-Nd-Mn phase appeared. With Gd addition, the Gd elements mixed with Nd to form rare earth phases. New block-shaped Al_2Gd and Al_2Nd phases which were collectively called Al_2RE phases were observed in the microstructure with more than 0.6 wt.% Gd addition. Moreover, the addition of Gd could promote the precipitation of block-shaped Al_2RE phase, and inhibit the original rod-shaped Al_（11）Nd_3 phase. The AZ80-0.6Nd-0.6Gd alloy exhibited the optimal mechanical properties among all the experimental alloys, in which the tensile strength, yield strength and elongation were 215, 145 MPa and 8.33%, respectively.展开更多
基金Project(2009AA03Z525)supported by the High-tech Research and Development Program of ChinaProject(NCET-08-0080)supported by the Program of New Century Excellent Talents of the Ministry of Education of China+1 种基金Project(20082172)supported by the Natural Science Fund of Liaoning Province,ChinaProject(2009J21DW003)supported by the Science and Technology Fund of Dalian City,China
文摘Ultrasonic vibration was introduced into the Mg-8Li-3A1 alloy melt during its solidification process. The microstructure, corrosion resistance and mechanical properties of the Mg-8Li-3A1 alloy under ultrasonic vibration were investigated. The experiment results show that the morphology of a phase is modified from coarse rosette-like structure to fine globular one with the application of ultrasonic vibration. The fine globular structure is obtained especially when the power is 170 W, and the refining effect also gets better with prolonging the ultrasonic treatment time. The corrosion resistance of the alloy with 170 W of ultrasonic vibration for 90 s is improved apparently compared with the alloy without ultrasonic vibration. The mechanical properties of alloys with ultrasonic vibration are also both improved apparently. The tensile strength and elongation of alloy improve by 9.5% and 45.7%, respectively, with 170 W of ultrasonic treatment for 90 s.
基金Project(50875031) supported by the National Natural Science Foundation of ChinaProject(2005CB623705) supported by National Basic Research Program of China
文摘The billets of Al-Zn-Mg-Cu-Zr and Al-Zn-Mg-Cu-Zr-0.5Er alloys were prepared by semi-continuous direct chill casting （DCC）.The effects of trace Er on microstructure of Al-Zn-Mg-Cu-Zr alloy under as-cast and homogenization conditions were studied.The results show that the grain morphology is large dendritic structure and the grain size increases obviously by the addition of 0.5% Er.Moreover,most of Er element in the alloy segregates at grain boundary during solidification,resulting in ternary Al8Cu4Er phase.After homogenization,most of the MgZn2 phase at grain boundary has dissolved back to Al matrix in the two alloys.In the Er-containing alloy,the dissolution temperature of Al8Cu4Er phase is about 575 °C.Therefore,the homogenization treatment cannot eliminate Al8Cu4Er phase validity.
基金Project supported by the National Natural Science Foundation of China(51375071,51374047)Foundation of Liaoning Educational Committee of China(L2013031)Fundamental Research Funds for the Central University(DUT15ZD201,DUT14RC(3)134)
文摘The microstructure and mechanical properties of AZ80 magnesium alloys with varying Nd, Gd contents were investigated. The results revealed that the as-cast microstructure of AZ80 alloy was composed of α-Mg matrix and divorced eutectic β-Mg_（17）Al_（12） phases. The fraction of Mg_（17）Al_（12） phase was reduced when 0.6 wt.% Nd was added, and new rod-shaped Al_（11）Nd_3 phase and small block-shaped Al-Nd-Mn phase appeared. With Gd addition, the Gd elements mixed with Nd to form rare earth phases. New block-shaped Al_2Gd and Al_2Nd phases which were collectively called Al_2RE phases were observed in the microstructure with more than 0.6 wt.% Gd addition. Moreover, the addition of Gd could promote the precipitation of block-shaped Al_2RE phase, and inhibit the original rod-shaped Al_（11）Nd_3 phase. The AZ80-0.6Nd-0.6Gd alloy exhibited the optimal mechanical properties among all the experimental alloys, in which the tensile strength, yield strength and elongation were 215, 145 MPa and 8.33%, respectively.
基金National High Technology Research and Development Program of China (2009AA03Z525)National Natural Science Foundation of China (50875031)+1 种基金Aviation Science Foundation of China (20095263005)Youth Foundation of Dalian University of Technology (2006)
