The ultra high strength SiC particles （SiCp） reinforced Al-10%Zn-3.6%Mg-1.8%Cu-0.36%Zr-0.15% Ni composite was prepared by spray co-deposition. Microstructures of the extruded and different heat-treated bars were ana...The ultra high strength SiC particles （SiCp） reinforced Al-10%Zn-3.6%Mg-1.8%Cu-0.36%Zr-0.15% Ni composite was prepared by spray co-deposition. Microstructures of the extruded and different heat-treated bars were analyzed by transmission electron microscopy （TEM） and energy dispersive spectrometry （EDS）. Grain size of the composites prepared by two-stage solution is smaller than that by single-stage solution. After single-stage solution aging treatment, fine precipitates of both η and AlZnMgCu-rich phase can be found both intragranularly and intergranularly. While after the two-stage solution, an amorphous Si-Cu-Al-O （5 nm） layer appears at the interface. The addition of Ni and Zr modified the influence of the two-stage solution and inhibited the growth of the 7090/SiCp composite grain size. Heat treatments can significantly improve the fracture toughness of the composite. The fracture toughness first decreases then increases with the elongation of the aging time.展开更多
To improve the corrosion resistance, electrodeposition of Cu coating on Mg-3.0Nd-0.2Zn-0.4Zr （mass fraction, %NZ30K） magnesium alloy via an appropriate pretreatment was investigated. The surface morphologies, compos...To improve the corrosion resistance, electrodeposition of Cu coating on Mg-3.0Nd-0.2Zn-0.4Zr （mass fraction, %NZ30K） magnesium alloy via an appropriate pretreatment was investigated. The surface morphologies, compositions and microstructures of the pretreated films and Cu coating were characterized in detail. The results show that the activation film consists of fluoride and phosphates and Zn immersion film forms preferentially on the eutectic compound Mg12Nd phase region. A smooth, uniform and dense Cu coating is successfully obtained. Potentiodynamic polarization tests reveal that Cu coating can greatly improve the corrosion resistance of NZ30K magnesium alloy. Open circuit potential （OCP） and electrochemical impedance spectroscopy （EIS） tests during long-term immersion further demonstrate that Cu coating can provide an effective protection for NZ30K magnesium alloy from corrosion up to ~60 h, due to its dense structure and a stable passive film formed. In addition, Cu coating exhibits good adhesion to substrate as confirmed by thermal shock test.展开更多
基金Project (02Gky2004) supported by Hunan Provincial Science and Technology Department, China
文摘The ultra high strength SiC particles （SiCp） reinforced Al-10%Zn-3.6%Mg-1.8%Cu-0.36%Zr-0.15% Ni composite was prepared by spray co-deposition. Microstructures of the extruded and different heat-treated bars were analyzed by transmission electron microscopy （TEM） and energy dispersive spectrometry （EDS）. Grain size of the composites prepared by two-stage solution is smaller than that by single-stage solution. After single-stage solution aging treatment, fine precipitates of both η and AlZnMgCu-rich phase can be found both intragranularly and intergranularly. While after the two-stage solution, an amorphous Si-Cu-Al-O （5 nm） layer appears at the interface. The addition of Ni and Zr modified the influence of the two-stage solution and inhibited the growth of the 7090/SiCp composite grain size. Heat treatments can significantly improve the fracture toughness of the composite. The fracture toughness first decreases then increases with the elongation of the aging time.
基金Project(51371116)supported by the National Natural Science Foundation of ChinaProject supported by the Foundation of Open Research Topic in State Key Laboratory of Metal Matrix Composite,China
文摘To improve the corrosion resistance, electrodeposition of Cu coating on Mg-3.0Nd-0.2Zn-0.4Zr （mass fraction, %NZ30K） magnesium alloy via an appropriate pretreatment was investigated. The surface morphologies, compositions and microstructures of the pretreated films and Cu coating were characterized in detail. The results show that the activation film consists of fluoride and phosphates and Zn immersion film forms preferentially on the eutectic compound Mg12Nd phase region. A smooth, uniform and dense Cu coating is successfully obtained. Potentiodynamic polarization tests reveal that Cu coating can greatly improve the corrosion resistance of NZ30K magnesium alloy. Open circuit potential （OCP） and electrochemical impedance spectroscopy （EIS） tests during long-term immersion further demonstrate that Cu coating can provide an effective protection for NZ30K magnesium alloy from corrosion up to ~60 h, due to its dense structure and a stable passive film formed. In addition, Cu coating exhibits good adhesion to substrate as confirmed by thermal shock test.
