This research studied the mechanism of the corrosion resistance enhancement of artificially aged 7075 aluminium alloy using advanced Cs-corrected scanning transmission electron microscopy(STEM).The corrosion behaviors...This research studied the mechanism of the corrosion resistance enhancement of artificially aged 7075 aluminium alloy using advanced Cs-corrected scanning transmission electron microscopy(STEM).The corrosion behaviors of artificially aged 7075 aluminium alloys in a 3.5 wt.%NaCl solution were investigated by impedance spectra,equivalent circuit analyses,polarization measurements and immersion tests.The results show that a longer aging treatment leads to better corrosion resistance,which can be attributed to the following microstructural features,as revealed by STEM.The Cu segregation at grain boundaries under over-aged conditions helps retard intergranular corrosion.The Mg(Zn,Cu)_(2) precipitates formed on the surfaces of Al_(18)Mg_(3)(Cr,Mn)_(2) dispersoids effectively insulate the dispersoids as cathodes in corrosion,from the Al matrix.This study demonstrates a potential strategy to design corrosion-resistant alloys achieved by proper alloying and subsequent aging.展开更多
A magnetic fluid based deformable mirror(MFDM) that could produce a large stroke more than 100 μm is designed and demonstrated experimentally with respect to the characteristics of the aberration of the liquid telesc...A magnetic fluid based deformable mirror(MFDM) that could produce a large stroke more than 100 μm is designed and demonstrated experimentally with respect to the characteristics of the aberration of the liquid telescope. Its aberration correction performance is verified by the co-simulation using COMSOL and MATLAB. Furthermore, the stroke performance of the MFDM and the decentralized linear quadratic Gaussian(LQG) mirror surface control approach are experimentally evaluated with a prototype of MFDM in an adaptive optics system to show its potential application for the large aberration correction of liquid telescopes.展开更多
基金supported by the Open Fund of the State Key Laboratory of Refractories and Metallurgy,China(No.G201907)。
文摘This research studied the mechanism of the corrosion resistance enhancement of artificially aged 7075 aluminium alloy using advanced Cs-corrected scanning transmission electron microscopy(STEM).The corrosion behaviors of artificially aged 7075 aluminium alloys in a 3.5 wt.%NaCl solution were investigated by impedance spectra,equivalent circuit analyses,polarization measurements and immersion tests.The results show that a longer aging treatment leads to better corrosion resistance,which can be attributed to the following microstructural features,as revealed by STEM.The Cu segregation at grain boundaries under over-aged conditions helps retard intergranular corrosion.The Mg(Zn,Cu)_(2) precipitates formed on the surfaces of Al_(18)Mg_(3)(Cr,Mn)_(2) dispersoids effectively insulate the dispersoids as cathodes in corrosion,from the Al matrix.This study demonstrates a potential strategy to design corrosion-resistant alloys achieved by proper alloying and subsequent aging.
基金supported by the National Natural Science Foundation of China(No.51675321)the Shanghai Municipal Natural Science Foundation(No.15ZR1415800)the Innovation Program of Shanghai Municipal Education Commission(No.14ZZ092)
文摘A magnetic fluid based deformable mirror(MFDM) that could produce a large stroke more than 100 μm is designed and demonstrated experimentally with respect to the characteristics of the aberration of the liquid telescope. Its aberration correction performance is verified by the co-simulation using COMSOL and MATLAB. Furthermore, the stroke performance of the MFDM and the decentralized linear quadratic Gaussian(LQG) mirror surface control approach are experimentally evaluated with a prototype of MFDM in an adaptive optics system to show its potential application for the large aberration correction of liquid telescopes.
