The effects of trace Ag element on the precipitation behaviors and mechanical properties of the Mg−7.5Gd−1.5Y−0.4Zr(wt.%)alloy by means of tensile test,X-ray diffractometry,scanning electron microscopy,electron backsc...The effects of trace Ag element on the precipitation behaviors and mechanical properties of the Mg−7.5Gd−1.5Y−0.4Zr(wt.%)alloy by means of tensile test,X-ray diffractometry,scanning electron microscopy,electron backscattered diffractometry,and scanning transmission electron microscopy.There is an unusual texture(á0001ñ//extrusion direction)in the extruded Mg−Gd−Y−Zr alloys containing 0.5 wt.%Ag.During the aging periods at 225℃,the addition of the trace Ag does not form new precipitates,just accelerates aging kinetics,and refinesβ′precipitates,thereby increasing the number density of theβ′precipitates by Ag-clusters.Moreover,the Mg−Gd−Y−Zr alloy containing 0.5 wt.%Ag shows the most excellent synergy of strength and plasticity(408 MPa of ultimate tensile strength,265 MPa of yield strength,and 12.9%of elongation to failure)after peak-aging.展开更多
Two kinds of high pure silver materials with 5.3 ppm oxygen and 32.7 ppm oxygen were prepared by various melting processes, both samples were subjected to accumulative rolling with 95% thickness reduction. Their mecha...Two kinds of high pure silver materials with 5.3 ppm oxygen and 32.7 ppm oxygen were prepared by various melting processes, both samples were subjected to accumulative rolling with 95% thickness reduction. Their mechanical properties were tested during long natural aging. Results showed that the Ag sheet with 5.3 ppm oxygen is at full annealed state when natural aging 58 days or kept at 150℃ for 30 minutes, and the Ag sheet with 32.7 ppm oxygen is a little of recovery when natural aging a year. It is suggested that appropriate oxygen interstitial solute in Ag solid solution and a few of Ag2O particles at Ag grain boundaries impede the recovery and recrystallization of Ag sheets.展开更多
The hazard of Hg ion pollution triggers the motivation to explore a fast, sensitive, and reliable detection method. Here, we design and fabricate novel 36-nm-thick Ag-Au composite layers alternately deposited on three...The hazard of Hg ion pollution triggers the motivation to explore a fast, sensitive, and reliable detection method. Here, we design and fabricate novel 36-nm-thick Ag-Au composite layers alternately deposited on three-dimensional （3D） periodic SiO2 nanogrids as surface-enhanced Raman scattering （SERS） probes. The SERS effects of the probes depend mainly on the positions and intensities of their localized surface plasmon resonance （LSPR） peaks, which is confirmed by the absorption spectra from finite-difference time-domain （FDTD） calculations. By optimizing the structure and material to maximize the intrinsic electric field enhancement based on the design method of 3D periodic SERS probes proposed, high performance of the Ag-Au/SiO2 nanogrid probes is achieved with the stability further enhanced by annealing. The optimized probes show the outstanding stability with only 4.0% SERS intensity change during 10-day storage, the excellent detection uniformity of 5.78% （RSD）, the detection limit of 5.0 × 10-12 M （1 ppt）, and superior selectivity for Hg ions. The present study renders it possible to realize the rapid and reliable detection of trace heavy metal ions by developing high- performance 3D periodic structure SERS probes by designing novel 3D structure and optimizing plasmonic material.展开更多
基金financial supports from the National Natural Science Foundation of China (Nos. 51574291, 51874367)。
文摘The effects of trace Ag element on the precipitation behaviors and mechanical properties of the Mg−7.5Gd−1.5Y−0.4Zr(wt.%)alloy by means of tensile test,X-ray diffractometry,scanning electron microscopy,electron backscattered diffractometry,and scanning transmission electron microscopy.There is an unusual texture(á0001ñ//extrusion direction)in the extruded Mg−Gd−Y−Zr alloys containing 0.5 wt.%Ag.During the aging periods at 225℃,the addition of the trace Ag does not form new precipitates,just accelerates aging kinetics,and refinesβ′precipitates,thereby increasing the number density of theβ′precipitates by Ag-clusters.Moreover,the Mg−Gd−Y−Zr alloy containing 0.5 wt.%Ag shows the most excellent synergy of strength and plasticity(408 MPa of ultimate tensile strength,265 MPa of yield strength,and 12.9%of elongation to failure)after peak-aging.
文摘Two kinds of high pure silver materials with 5.3 ppm oxygen and 32.7 ppm oxygen were prepared by various melting processes, both samples were subjected to accumulative rolling with 95% thickness reduction. Their mechanical properties were tested during long natural aging. Results showed that the Ag sheet with 5.3 ppm oxygen is at full annealed state when natural aging 58 days or kept at 150℃ for 30 minutes, and the Ag sheet with 32.7 ppm oxygen is a little of recovery when natural aging a year. It is suggested that appropriate oxygen interstitial solute in Ag solid solution and a few of Ag2O particles at Ag grain boundaries impede the recovery and recrystallization of Ag sheets.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0207104)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA09040101)+2 种基金the National Natural Science Foundation of China(Grant No.Y6061111JJ)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2015030)the Key Technology Talent Program of Chinese Academy of Sciences(Grant Nos.Y8482911ZX and Y7602921ZX)
文摘The hazard of Hg ion pollution triggers the motivation to explore a fast, sensitive, and reliable detection method. Here, we design and fabricate novel 36-nm-thick Ag-Au composite layers alternately deposited on three-dimensional （3D） periodic SiO2 nanogrids as surface-enhanced Raman scattering （SERS） probes. The SERS effects of the probes depend mainly on the positions and intensities of their localized surface plasmon resonance （LSPR） peaks, which is confirmed by the absorption spectra from finite-difference time-domain （FDTD） calculations. By optimizing the structure and material to maximize the intrinsic electric field enhancement based on the design method of 3D periodic SERS probes proposed, high performance of the Ag-Au/SiO2 nanogrid probes is achieved with the stability further enhanced by annealing. The optimized probes show the outstanding stability with only 4.0% SERS intensity change during 10-day storage, the excellent detection uniformity of 5.78% （RSD）, the detection limit of 5.0 × 10-12 M （1 ppt）, and superior selectivity for Hg ions. The present study renders it possible to realize the rapid and reliable detection of trace heavy metal ions by developing high- performance 3D periodic structure SERS probes by designing novel 3D structure and optimizing plasmonic material.
