The influence rules of square micro-pillar array porosity on the liquid motion characteristics of the near-surface layer are investigated by quartz crystal microbalance(QCM).QCM is a powerful and promising technique i...The influence rules of square micro-pillar array porosity on the liquid motion characteristics of the near-surface layer are investigated by quartz crystal microbalance(QCM).QCM is a powerful and promising technique in studying the interfacial behavior,which exhibits great advantages in investigating the effects of surface microstructure,roughness,and array.In our experiments,three different arrays with the same height of about 280 nm and center distance of 200μm,but different diameters of about 78μm,139μm,and 179μm are investigated.The results indicate that when the surface array has a large porosity,its influence on the liquid motion of the near surface layer is slight,thus resulting in a small increase of half-bandwidth variation due to the additional friction energy dissipation.When the surface array has a small porosity,the array tends to make the liquid film trapped in the array oscillating with the substrate,then there may be a layer of liquid film behaving like rigid film,and it also will make the liquid motion near the array layer more complicated.Thus for the#3 surface with a small porosity,both the absolute values of frequency shift|Δf3|and half-bandwidth variationΔΓ3 increase obviously.The experimental results show good consistence with the theoretical model of Daikhin and Urbakh.This study sheds light on understanding the influence mechanism of surface array porosity on the liquid motion of near-surface layer.展开更多
Although using the microstructure of a surface to enhance specific functions has immense applicability in numerous fields,few studies have been conducted on the multi-functional properties of nuclear fuel elements in ...Although using the microstructure of a surface to enhance specific functions has immense applicability in numerous fields,few studies have been conducted on the multi-functional properties of nuclear fuel elements in harsh environments.In this study,surfaces with zirconium alloy micro-pillar arrays were prepared using micro-milling and ultraviolet nanosecond laser technology,and their functional properties such as the wettability,structural stability,and corrosion resistance were investigated.It was found that the geometric dimension of the micro-pillar arrays prepared using these two methods could meet the design requirements,but the micro-milling process had the best dimensional accuracy.Micro-nano multi-scale structures were obtained by laser ablation.However,these multi-scale structures exhibited weak structural stability,and the nanostructures were easily corroded.By contrast,the micro-pillar arrays manufactured using micro-milling were confirmed to have better structural stability and corrosion resistance.On one hand,the area mass loss of the micro-milled structure was lower than that of a flat surface after experiencing high-pressure fluid scouring at 8 and 38 m/s.On the other hand,the oxidation weight gain of the surface with the micro-milled structure was lower than that of a flat surface,and the oxide film was 22.5% thinner after 100 days of deionized water corrosion at 360℃ and 18.7 MPa.展开更多
An α/β two-phase Ti-6Al-4V alloy was fabricated by electron beam melting to obtain a basketweave structure.The orientation dependence of the mechanical properties of Ti-6Al-4 V alloy was studied by micro-pillar comp...An α/β two-phase Ti-6Al-4V alloy was fabricated by electron beam melting to obtain a basketweave structure.The orientation dependence of the mechanical properties of Ti-6Al-4 V alloy was studied by micro-pillar compression and post-mortem transmission electron microscopy analysis.The results indicate that different grains have different mechanical responses,and the possible attributions were discussed.Besides the orientation effect,due to the limited volumes of micropillars,the size of the a phases,dispersion of the β phases,and the presence of the free dislocation path also affect the mechanical properties of the micropillars to a large extent.Although no direct link was discovered between the mechanical properties and the parent β orientations,this work provided a promising method to further study the anisotropic mechanical behavior in Ti-6Al-4V alloy.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.51905032)the National Key Research and Development Program of China(Grant No.2018YFC0810500)the Fundamental Research Funds for the Central Universities,China(Grant No.FRF-TP-18-012A2).
文摘The influence rules of square micro-pillar array porosity on the liquid motion characteristics of the near-surface layer are investigated by quartz crystal microbalance(QCM).QCM is a powerful and promising technique in studying the interfacial behavior,which exhibits great advantages in investigating the effects of surface microstructure,roughness,and array.In our experiments,three different arrays with the same height of about 280 nm and center distance of 200μm,but different diameters of about 78μm,139μm,and 179μm are investigated.The results indicate that when the surface array has a large porosity,its influence on the liquid motion of the near surface layer is slight,thus resulting in a small increase of half-bandwidth variation due to the additional friction energy dissipation.When the surface array has a small porosity,the array tends to make the liquid film trapped in the array oscillating with the substrate,then there may be a layer of liquid film behaving like rigid film,and it also will make the liquid motion near the array layer more complicated.Thus for the#3 surface with a small porosity,both the absolute values of frequency shift|Δf3|and half-bandwidth variationΔΓ3 increase obviously.The experimental results show good consistence with the theoretical model of Daikhin and Urbakh.This study sheds light on understanding the influence mechanism of surface array porosity on the liquid motion of near-surface layer.
基金supported by the National Natural Science Foundation of China (Grant Nos.U19A2077&12105273)。
文摘Although using the microstructure of a surface to enhance specific functions has immense applicability in numerous fields,few studies have been conducted on the multi-functional properties of nuclear fuel elements in harsh environments.In this study,surfaces with zirconium alloy micro-pillar arrays were prepared using micro-milling and ultraviolet nanosecond laser technology,and their functional properties such as the wettability,structural stability,and corrosion resistance were investigated.It was found that the geometric dimension of the micro-pillar arrays prepared using these two methods could meet the design requirements,but the micro-milling process had the best dimensional accuracy.Micro-nano multi-scale structures were obtained by laser ablation.However,these multi-scale structures exhibited weak structural stability,and the nanostructures were easily corroded.By contrast,the micro-pillar arrays manufactured using micro-milling were confirmed to have better structural stability and corrosion resistance.On one hand,the area mass loss of the micro-milled structure was lower than that of a flat surface after experiencing high-pressure fluid scouring at 8 and 38 m/s.On the other hand,the oxidation weight gain of the surface with the micro-milled structure was lower than that of a flat surface,and the oxide film was 22.5% thinner after 100 days of deionized water corrosion at 360℃ and 18.7 MPa.
文摘An α/β two-phase Ti-6Al-4V alloy was fabricated by electron beam melting to obtain a basketweave structure.The orientation dependence of the mechanical properties of Ti-6Al-4 V alloy was studied by micro-pillar compression and post-mortem transmission electron microscopy analysis.The results indicate that different grains have different mechanical responses,and the possible attributions were discussed.Besides the orientation effect,due to the limited volumes of micropillars,the size of the a phases,dispersion of the β phases,and the presence of the free dislocation path also affect the mechanical properties of the micropillars to a large extent.Although no direct link was discovered between the mechanical properties and the parent β orientations,this work provided a promising method to further study the anisotropic mechanical behavior in Ti-6Al-4V alloy.
