Hydrogen-induced cracking was investigated by TEM in-situ tension in hydrogenated stainless steel of type 310. It was found experimentally that hydrogen-induced cracking happens via nanovoid nucleation followed by qua...Hydrogen-induced cracking was investigated by TEM in-situ tension in hydrogenated stainless steel of type 310. It was found experimentally that hydrogen-induced cracking happens via nanovoid nucleation followed by quasi-cleavage along {111} planes when C H is higher. Otherwise, in the case of lower C H, hydrogen enhances ductile fracture via hydrogen-enhanced microvoid nucleation, growth and connection. A new model was proposed based on the present experiments. Dislocations break away from defect atmospheres and move away from the DFZ, leaving vacancy and hydrogen clusters along {111} planes. Hydrogen tends to combine with vacancy clusters and initiate nanovoids along {111} planes. Dense nanovoids connect each other, resulting in brittle cracking. Scattered nanovoids grow into microvoids or even macrovoids, leading to ductile fracture.展开更多
In this paper, the gettering of Cu impurities in silicon-on-insulator (SOI) materials is studied. Nanovoids are formed in the substrate of SOI beneath the buried oxide (BOX) by room temperature H+ (3.51016 /cm2 ) or H...In this paper, the gettering of Cu impurities in silicon-on-insulator (SOI) materials is studied. Nanovoids are formed in the substrate of SOI beneath the buried oxide (BOX) by room temperature H+ (3.51016 /cm2 ) or He+ (91016 /cm2 ) implantation and subsequent annealing at 700oC. The gettering of different doses of Cu (51013/cm2, 51014 /cm2, 51015/cm2), which are introduced in the top Si layer by ion implantation, to the nanovoids are investigated by cross-section transmission electron microscopy (XTEM) and secondary ion mass spectroscopy (SIMS). The results demonstrate that Cu impurities in the top Si layer can diffuse through the bur-ied oxide (BOX) layer of SIMOX and Smart-Cut SOI at temperature above 700oC and be trapped by the nanovoids. Some of Cu impurities can be captured by the intrinsic defects at the BOX inter-face of SIMOX, but will be released out at high temperatures. The gettering effect of SIMOX intrin-sic defects at BOX is much lower than that of the nanovoids. No Cu impurities are trapped at the perfect BOX interfaces of Smart-Cut SOI. After 1000℃ annealing, high dose of Cu (3.61015 /cm2) was gettered by the nanovoids. The Cu gettering efficiency to the nanovoids increased with the decreasing of Cu doses. When the Cu doses in the top Si layer were lower than 41015 /cm2, the nanovoids could getter more than 90% of the Cu impurities and reduce the Cu concentration in the top Si layer to less than 4%. The results indicate that nanovoids gettering is a promising method for removing the impurities in SOI materials.展开更多
Here,we report the synthesis of hard carbon materials(RH) made from natural rice husk through a single pyrolysis process and their application as an anode in sodium-ion batteries.The studies show that the electrochemi...Here,we report the synthesis of hard carbon materials(RH) made from natural rice husk through a single pyrolysis process and their application as an anode in sodium-ion batteries.The studies show that the electrochemical properties of RHs are affected by the treatment temperatures,which determine the materials morphology,in particular,their degree of graphitization and extent of continuous channels(nanovoids).The latter are accessible to sodium ions and significantly contribute to charge storage capacity of the produced anodes.The RHs obtained at 1600 °C deliver the highest reversible capacity of276 mAh g^(-1) mainly due to insertion of sodium ions into the nanovoids.This work deepens the basic understanding of the influence of the carbonization temperature on the sodium storage mechanism.展开更多
离子辐照是控制金属纳米颗粒分布和结构的有效方法。将能量为200 keV、剂量为5×10^(16)ions/cm^2的Ag^+注入到非晶SiO_2中,形成Ag纳米颗粒层,再用能量为200和500 ke V的Ar^+辐照Ag纳米颗粒。Ar^+辐照后,在部分较大的Ag纳米颗粒中...离子辐照是控制金属纳米颗粒分布和结构的有效方法。将能量为200 keV、剂量为5×10^(16)ions/cm^2的Ag^+注入到非晶SiO_2中,形成Ag纳米颗粒层,再用能量为200和500 ke V的Ar^+辐照Ag纳米颗粒。Ar^+辐照后,在部分较大的Ag纳米颗粒中出现空洞,空洞的平均尺寸随着Ar^+辐照剂量的增加而变大。辐照前,Ag纳米颗粒在非晶SiO_2中沿纵向呈近似高斯分布;辐照后,投影射程附近的较大的Ag纳米颗粒平均尺寸变大,而投影射程下面的小颗粒逐渐消失。结合Trim程序模拟分析结果可知,Ar^+辐照时的核能量损失和电子能量损失是影响Ag纳米颗粒尺寸分布和结构的重要因素。展开更多
The plastic deformation properties of cylindrical pre-void aluminum-magnesium(Al-Mg)alloy under uniaxial tension are explored using molecular dynamics simulations with embedded atom method(EAM)potential.The factors of...The plastic deformation properties of cylindrical pre-void aluminum-magnesium(Al-Mg)alloy under uniaxial tension are explored using molecular dynamics simulations with embedded atom method(EAM)potential.The factors of Mg content,void size,and temperature are considered.The results show that the void fraction decreases with increasing Mg in the plastic deformation,and it is almost independent of Mg content when Mg is beyond 5%.Both Mg contents and stacking faults around the void affect the void growth.These phenomena are explained by the dislocation density of the sample and stacking faults distribution around the void.The variation trends of yield stress caused by void size are in good agreement with the Lubarda model.Moreover,temperature effects are explored,the yield stress and Young’s modulus obviously decrease with temperature.Our results may enrich and facilitate the understanding of the plastic mechanism of Al-Mg with defects or other alloys.展开更多
文摘Hydrogen-induced cracking was investigated by TEM in-situ tension in hydrogenated stainless steel of type 310. It was found experimentally that hydrogen-induced cracking happens via nanovoid nucleation followed by quasi-cleavage along {111} planes when C H is higher. Otherwise, in the case of lower C H, hydrogen enhances ductile fracture via hydrogen-enhanced microvoid nucleation, growth and connection. A new model was proposed based on the present experiments. Dislocations break away from defect atmospheres and move away from the DFZ, leaving vacancy and hydrogen clusters along {111} planes. Hydrogen tends to combine with vacancy clusters and initiate nanovoids along {111} planes. Dense nanovoids connect each other, resulting in brittle cracking. Scattered nanovoids grow into microvoids or even macrovoids, leading to ductile fracture.
基金supported by the National Natural Science Foundation of China (Grant No. 69906005) and Shanghai Youth Foundation under grant No. 01QMH1403. The authors would like to thank Prof. P. F. P. Fichtner at Universidade do Rio Grande do Sul Brazil for the TEM an
文摘In this paper, the gettering of Cu impurities in silicon-on-insulator (SOI) materials is studied. Nanovoids are formed in the substrate of SOI beneath the buried oxide (BOX) by room temperature H+ (3.51016 /cm2 ) or He+ (91016 /cm2 ) implantation and subsequent annealing at 700oC. The gettering of different doses of Cu (51013/cm2, 51014 /cm2, 51015/cm2), which are introduced in the top Si layer by ion implantation, to the nanovoids are investigated by cross-section transmission electron microscopy (XTEM) and secondary ion mass spectroscopy (SIMS). The results demonstrate that Cu impurities in the top Si layer can diffuse through the bur-ied oxide (BOX) layer of SIMOX and Smart-Cut SOI at temperature above 700oC and be trapped by the nanovoids. Some of Cu impurities can be captured by the intrinsic defects at the BOX inter-face of SIMOX, but will be released out at high temperatures. The gettering effect of SIMOX intrin-sic defects at BOX is much lower than that of the nanovoids. No Cu impurities are trapped at the perfect BOX interfaces of Smart-Cut SOI. After 1000℃ annealing, high dose of Cu (3.61015 /cm2) was gettered by the nanovoids. The Cu gettering efficiency to the nanovoids increased with the decreasing of Cu doses. When the Cu doses in the top Si layer were lower than 41015 /cm2, the nanovoids could getter more than 90% of the Cu impurities and reduce the Cu concentration in the top Si layer to less than 4%. The results indicate that nanovoids gettering is a promising method for removing the impurities in SOI materials.
基金the COST Association and COST Action CA15107 "MultiFunctional Nano-Carbon Composite Materials Network (MultiComp)" for the financial supportRoyal Society via the Newton Fund for an Advanced Newton Fellowship at Queen Mary University of London which triggered this collaboration
文摘Here,we report the synthesis of hard carbon materials(RH) made from natural rice husk through a single pyrolysis process and their application as an anode in sodium-ion batteries.The studies show that the electrochemical properties of RHs are affected by the treatment temperatures,which determine the materials morphology,in particular,their degree of graphitization and extent of continuous channels(nanovoids).The latter are accessible to sodium ions and significantly contribute to charge storage capacity of the produced anodes.The RHs obtained at 1600 °C deliver the highest reversible capacity of276 mAh g^(-1) mainly due to insertion of sodium ions into the nanovoids.This work deepens the basic understanding of the influence of the carbonization temperature on the sodium storage mechanism.
文摘离子辐照是控制金属纳米颗粒分布和结构的有效方法。将能量为200 keV、剂量为5×10^(16)ions/cm^2的Ag^+注入到非晶SiO_2中,形成Ag纳米颗粒层,再用能量为200和500 ke V的Ar^+辐照Ag纳米颗粒。Ar^+辐照后,在部分较大的Ag纳米颗粒中出现空洞,空洞的平均尺寸随着Ar^+辐照剂量的增加而变大。辐照前,Ag纳米颗粒在非晶SiO_2中沿纵向呈近似高斯分布;辐照后,投影射程附近的较大的Ag纳米颗粒平均尺寸变大,而投影射程下面的小颗粒逐渐消失。结合Trim程序模拟分析结果可知,Ar^+辐照时的核能量损失和电子能量损失是影响Ag纳米颗粒尺寸分布和结构的重要因素。
基金supported by the National Natural Science Foundation of China(Grant No.11502217)the Fundamental Research Funds for the Central Universities(Grant Nos.2452015054,2452017122,and JUSRP121042)+3 种基金the China Postdoctoral Science Foundation(Grant Nos.2015M570854 and 2016T90949)the Projects of the Manned Space Engineering Technology(Grant No.2020ZKZX-5011)Development of Large-Scale Spacecraft Flight and Reentry Surveillance and Prediction System,the Open Fund of Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education(NUAA)(Grant No.INMD-2019M08)Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology(Grant Nos.FMZ202001 and FMZ202009)。
文摘The plastic deformation properties of cylindrical pre-void aluminum-magnesium(Al-Mg)alloy under uniaxial tension are explored using molecular dynamics simulations with embedded atom method(EAM)potential.The factors of Mg content,void size,and temperature are considered.The results show that the void fraction decreases with increasing Mg in the plastic deformation,and it is almost independent of Mg content when Mg is beyond 5%.Both Mg contents and stacking faults around the void affect the void growth.These phenomena are explained by the dislocation density of the sample and stacking faults distribution around the void.The variation trends of yield stress caused by void size are in good agreement with the Lubarda model.Moreover,temperature effects are explored,the yield stress and Young’s modulus obviously decrease with temperature.Our results may enrich and facilitate the understanding of the plastic mechanism of Al-Mg with defects or other alloys.
基金the support from National Natural Science Foundation of China(Grant No.11872139)Nian Zhou appreciates the supportfrom Guizhou Provincial Departmentof Education(Grant No.KY[2021]255).
