Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
材料科学技术（英文）
The effect of interstitial hydrogen on the cohesion of the Al Sigma=11(113) grain boundary (GB) is investigated based on the thermodynamic model of Rice-Wang using the first-principles density function calculation. The results indicate that interstitial H behaves as an embrittler from "strengthening energy" analysis. The reduced GB cohesion due to the presence of H at the GB is attributed to the low affinity between H and Al, and the weakened bonding of Al atomic pairs perpendicular to GB plane.
关键词:
hydrogen;grain boundary;Al-Mg alloys;pseudopotentials;1st-principles
Xiaoguang LIU
,
Xiaowei WANG
材料科学技术（英文）
The effect of interstitial hydrogen on the cohesion of the Al ∑=11(113) grain boundary (GB) is investigated based on the thermodynamic model of Rice-Wang using the first-principles density function calculation. The results indicate that interstitial H behaves as an embrittler from "strengthening energy" analysis. The reduced GB cohesion due to the presence of H at the GB is attributed to the low affinity between H and Al, and the weakened bonding of Al atomic pairs perpendicular to GB plane.
关键词:
Hydrogen
,
null
,
null
Fresenius Environmental Bulletin
The relationship between existence of microbes and early corrosion behavior of mild steel in fresh waters was studied using immersion tests, electrochemical measurements and surface analysis techniques. In the field immersion test at Dan Jiangkou reservoir in China, mild steel had less corrosion weight loss in the upper layer of water, where more microbes existed. The accumulation of microbes on the surface of coupons was thought to slow down the corrosion rate by restricting the oxygen diffusion and other factors. This hypothesis was confirmed by the electrochemical measurements and immersion test in natural freshwater. The results of the Scanning Electron Microscopy (SEM) and Fourier Transform Infra-red (FT-IR) spectra further confirmed that the existence of microbes could affect the formation of the corrosion products. Furthermore, the surface film formed in microbes-contained freshwater was thicker and with more complex corrosion products.
关键词:
Corrosion;freshwater;eutrophication;microbes;mild steel;microbiologically influenced corrosion;biocorrosion
Physical Review B
By use of the linear-combination-of-atomic-orbital (LCAO) method for a cluster model, we studied the electronic structure of gamma-from Sigma 11 [1 (1) over bar0](11 (3) over bar) grain boundary doping with N and Mn atoms. The effect of the segregation on the cohesion of the grain boundary is investigated based on the Rice-Wang thermodynamic model. It is found that N could not only largely enhance the cohesion of the grain boundary but also eliminate the detrimental effect of Mn. The cosegregation effect of Mn and N on the cohesion of the grain boundary depends on where they segregate. Nitrogen could be reliably used in alloyed steels as an efficient strengthening element.
关键词:
electronic-structure;phosphorus segregation;stainless-steel;embrittlement;austenite;nitrogen;boron;impurities;fracture;metals
衷诚武
,
叶奇
,
简炜炜
钛工业进展
doi:10.3969/j.issn.1009-9964.2007.02.006
通过有机镀膜技术,对镁合金表面进行改性.对有机镀膜处理后的镁合金表面的接触角,表面自由能进行了测定.研究了不同有机镀液,在恒电流作用下,有机镀膜时间对镁合金表面性能的影响.结果表明,经过TTN溶液有机镀膜后,镁合金板表现出亲水性,其表面能比未处理镁合金板的表面自由能要高;而经过DHN和DAN溶液有机镀膜后,镁合金板表现出良好的疏水性,其表面能比未处理镁合金板的表面自由能要低,在二者中DHN处理后的疏水效果最好.实现了对镁合金表面疏水、亲水表面改性,能够很好的扩大镁合金在工业中的应用领域.
关键词:
镁合金
,
有机镀膜
,
亲水薄膜
,
疏水薄膜
张金艳
,
肖小明
,
蒋艳
,
谭年元
应用化学
doi:10.3724/SP.J.1095.2010.90729
在微波辐射和无催化剂条件下,由吡啶2,6-二甲酸与乙二胺反应合成了2,6-二(2′-咪唑啉-2′-基)吡啶(L),采用常规加热法合成其配合物[CrL2][NO3]3. 用核磁共振、红外光谱、元素分析、热重分析和摩尔电导率测试技术对其进行表征分析. 通过紫外吸收光谱和黏度测试,分别考察了配体及配合物与DNA的键合常数及其作用方式. 结果表明,配体L以氢键和沟面作用方式与DAN键合,而配合物以氢键和静电作用模式与DNA键合. 密度泛函理论(DFT)计算结果较好的解释了L及[CrL2]3+与DNA的相互作用模式.
关键词:
二(咪唑啉基)吡啶
,
铬配合物
,
DNA
,
微波辐射
,
DFT
Journal of Physics and Chemistry of Solids
The layered ternary ceramics Ti3SiC2 and Ti3AlC2 are isostructural and can form Ti3Si1-xAlxC2 solid solutions combining the advanced properties of both compounds [H.B. Zhang, Y.C. Zhou, Y.W. Bao, M.S. Li, Improving the oxidation resistance of Ti3SiC2 by forming a Ti3Si0.90Al0.1C2 solid solution, Acta Mater. 52 (2004) 3631-3637; E.D. Wu, J.Y. Wang, H.B. Zhang, Y.C. Zhou, K. Sun, Y.J. Xue, Neutron diffraction studies of Ti3Si0.9Al0.1C2 compound, Mater. Lett. 59 (2005) 2715-2719; J.Y. Wang, Y.C. Zhou, First-principles study of equilibrium properties and electronic structure of Ti3Si0.75Al0.25C2 solid solution, J. Phys.: Condens. Matter 15 (2003) 5959-5968; Y.C. Zhou, J.X. Chen, J.Y. Wang, Strengthening of Ti3AlC2 by incorporation of Si to form Ti3Al1-xSixC2 solid solutions, Acta. Mater. 54 (2006) 1317-1322]. In the present work, the solid solutions of Ti3Si1-xAlxC2 (x = 0, 0.25, 0.33, 0.5, 0.67, 0.75, 1) are investigated by first-principle calculations based on pseudo-potential plan-wave method within the density functional theory framework. The results show that as Al content increases in the solid solution, all the bonds have weakened to certain extents, which lead to an unstable structure both energetically and geometrically. The calculated results are compared and discussed with the reported data for the Ti3Si1-xAlxC2 solid solutions. (c) 2007 Elsevier Ltd. All rights reserved.
关键词:
ceramics;ab initio calculations;electronic structure;electrical;conductivity;oxidation behavior;mechanical-properties;ti3sic2;temperature;ti3alc2;air;si
