材料期刊网

Formation of Mn+1AXn phases in Ti-Cr-Al-C systems by self-propagating high-temperature synthesis

Guo-Bing Ying , Xiao-Dong He , Shan-Yi Du , Chun-Cheng Zhu , Yong-Ting Zheng , Yu-Ping Wu , Cheng Wang

稀有金属 doi:10.1007/s12598-013-0196-9

关键词:

Kinetics and numerical simulation of self-propagating high-temperature synthesis in Ti-Cr-Al-C systems

Guo-Bing Ying , Xiao-Dong He , Shan-Yi Du , Yong-Ting Zheng , Chun-Cheng Zhu , Yu-Ping Wu , Cheng Wang

稀有金属 doi:10.1007/s12598-013-0205-z

关键词:

Two-step magnetization in a spin-chain system on the triangular lattice: Wang-Landau simulation

Physical Review B

The Wang-Landau algorithm is used to study the thermodynamic and magnetic properties of triangular spin-chain system based on two-dimensional Ising model in order to understand the magnetic-order dynamics in Ca(3)Co(2)O(6) compound. The calculated results demonstrate that the equilibrium state of the rigid spins produces the two-step magnetization curve at low temperature even when the random-exchange term is considered. This work indicates that the four-step magnetization behavior observed experimentally must be due to the nonequilibrium magnetization.

关键词: calcium compounds;exchange interactions (electron);Ising model;magnetisation;thermodynamics;one-dimensional ca3co2o6;density-of-states;compound ca3co2o6;phase-diagram;proteins;crystal

Ion sputter erosion in metallic glass-A response to "Comment on: Homogeneity of Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass" by L-Y. Chen, Y-W. Zeng, Q-P. Cao, B-J. Park, Y-M. Chen, K. Hono, U. Vainio, Z-L. Zhang, U. Kaiser, X-D. Wang, and J-Z Jiang J. Mater. Res. 24, 3116 (2009)

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

纳米复合薄膜特异电容机制探讨

程开甲 , 程漱玉 , 林东升 , 肖刚

稀有金属材料与工程

TFDC(Thomas-Fermi-Dirac-Cheng)electron theory用于分析讨论了纳米复合薄膜二极层中电子的特性.根据TFDC电子理论研究和实验测试提出了纳米复合薄膜二极层特异电容产生的机制.

关键词: TFDC电子理论 , 二极层 , 大电容 , 薄膜

论位错的稳定存在

程开甲 , 程漱玉

稀有金属材料与工程

阐述了Thomas-Fermi-Dirac-Cheng电子理论的位错形成机制. 通过对系统总能量的分析提出了位错能够存在的判据, 计算给出多种单质材料位错存在的极限尺寸值.

关键词: 位错 , Thomas-Fermi-Dirac-Cheng , 极限尺寸

论薄膜的超导电性

程开甲 , 程漱玉

稀有金属材料与工程

应用Cheng-Born能带对称破缺理论和TFDC(Thomas-Fermi-Dirac-Cheng)电子理论研究了薄膜层内电子的特性.对金属铂上的TiO2膜层来说,TFDC理论指出电子(或空穴)将由金属与膜的间界面一侧迁移到另一侧.根据Cheng-Born对称破缺理论,当能带中只有很少的电子时,则只有极少的角区中存在电子,动量空间即产生对称破缺,从而导致超导电性,并由热力学估算出薄膜超导体的转变温度.结果显示薄膜超导体的转变温度至少比块材超导体的转变温度高一个量级.作者还设计了一个研究薄膜超导电性的实验.

关键词: 超导电性 , 薄膜 , 对称破缺 , TFDC

论共晶结构的机理

程开甲 , 程漱玉

稀有金属材料与工程

本文是Thomas-Fermi-Dirac-Cheng电子理论对共晶机理的阐述.提出了薄膜两组元之间的化学势差和电子密度差导致系统总能量改变的新思想,给出了研究稳定共晶态的最佳尺寸和能量的方法.

关键词: Thomas-Fermi-Dirac , 共晶 , 内应力 , 化学势 , 电子密度

泡沫混凝土导热系数模型及参数修正

李翔宇 , 赵霄龙 , 郭向勇 , 曹力强

材料导报

在Cheng-Vachon模型的基础上提出了一种针对由连续相和分散相组成的两相复合材料的新导热系数模型.通过引入一个新的参数,即分散相的修正体积含量来改进Cheng-Vachon模型不适用于分散相体积含量较大的缺点.使用新的导热系数模型预测泡沫混凝土的导热系数,与实验结果的对比表明,新的模型可以准确预测泡沫混凝土的导热系数.

关键词: 泡沫混凝土 , 复合材料 , 导热系数 , 无机材料

Effect of interstitial hydrogen on cohesive strength of Al grain boundary with Mg segregation

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