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CRYSTALLOGRAPHIC PROPERTIES OF AN INHERENT LOW-ENERGY INTERFACE (11)Cu//(0001)_(AIN) IN Cu-AlN BICRYSTAL

J. Du , G.Y.Yang and S. Hagegege(General Research Institute for Non-ferrous Metals , Beijing 100088 , China)(CECM-CNRS , 15 rue G. Urbain , 94407 Vitry/Seine , France Manuscript received 25 September 1995)

金属学报(英文版)

A model Cu-AlN composite has been prepared by ion implantation technique and annealing. The atomic configuration and lattice relationship of a low-energy inherent interface(11)Cn//(0001)AlN were studied by using transmission electron microscopy and geometrical modelling. By analysing the dichromatic pattern of the composite,a primary structural unit of the interface atomic configuration was determined for purpose of HREM image simulations and of studying the structurul relaxation state in the near-interface region.

关键词: : Cu-AlN , null , null , null

Manuscript Requirements

新型炭材料

关键词:

钢管内涂标准SY/T 4078-1995应尽快修订

何浩 , 王献昉 , 金华

腐蚀与防护 doi:10.3969/j.issn.1005-748X.2004.09.012

石油天然气行业标准SY/T 4078-1995<钢质管道内涂层液体涂料补口机补口工艺>在适用范围、焊口表面处理、现场施工过程及焊口补口涂层检验等部分都有不妥之处.成功的工程实例表明:无溶剂环氧树脂作为管线内壁涂层的补口涂料是非常合适的,它可以使传统的补口工艺更加科学、合理.为保证钢管内壁涂层的整体质量应尽快予以修订该行业标准.

关键词: 石油天然气 , 行业标准 , 管线 , 无溶剂环氧树脂 , 涂层

Mechanical alloying and characterization of Ni50Al25Ti25

Journal of Alloys and Compounds

An amorphous-like phase, the mixture of amorphous phase and microcrystalline beta-Ni(Al,Ti) compound, has been synthesized by mechanically alloying the Ni50Al25Ti25 elemental powder mixtures in a high energy ball mill. It has been found that titanium plays a dominant role in this process. There exist two types of transformations of amorphous-like Ni50Al25Ti25 upon heating: first, the amorphous-like alloy transforms into a disordered Ni2AlTi compound (b.c.c. structure) at 345-445 degrees C, and then into an ordered Ni2AlTi compound at 554-626 degrees C. Tt is suggested that at the low-temperature transition, the Ni atoms locate in the corners of the b.c.c. lattice, but the cubic centers are occupied randomly by Al and Ti atoms. When the temperature rises to 554 degrees C, a long-range ordering transition occurs, resulting in the formation of ordered Ni2AlTi. The ordering energy of Ni2AlTi has been measured as 4.35 kJ mol(-1).

关键词: mechanical alloying;phase transition;Ni-Al-Ti alloys;intermetallic compounds

Superplasticity in a directionally solidiried multiphase Ni-25Al-25Cr alloy

Zeitschrift Fur Metallkunde

A Ni-25Al-25Cr (at.%) alloy was directionally solidified under Ar atmosphere in an A1(2)O(3)-SiO2 ceramic mold by the standard Bridgman method. The microstructure of the as-fabricated alloy was studied using optical microscopy, X-ray diffraction and scanning electron microscopy. The alloy was composed of beta-NiAl dendritic arms, alpha-Cr interdendritic regions, fine alpha-Cr particles in the dendritic arms, and beta-NiAl + alpha-Cr eutectic in the interdendritic regions. The mechanical properties were studied by tensile tests in the temperature range 1123 - 1373 K. The results showed that the alloy exhibits superplastic behavior at appropriate testing conditions. The balance between work hardening (by dislocation glide) and work softening (by dynamic recovery and recrystallization) is responsible for the large tensile elongation of the alloy.

关键词: NiAl;superplastic behavior;casting;microstructure;internal-stress superplasticity;polycrystalline materials;large;grains;transformation;deformation;microstructure;intermetallics;mechanism;creep;iron

Microstructure and properties of vacuum induction melted CuCr25 alloys

Journal of Alloys and Compounds

The CuCr25 alloys prepared by vacuum induction melting (VIM) were investigated. The experimental results show that W and Ni had significant influence on the microstructure of CuCr25 alloys. For CuCr25Ni0.5 and CuCr25W1 alloys, the Cr phase was dramatically refined and presented nodular morphology. W could increase the breakdown strength of CuCr25. The electric conductivity of CuCr25Ni0.5 decreased, but still reached the level of conventional CuCr alloys. The other properties of CuCr25Ni0.5 and CuCr25W1 alloys did not degrade. (C) 2003 Elsevier B.V. All rights reserved.

关键词: CuCr25 alloys;vacuum induction melting;arc erosion rate;breakdown;strength;contact materials;electrode material;interrupters;strength;voltage