Jie Chen
,
Chong-Gao Bao
,
Yong Wang
,
Jin-Ling Liu
,
Challapalli Suryanarayana
金属学报(英文版)
doi:10.1007/s40195-015-0333-6
Magnesium matrix composites reinforced with AlN particles were fabricated by the powder metallurgy technique. The evolution of lattice constants and solid solubility levels of Al in α-Mg and the microstructure of Mg-Al/AlN composites were investigated in the present study. The results showed that the solid solubility of Al in α-Mg reached a relatively high level by the P/M process with a long time of milling. X-ray diffraction showed that the peaks of Mg phase clearly shifted to higher angles. The lattice constants and cell volume decreased significantly compared with those of standard Mg due to a significant amount of Al incorporated into α-Mg in the form of substitutional solid solution. The degree of lattice deformation decreased at a low sintering temperature and increased at higher sintering temperatures due to the presence of AlN. Microstructural characterization of the composites revealed a necklace distribution of AlN particles in the Mg matrix. Heat treatment led to precipitation of Mg17Al12 from the supersaturated α-Mg solid solution. The precipitate exhibited granular and lath-shaped morphologies in Mg matrix and flocculent precipitation around AlN particles.
关键词:
Metal matrix composite
,
AlN particle
,
Microstructure
,
Lattice parameter
,
Powder metallurgy
,
Solid solubility
MAO Weimin University of Science and Technology
,
Beijing
,
100083
,
China.
材料科学技术（英）
The recrystallization texture in commercially pure Al is investigated after the samples are rolled differently and annealed.The samples with low rol- ling reductions could be generally recovered or recrystallized in situ and characterized by the re- tained G{110}<001>component.This recovery process decreases during annealing with the increase of reduction.The appearance of the B/R{359}. <132>and R{123}<634>components de- pending on the rolling reduction is investigated and the less developed Cube{100}<001>component in commercially pure ahninium is also discussed.
关键词:
recrystallization
,
null
,
null
,
null
Journal of Applied Physics
Based on the developed multiple-scattering theory [C.-W. Nan and F. S. Jin, Phys. Rev. B 48, 8578 (1993)], an effective-medium theory (EMT) is proposed to treat coupled electromechanical behavior in composite media. The explicit relations for determining effective behavior of piezoelectric composites are derived. To illustrate the technique, numerical results of piezoelectric ceramic/epoxy composites for various particle shapes are presented over the whole range of concentrations. The EMT estimates are shown to be in good agreement with available experimental results. Porous piezoelectric ceramics are also discussed. The EMT predicts a similar critical behavior for heterogeneous piezoelectric materials to recent experiments.
关键词:
electromechanical properties;ceramics
Ruwei GAO
,
Wei CHEN
,
Jiancheng ZHANG
,
Weicun FONG
,
Wei LI
,
Xiumei LI
材料科学技术（英）
For both sintered and nanocomposite NdFeB magnets, deltaM(H) of the Henkel plot increases from zero, and reaches a peak, then decreases and changes to the negative values with increasing applied field. This shows that the intergrain interaction changes from the exchange-coup ling type into the magnetostatic interaction type. The magnetic field corresponding to the peak of deltaM(H) is slightly smaller than the coercivity of magnet. The peak of deltaM(H) for aligned sintered magnet is greater than that for misaligned magnet. deltaM(H) peak of the nanocomposite NdFeB magnets increases with decreasing grain sizes. It indicates that the effect of alignment field on the properties of magnet is similar to that of exchange-coupling interaction.
关键词:
TAO Zengyi LUO Jiaming Huazhong University of Science and Technology
,
Wuhan
,
China TAO Zengyi
,
Faculty of Metallic Materials
,
Dept.of Mechanical Engineering No.2
,
Huazhong University of Science and Technology
,
Wuhan 430074
,
China
金属学报(英文版)
The influence of laser surface melting and induction hardening on the surface structure,con- tact fatigue life and failure behaviour of the nodular cast iron has been investigated.The con- tact fatigue life can be improved by both laser treatment and induction hardening,but the fail- ure process and type are different from each other.The former is due to lumpy and deep spal- ling caused by crack propagation between the quenching zone and the substrate,and the latter is due to nubby and surface flaking caused by the oil wedged action into surface cracks.
关键词:
surface hardening
,
null
,
null
,
null
徐卫兵
,
戈明亮
,
何平笙
应用化学
doi:10.3969/j.issn.1000-0518.2001.09.011
用熔融插层法制备聚甲醛/蒙脱土纳米复合材料,用X射线衍射研究聚甲醛及复合材料的微观结构,表明复合材料是纳米复合材料.用DSC法研究其非等温结晶行为,对所得数据分别用Jeziorny法、Ozawa法和Liu法进行处理.结果表明,Jeziorny法和Liu法处理非等温结晶过程比较理想.聚甲醛及聚甲醛/有机蒙脱土纳米复合材料的结晶活化能分别为334.6和196.9 kJ/mol,说明有机蒙脱土的加入,降低了聚甲醛的结晶活化能,且t1/z缩短,起到了异相成核的作用.
关键词:
聚甲醛
,
蒙脱土
,
纳米复合材料
,
非等温结晶动力学
王平华
,
徐国永
应用化学
doi:10.3969/j.issn.1000-0518.2004.08.007
用熔融复合法制备聚丙烯/凹凸棒土纳米复合材料,用DSC法研究其非等温结晶行为,对所得的数据分别用Jeziorny法、Ozawa法和Liu法进行处理.结果表明,Jeziorny法和Liu法处理非等温结晶过程比较理想.聚丙烯及聚丙烯/凹凸棒土纳米复合材料的结晶活化能分别为194.1和162.8 kJ/mol,表明凹凸棒土的加入,降低了聚丙烯的结晶活化能,且t1/2缩短,起到了异相成核作用.
关键词:
聚丙烯
,
凹凸棒土
,
纳米复合材料
,
非等温结晶动力学
Scripta Materialia
A recent comment on a previously published paper addressed the invalid explanation of the off diagonal interdiflusion coefficients of the beta-Ni(Al,Cr) phase in the Ni-Cr-Al system according to the symmetric property of the thermodynamic matrix. In this paper, the experimental data presented by Hou et al. was reanalyzed and the interdiffusion coefficient matrix was estimated again. The results of the analysis have been discussed in terms of a brief reply to the comments of Liu and Liang. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
关键词:
Diffusion;Intermetallic compound;Ni-Cr-Al
