K.Raghuk
,
an
,
K.Hokamoto
,
J.S.Lee
,
A.Chiba
,
B.C.Pai
材料科学技术（英文）
Metal matrix composites (MMCs) offer extra strength and high temperature capabilities in comparison with unreinforced metals. Aluminum composites possess higher stiffness, strength, fatigue properties and low weight advantages. Carbon fiber reinforced Al composites (Al-Cf) and silicon carbide particulate reinforced Al composites (Al-SiCp) were shock densified using axisymmetric assemblies for underwater explosions. Unidirectional planar shock waves were applied to obtain uniform consolidation of the composites. The energy generator was a high explosive of 6.9 km/s detonation velocity. Irregular morphological powders of Al were the base material. The reinforcement ratio was 15 Vol. pct for Al-Cf composites and 30 Vol. pct for Al-SiCp composites. The microstructural and the strength characteristics of the shock consolidated Al composites are reported.
关键词:
Shock consolidation
,
null
,
null
,
null
R.Karthikeyan
,
S.Raju
,
R.S.Naagarazan
,
B.C.Pai
材料科学技术（英文）
In the present study an effort has been made to optimize the machining conditions for electric discharge machining of LM25 Al (7 Si, 0.33 Mg, 0.3 Mn, 0.5 Fe, 0.1 Cu, 0.1 Ni,.2 Ti) reinforced with green bonded SiC particles with approximate size of 25 mum. Polynomial models were developed for the various EDM characteristics such as metal removal rate, tool wear rate and surface roughness in terms of the process parameters such as volume fraction of SK, current and pulse time. The models were used to optimize the EDM characteristics using nonlinear goal programming.
关键词:
R.Karthikeyan
,
R.Adalarasan
,
B.C.Pai
材料科学技术（英文）
The present work is focused on optimization of machining characteristics of Al/SiCp composites. The machining characteristics such as specific energy, tool wear and surface roughness were studied. The parameters such as volume fraction of SiC, cutting speed and feed rate were considered. Artificial neural networks (ANN) were used to train and simulate the experimental data. Genetic algorithms (GA) was interfaced with ANN to optimize the machining conditions for the desired machining characteristics. Validation of optimized results was also performed by confirmation experiments.
关键词:
Al/SiCp composites
,
null
,
null
Journal of Alloys and Compounds
Nd-Fe-(B.C) alloys have been synthesized by mechanical alloying and subsequent heat-treatment, with B4C as one of the starting materials. It is found that when the pure B4C is milled alone, it proves difficult to decompose. When the B4C compound is milled with Nd and Fe, the complete decomposition of B4C and the formation of Nd2Fe14(B,C) phase is observed. Furthermore, the competition between B and C atoms for entering the Nd2Fe14B lattice. the effects of the B4C content on the structure and the magnetic properties of Nd2Fe14(B,C)-based alloys are investigated. A coercivity as high as 18.3 kOe and the maximum energy product of 10.4 MGOe have been achieved for the Nd-Fe-(B,C) alloys. (c) 2005 Elsevier B.V. All rights reserved.
关键词:
permanent magnets;mechanical alloying;fe-c alloys;permanent-magnets;r2fe14c;nd
刘建功
,
殷小玮
,
成来飞
,
张立同
,
王琴
复合材料学报
为了降低液硅渗透法制备C／C—SiC复合材料中残留Si的含量，采用浆料浸渗结合液硅渗透工艺制备B12（C，Si，B）3改性C／C—SiC复合材料。通过分析不同比例B4C—Si体系在不同温度的反应产物，确定了B12（C，Si，B）3的生成条件。结果表明：B4C和Si在1300℃开始反应，生成少量B12（C，Si，B）3和SiC，且B12（C，Si，B）3的生成量随反应温度的升高而增加；当B4C和Si的摩尔比为3：1、反应温度为1500℃时，产物为B12（C，Si，B）3和SiC液硅渗透法制备的C／C—SiC复合材料相组成为非晶态C、β-SiC和B12（C，Si，B）3，未见残留Si。
关键词:
复合材料
,
C
,
C—SiC
,
B12(C，Si，B)3
,
浆料浸渗
,
液硅渗透
Physics Letters A
The magnetic properties of the mixed ferro-ferrimagnetic compounds with (A(a)B(b)C(c))(y)D, in which A, B, C and D are four different magnetic ions and form four different sublattices, are studied by using the Ising model. And the Ising model was dealt with standard mean-field approximation. The regions of concentration in which two compensation points or one compensation point exit are given in c-a, b-c and a-b planes. The phase diagrams of the transition temperature T-c and compensation temperature T-comp are obtained. The temperature dependences of the magnetization are also investigated. Some of the result can be used to explain the experimental work of the molecule-based ferro-ferrimagnet ((NiaMnbFecII)-Mn-II-Fe-II)(1.5) [Cr-III (CN)6] - zH(2)O. (C) 2003 Elsevier B.V. All rights reserved.
关键词:
mixed ferro-ferrimagnet;Ising model;four sublattices;phase diagram;transition temperature;compensation temperature;magnetic-properties;prussian blue;alloy
Journal of Alloys and Compounds
A model for diffusion is applied to the Ni-Al system to optimize the mobility parameters for the 132-b.c.c. phase by fitting the experimentally obtained diffusivities. In the model, the activation energy for diffusion is expressed as a function of the degree of ordering which is evaluated from thermodynamic data. The diffusivities, from the model are used to simulate diffusion experiments. The results are compared with experimental data and it is concluded that the model can yield satisfactory prediction. (C) 2007 Elsevier B.V. All rights reserved.
关键词:
intermetallics;diffusion;thermodynamic modeling;alloys;fe;interdiffusion;model
