L. W Zhang
,
R.S. Wang
,
J. Th.M.De Hosson
,
Y.L. Xia and F. G. Wang 1) The State Key Lab. for Materials Modification by Laser
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Ion and Electron Beams
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Dalian University of Technology
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Dalian 116023
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China 2) Department of Applied Physics
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University of Groningen
,
The Netherlands
金属学报(英文版)
A three-dimensional transient heat transfer model for laser transformation hardening process has been developed in this paper. The finite size of the laser treated sample, the surface heat loss of the sample, the latent heat of phase transformation and the temperature dependence of thermal properties of materials were considered. The heat source was considered as a moving Gaussian heat flux with a constant velocity. Three-dimension unequally spatial grid explicit finite difference equations, alternating direction implicit finite difference equations and implicit finite difference equations were deduced respectively. Three programs to calculate the temperature field were developed using Fortran language. The transient temperature fields of C22, 42CrMo, C60 steel samples during laser transformation hardening process were calculated using these programs, and the widths and depths of laser transformation hardening zones were also predicted. C22, 42CrMo, C60 steel samples were treated by CO_2 laser,the widths and depths of laser transformation hardening zones of these samples were also measured experimentally. The calculated widths and depths of laser transformation hardening zones are in good agreement with the experimental results.
关键词:
temperature field
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null
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null
L. W. Zhang
,
J. Th.M.De Hosson
,
Y.L. Xia and F. G. Wang 1)The State Key Lab. for Materials Modification by Laser
,
Ion and Beams
,
Dalian University of Technology
,
Dalian 116023
,
China 2)Department of Applied Physics
,
University of Froningen
,
The Netherlands
金属学报(英文版)
In this paper,a thermal elastic-plastic 2-D finite element model of stress generation during laser transformation hardening process was developed. In this model, the mechanical properties of the material, Young's modules E, Poisson's ratio v, yield limit s, and thermal expansion coefficient α, are all change with temperature. The equivalent expansion method was used to deal with the problem with phase transformation. Based on this model, a program to calculate the residual stress field was developed using FORTRAN language. The residual stress fields in CO2 laser transformation hardened MoCu nodular iron were calculated. The calculated results showed that in the transformation hardened zone, the residual stress state is compress,whereas adjacent to this zone the residual stress state is tensile, and there is a tensile stress peak close to the transformation hardened zone. To verify this model, the residual stress fields were measured using X-ray diffraction method. The calculated results of residual stress fields are in good agreement with the experimental results.
关键词:
laser
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null
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null
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null
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null
孙银洁
,
胡胜泊
,
李秀涛
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2010.02.027
利用SEM、TEM、XPS、XRD、Raman和元素分析仪分析了M40J和T300的表面化学、物理及微观结构特征.研究发现:M40J含碳量高于T300纤维,而含氮量低于T300纤维,且表面活性基团比T300纤维低;M40J和T300碳纤维表面具有大量沟槽,前者相对长而浅,后者相对短而深;T300纤维端面皮芯结构明显,而M40J端面结构较均匀;M40J的微晶结构及取向性优于T300碳纤维.
关键词:
M40J碳纤维
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微观结构
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化学特征
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物理特征
韩建平
,
秦滢杰
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高伟
,
刘新东
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2014.05.010
针对卫星构件的不同需求,开发了一种芳香胺固化的环氧树脂BA204.研究了无溶剂及溶剂法成型的M40J/BA204复合材料力学、真空放气性能和管件在模拟温度交变条件下的性能变化情况.结果表明:两种方法制备的复合材料力学性能均能满足卫星构件要求,无溶剂法制备的复合材料力学性能优于溶剂法.采用无溶剂法制备的M40J/BA204复合材料其真空质损率为0.23％,可收集挥发性凝聚物为0.009％;复合材料管件经200次热循环冲击后力学性能变化不大,表明M40J/BA204复合材料具有良好的热稳定性.
关键词:
卫星构件
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M40J/BA204复合材料
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纤维缠绕
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无溶剂法
惠雪梅
,
王晓洁
,
尤丽虹
,
王益
,
全小平
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2006.z1.011
通过地面环境模拟实验,分析了高模碳纤维/环氧树脂改性氰酸酯复合材料(M40J/CE/EP)的表面元素,研究了高真空加热环境下复合材料的真空出气性能和出气气体成分.结果表明,M40J/CE/EP复合材料的表面主要由C、O、N元素构成;经高真空加热后,复合材料的出气气体成分以小分子挥发物和碳氢化合物电离碎片为主,有可能在空间低温条件下冷凝在航天器的敏感器件表面而造成污染;通过真空出气性能实验测得,M40J/CE/EP复合材料的总质量损失(TML)的平均值为0.27%,收集到的可凝挥发物(CVCM)为0,完全达到出气筛选合格的指标要求.
关键词:
氰酸酯树脂
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复合材料
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出气
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X射线光电子能谱
Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy
The spin-Hamiltonian parameters (g factors g(parallel to), g(perpendicular to), and zero-field splittings b(2)(0), b(4)(0), b(4)(4), b(6)(0), b(6)(4)) for 4f(7) ion Gd(3+) at the tetragonal M(4+) site of zircon-structure silicates MSiO(4) =Zr, Hf, Th) are calculated from a diagonalization (of energy matrix) method. The Hamiltonian concerning this energy matrix contains the free-ion, crystal-field interaction and Zeeman interaction terms and the 56 x 56 energy matrix is constructed by considering the ground multiplet (8)S(7/2) and the excited multiplets (6)L(7/2) (L = P, D. F. G, H, I). The defect structures of Gd(3+) centers in the three MSiO(4) crystals are yielded from the calculation. The results are discussed. (C) 2011 Elsevier B.V. All rights reserved.
关键词:
Electron paramagnetic resonance (EPR);Crystal-field theory;Diagonalization method;Gd(3+);MSiO(4) (M = Zr Hf Th);superposition-model analysis;electron-paramagnetic-resonance;single-crystals;epr-spectra;zrsio4;field;absorption;gadolinium;growth;garnet
宁波
,
赵宇
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李波
钢铁研究学报
磁温补偿合金1J30经深低温处理后合金中的部分奥氏体转变为马氏体,致使合金的磁温补偿能力下降.通过调整镍含量,同时添加铬,得到了新型磁温补偿合金1J30M.这种新型磁温补偿合金既具有1J30合金的磁温补偿能力,又具有1J32合金的耐深低温能力.
关键词:
磁温补偿合金
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深低温
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马氏体相变
高禹
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杨德庄
,
何世禹
材料研究学报
doi:10.3321/j.issn:1005-3093.2004.05.013
分别测量了经不同次数单向真空热循环试验(93～413 K,10-5Pa)后M40J/5228A复合材料的拉伸强度、弯曲强度和层剪强度,研究了真空热循环对M40J/环氧复合材料力学性能的影响.结果表明,随着真空热循环次数的增加,90°和0°拉伸强度下降,并分别于48次和40次真空热循环后趋于平缓.弯曲强度随着真空热循环次数的增加表现出先上升后下降再趋于平缓的特征,而层剪强度变化不大.90°和0°拉伸强度的变化与界面脱粘程度密切相关.弯曲强度变化主要反映真空热循环时树脂基体后续固化效应的影响.层剪强度变化是界面脱粘与树脂基体后续固化两种因素综合作用的结果.
关键词:
复合材料
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碳/环氧复合材料
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真空热循环
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力学性能
,
断口
