材料期刊网

Microstructure and Hardness of T250 Maraging Steel in Heat Affected Zone

MO Defeng , HU Zhengfei , CHEN Shujuan , WANG Chunxu , HE Guoqiu

钢铁研究学报(英文版)

Electronbeam (EB) welding was used in T250 maraging steel, microstructures of both base material and heat affected zone (HAZ) were investigated by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and microhardness was tested. The results showed that during EB welding, the HAZ of T250 maraging steel exhibited a continuous gradient structure. The microstructure of the entire HAZ, from fusion line, could be divided into four zones: fusion zone, overheated zone, transition zone, and hardened zone. The microhardness showed a distinct regularity in each area. The softest region was the fusion zone, whereas the hardest was the hardened zone. In the overheated zone, the hardness increased as the grain size decreased. Furthermore, in the transition zone, the hardness level dropped noticeably. The peak temperature during the thermal cycle had a great influence on the formation of reverted austenite and dissolution of the precipitated particles, which contributed a lot to the microstructure and hardness of this material.

关键词: T250 maraging steel;electronbeam weld;microstructure;microhardness

Chen系统的状态变量周期性反馈控制

李开明 , 李亚洲 , 冯维贵 , 林长

量子电子学报 doi:10.3969/j.issn.1007-5461.2007.05.014

采用非线性反馈控制,用附加了带参数的正弦项对Chen系统进行了有效的控制.随着参数k的逐渐增大,系统的动力学行为呈现出一系列的变化.数值研究结果表明:随控制参数的增大,驱动信号的强度渐大,混沌系统由混沌运动到周期轨道,最终到一相点.

关键词: 混沌 , Chen系统 , 不动点 , Lyapunov指数 , 反馈控制

SIF expressions for center cracked strip loaded by uniformly distributed stress acting on central portion of crack - Corrections of Chen's results - Response

International Journal of Fracture

关键词:

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

Fe-Mn-C系M_s及马氏体相变驱动力的热力学计算

张鸿冰 , 倪乐民 , 徐祖耀

金属学报

经 LFG(ΔG~(γ→a))-Mogutnov(ΔG_(Fe)~(γ→a))、徐祖耀(Shu-A)(ΔG~(γ→a))-Orr-Chipman(ΔG_(Fe)~(γ→a))、徐祖耀(Shu-B)(ΔG~(γ→a))-Orr-Chipman(ΔG_(Fe)~(γ→a))组合,均可算得 Fe-Mn-C 合金的 Ms 温度且与实验值十分符合.所得结果经数学处理,得 Fe-Mn-C 系 Ms 与成分的关系为:Ms(K)=817.4-7513.4xc-4141.9x_(Mn)-32083.5x_Cx_(Mn)(LFG)Ms(K)=829.9-7580.5x_C-4166.0x_(Mn)-15727.8x_Cx_(Mn)(SHU-A)Ms(K)=829.2-7276.1x_C-2915.4x_(Mn)-43825.7x_Cx_(Mn)(SHU-B)其线性相关系数均大于0.992.C 和 Mn 浓度均使合金的 Ms 线性地降低,而碳的作用几乎是Mn 的两倍.处理中引入了合金元素交互作用项(x_Cx_(Mn)),表明 C,Mn 相互加剧对 Ms 的影响。随含 C,Mn 量的增加,相变驱动力均单调地增加,而不存在奇异点.Ms 和相变驱动力的计算值均依赖于ΔG_(Fe)~(γ→a)项.

关键词:

第27卷B辑作者索引

金属学报

Volu扣ne 27SeriesB1991AUTHOR INDEX CCAO Guanghan(曹光旱)············……6一B科6CAo weijie(曹卫恋)..················……5一B32oCAO Yilin(曹益林)··················……6一B443CHANG Xin(常听)···············……1一B48CHE Guang邻n(车广灿)·············一6一B科0CHEN Erbao(陈二保)···············……6一B410CHEN Jia....

关键词:

基于二氧化碳封存的超临界两相流动的数值研究

高诚 , 胥蕊娜 , 陈黎 , 姜培学

工程热物理学报

格子Boltzmann方法(LBM)在计算复杂结构物理模型时具有独特优势并在模拟两相流动过程中能够高效清晰捕捉相界面.本文介绍了基于Shan-Chen多相模型的格子Boltzmann方法的理论成果以及基于二氧化碳封存的超临界两相流的模拟研究.结果表明,Shan-Chen模型在模拟两相流时符合Laplace定律,且两相层流时的速度分布和相渗曲线均与理论值吻合.二氧化碳封存过程中,较大的注入速率在提高二氧化碳残余俘获量的同时会降低其化学俘获量.

关键词: 二氧化碳封存 , 超临界两相流 , Shan-Chen模型

Study on the thermal stability of Cu-P based amorphous alloy systems

Journal of Materials Processing Technology

The crystallization temperatures and other thermal properties have been measured systematically for two ternary Cu-Ni-P and two quaternary Cu-Ni-Sn-P amorphous systems. The dependence of crystallization temperature on the composition for the four alloy systems can not be described basically by the usual used Naka rule. The Gibbs free energy of crystallization can be calculated for the alloy systems with the model proposed by Shu et al. Using the calculated free energy of crystallization, it is still not possible to properly describe all of the crystallization temperatures of the alloy systems. However, it has been found that the correlation between the crystallization temperature and the content of the alloy systems can be reasonably explained by the nucleation and growth rates of a new phase for the classical theory of phase transformation. It has been established that the classical theory of phase transformation can be used to describe the thermal stability of the Cu-based amorphous alloys during their crystallization process. (C) 1999 Published by Elsevier Science S.A. All rights reserved.

关键词: thermal stability;amorphous alloys;Cu-P based alloy systems;classical;theory of phase transformation;solid-liquid interface;structural model;glasses

AlInGaAs/AlGaAs应变量子阱增益特性研究

盖红星 , 李建军 , 韩军 , 邢艳辉 , 邓军 , 俞波 , 沈光地 , 陈建新

量子电子学报 doi:10.3969/j.issn.1007-5461.2005.01.016

采用Shu Lien Chuang方法计算了AlInGaAs/AlGaAs应变引起价带中重、轻空穴能量变化曲线,在Harrison模型的基础上详细地计算了AlInGaAs/AlGaAs和GaAs/AlGaAs量子阱电子、空穴子能级分布并且进一步研究了这两种材料在不同注入条件下的线性光增益.进一步计算比较可以得出AlInGaAs/AlGaAs应变量子阱光增益特性要优于GaAs/AlGaAs非应变量子阱增益特性,因此AlInGaAs/AlGaAs应变量子阱半导体材料应用于半导体激光器比传统GaAs/AlGaAs材料更具优势.

关键词: 光电子学 , 应变量子阱 , 光增益 , AlInGaAs , 半导体激光器

A molecular dynamics study of the structural change differences between Au-225 and Au-369 clusters on MgO surfaces at low temperature

Chinese Physics B

The differences in structural change between Au-225 and Au-369 clusters with their (111) facets supported on MgO(100) surfaces at 5 K are studied by using molecular-dynamics simulations with the atomic interchange potentials of the Au/MgO interface. The parameters are obtained from the ab initio energies using the Chen-Mobius inversion method. Analyses of the pair distribution functions show that the two Au clusters use different deformation processes to adjust the distances between the interface atoms, owing to the misfit between the atom distances among the clusters and the substrates. The local structural changes are identified by atomic density profiles.

关键词: interfaces;nanostructures;computer modelling and simulation;molecular;dynamics;local-structure changes;mgo(001) surface;au;adsorption;cu;nanoclusters;dimers;models;ag