材料期刊网

Finite Element Analysis for Microstructure Evolution in Hot Finishing Rolling of Steel Strips

Z.D. Qu , S.H. Zhang

金属学报(英文版)

A computer model that describes the evolution of microstructures during the hot finishing rolling of SS400 steel has been proposed. It has been found that the microstructure strongly depends on processing of materials and on their parameters, which affected the history of the thermomechanical variables, such as temperature, strain, and strain rate. To investigate the microstructural evolutions during the hot finishing rolling process, the rigid-thermoviscoplastic finite element method (FEM) has been combined with dynamic recrystallization, static recrystallization, and grain growth models. The simulation results show a good agreement with those from the prediction software online.

关键词: inite element method (FEM) , null , null

PIP工艺制备2D C/SiC复合材料Z-向穿刺工艺

王其坤 , 胡海峰 , 陈朝辉 , 张玉娣 , 罗征

稀有金属材料与工程

针对2D C/SiC复合材料存在碳布层间缺乏纤维增强,层间结合较差的问题,提出通过Z-向穿刺工艺提高碳布层间结合,克服材料使用时可靠性不高的问题,并比较了穿刺工艺对复合材料微观结构和力学性能的影响.结果表明,通过Z-向穿刺工艺制得试样2D C/SiC-Z_(pin)的弯曲强度、弯曲模量和剪切强度分别为247.8 MPa、37.8 GPa和32.1 MPa,而未穿刺试样2D C/SiC的弯曲强度、弯曲模量和剪切强度分别只有219.3 MPa、34.4 GPa和23.3 MPa,由此可见,采用Z-向穿刺工艺能明显提高复合材料的力学性能.微观结构分析认为,试样力学性能提高的根本原因在于采用Z-向穿刺纤维加强了碳布层间结合,使材料具有较好的整体性,克服了复合材料层间结合较弱对力学性能带来的不利影响.

关键词: 2D , C/SiC , Z-向穿刺 , 微观结构 , 力学性能

Response to the Comment on 'Conjectures on exact solution of three-dimensional (3D) simple orthorhombic Ising lattices'

Philosophical Magazine

The error of Equation (15b) in my article [Z.D. Zhang, Phil. Mag. 87 (2007) p.5309] in the application of the Jordan-Wigner transformation does not affect the validity of the putative exact solution, since the solution is not derived directly from that equation. Other objections of Perk's comment [J.H.H. Perk, Phil. Mag. 89 (2009) p.761] are the same as those in Wu et al.'s comments [F.Y. Wu et al., Phil. Mag. 88 (2008) p.3093; p.3103], which do not stand on solid ground and which I have sought to refute in my previous response [Z.D. Zhang, Phil. Mag. 88 (2008) p.3097]. The conjectured solution can be utilized to understand critical phenomena in various systems, whereas the conjectures are open to rigorous proof.

关键词: 3D Ising model;exact solution;conjecture;critical phenomena;ferromagnetism;magnetic phase transition;model;analyticity

邯钢冷轧厂成功生产IF钢DX56D＋Z

钢铁

近日,集团邯钢公司西区冷轧厂1号镀锌线成功生产出9卷主要应用于汽车面板及高档家电外板的IF钢DX56D＋Z、共70多t,产品的屈服强度、抗拉强度、伸长率和表面质量指标均达到客户要求,为批量生产打下了坚实基础。

关键词: 批量生产 , IF钢 , 冷轧厂 , 邯钢 , 汽车面板 , 屈服强度 , 抗拉强度 , 客户要求

2D-C/SiC复合材料低温动态Z向压缩性能

叶龙海 , 邓琼 , 汤忠斌

复合材料学报

采用Hopkinson压杆试验装置,对2D-C/SiC复合材料进行了低温条件下的Z向动态压缩性能试验研究,低温条件通过控制酒精和液氮的配比系数得到,通过改变波形整形器几何尺寸的方法来实现恒应变率加载,以得到准确、可信的试验结果.试验结果表明:由于复合材料内部含有大量初始微缺陷,2D-C/SiC复合材料在低温动态加载条件下呈现伪塑性行为,其破坏时并未表现出典型的脆性破坏,而是在应力达到压缩强度时出现了显著的应变软化现象,在经历了较大的变形后才最终破坏.随着温度的降低,复合材料的动态Z向压缩强度增加,但失效应变减小.2D-C/SiC复合材料在低温环境下,其内部纤维和基体之间界面结合力增强,同时强的界面结合力可以导致高的压缩强度.

关键词: 陶瓷基复合材料 , Hopkinson压杆试验装置 , 低温 , 动态Z向压缩力学性能 , 界面强度

TC11合金热变形行为及Z-D关系的研究

孙新军 , 白秉哲 , 顾家琳 , 陈南平

稀有金属 doi:10.3969/j.issn.0258-7076.2000.03.003

考察了具有淬火马氏体组织的TC11合金在热压缩变形时的力学行为及显微组织特征. 在各个变形温度和应变速率条件下, TC11合金的应力-应变曲线均表现出先硬化后软化的趋势, 最后都获得一种相对稳定的变形状态; 与此同时, 原始非等轴片层组织通过动态再结晶转变为等轴均匀的组织; 变形温度越低或变形速率越高, 变形应力就越高, 所获得的稳态晶粒尺寸就越小; 通过对实验数据分析后发现, TC11合金在相对高低温区和相对高温区变形分别具有不同的变形激活能并由此导致Z-D关系不同.

关键词: TC11合金 , 热变形 , 力学行为 , 显微组织 , Z-D关系

Z-pins对2D编织陶瓷基复合材料搭接接头连接性能的影响

陶永强 , 矫桂琼 , 王波 , 常岩军

航空材料学报 doi:10.3969/j.issn.1005-5053.2008.06.020

对Z-pins增强2-D编织陶瓷基复合材料搭接接头在单向载荷作用下的连接性能进行了试验研究.试验结果表明Z-pins的加入能够改善2-D编织陶瓷基复合材料搭接接头的连接件能,反映在载荷-位移曲线的后半段,载荷变化出现了波动不大的起伏区域.产生此区域的原因为Z-pins从搭接接头拔出的过程中,与复合材料形成桥联,消耗了部分本该作用在开裂尖端的能量.利用有限元的方法模拟了有、无Z-pins,Z-pins在不同直径和间距下搭接接头的失效过程,并与试验结果相比较,吻合较好.

关键词: 陶瓷基复合材料 , 搭接接头 , Z-pins , 直径 , 间距

110mm厚高强度结构钢Q690D-Z35的研发

唐郑磊 , 许少普 , 崔冠军 , 杨东

钢铁研究

在生产条件下,通过成分设计和轧制、热处理工艺设计,采用晶粒细化、固溶强化、析出强化等手段,得到金相组织为保持马氏体位向的索氏体组织,生产出性能优异的Q690D-Z35高强度钢板。

关键词: 高强度结构板 , 成分设计 , 调质

采用Z-Pin增强体的3D炭/炭复合材料层间断裂行为

韩立军 , 李铁虎 , 刘建军 , 邱海鹏 , 丁海英

新型炭材料 doi:10.3969/j.issn.1007-8827.2004.02.004

采用炭纤维平纹织物和精细Z-pin制备了新型3D炭纤维预制件,炭基体采用等温化学气相沉积和高温煤沥青高压浸渍炭化制备.短梁剪切试验和开口拉剪试验用来表征Z-pin增强体对剪切破坏模式的影响.短梁剪切失效模式为假塑性,而拉剪失效模式为非假塑性破坏.分析了产生此现象的机制,短梁剪切假塑性失效由炭/炭复合材料叠层中纤维束内、纤维束间和叠层间微裂纹扩展形成,而产生拉剪失效的单一层间裂纹扩展不引起宏观假塑性现象.采用Z-pin作为提高层间剪切强度的增强体间隔1.5 mm比间隔2.5 mm可提高剪切强度40 %～50 %,该技术将成为3D炭/炭复合材料预制体制备更为先进的技术.

关键词: 层间破坏 , 3D C/C复合材料 , Z-pin , 假塑性

Three-dimensional (3D) Ising universality in magnets and critical indices at fluid-fluid phase transition

Phase Transitions

Experimental data for critical exponents in some magnetic materials are compared with recent theoretical results on the three-dimensional (3D) Ising model, as derived by one of us (ZDZ) based on two conjectures [Z.D. Zhang, Conjectures on the exact solution of three-dimensional (3D) simple orthorhombic Ising lattices, Phil. Mag. 87 (2007), pp. 5309-5419]. It is found that critical exponents in some bulk magnetic materials indeed form a 3D Ising universality. Our attention is then focused on the critical indices at fluid-fluid phase transition. We suggest to use Zhang's exponent = 3/8 to fit the experimental data over the wider asymptotic region near the critical point of a fluid-fluid phase transition. The 3D Ising universality should exist for critical indices in a certain class of magnets and at fluid-fluid phase transition.

关键词: magnetically ordered materials;fluid-fluid;phase transitions;order-disorder effects;ferromagnetic curie temperature;liquid critical phenomena;x-ray-scattering;critical exponents;critical-point;coexistence;curves;binary-solutions;ionic-solutions;behavior;equation