材料期刊网，材料期刊，材料类期刊，材料期刊投稿

With the help of an electromagnetic stirring device and alloy melt quenching technology, the microstructure of semi-solid AZ91D magnesium alloy slurry stirred by a rotationally electromagnetic field was studied and the experimental results are shown as the following. The primary α-Mg grains are refined obviously when the slurry is stirred by a rotational electromagnetic field during continuously cooling and they are eventually changed to fine rosette grains or spherical grains. If the above semi-solid slurry is further stirred isothermally for some time, much more spherical primary α-Mg grains can be obtained. If the melt is first cooled down to a given semi-solid temperature and then starts being stirred by the rotational electromagnetic field, the primary α-Mg dendrites will be large, and a longer time will be taken and a larger stirring power will be needed for the secondary arms of the dendrites to be remelted on the roots to prepare an ideal semi-solid slurry. Theoretical analysis indicates that the strong flow motion leads to a more even temperature field and a solute field and stronger man-made temperature fluctuation in the AZ91D magnesium alloy melt so that the spherical primary α-Mg grains are increased in the slurry. Moreover, all the measures promoting the temperature fluctuation will be favorable to the formation of spherical primary α-Mg grains and all the factors increasing the arm's root remelting difficulty will be favorable to the formation of rosette-type primary α-Mg grains.

关键词: AZ91D magnesium alloy , null , null

东丽T800 H与T800 S碳纤维的微观结构比较

井敏 , 谭婷婷 , 王成国 , 冯志海 , 杨云华 , 潘月秀

材料科学与工艺 doi:10.11951/j.issn.1005-0299.20150208

东丽T800H和T800S是分别采用湿纺和干湿纺制备的两种力学性能相近的碳纤维，为弄清不同纺丝方法对T800级碳纤维微观结构的影响，采用扫描电镜、X射线衍射仪、小角X射线散射仪和高分辨透射电镜对这两种碳纤维进行测试，比较其表面形貌、断口形状和形貌、石墨微晶结构和微孔结构等．研究结果表明，湿纺制备的T800H比干喷湿纺制备的T800S的表面粗糙、断口圆度差、原纤尺寸较大、石墨微晶致密度差且发育不完善、内部微孔尺寸大、石墨微晶条带韧性差，这正是T800H的拉伸强度和断裂伸长率不如T800S的重要微观结构因素，但T800H的石墨微晶取向度不如T800S，孔隙率略高于T800S．

关键词: 碳纤维 , 微观结构 , 力学性能 , 表面形貌 , 孔结构 , 石墨微晶

T800 H碳纤维表面特性及T800 H／BA9918复合材料湿热性能研究

王迎芬 , 彭公秋 , 李国丽 , 谢富原 , 刘勇

材料科学与工艺 doi:10.11951/j.issn.1005-0299.20150420

为了研究T800H碳纤维的表面特性及其与BA9918树脂的界面匹配性，分别采用SEM、AFM、XPS和TGA对T800H碳纤维表面形貌、表面化学特性以及碳纤维上浆剂热稳定性进行表征，测试了T800H／BA9918复合材料湿热处理前后0°压缩强度、90°拉伸强度和层间剪切强度，并得到了其在湿热处理前后的开孔压缩和冲击后压缩性能。测试发现T800H碳纤维表面有明显的沟槽，有利于表面机械啮合作用；T800H／BA9918复合材料经29 J能量冲击后压缩强度为314 MPa；在130℃湿态环境下其0°压缩强度和层间剪切强度保持率高于58％，开孔压缩强度保持率高于60％。试验结果证明T800H碳纤维与BA9918树脂具有良好的界面匹配性，T800H／BA9918复合材料具有优异的耐湿热性能。

关键词: T800H碳纤维 , 复合材料 , 力学性能 , 湿热处理

T92/Super304H异种钢焊接接头的性能研究

李新梅 , 张忠文 , 邹勇 , 杜宝帅 , 邹增大

材料导报

根据新型耐热钢T92和Super304H钢的焊接特点制定了适宜的焊接工艺,研究了焊制的T92/Super304H异种钢焊接接头的力学性能.结果表明,T92/Super304H异种钢接头的各项力学性均能满足使用要求.焊缝金属的韧性远低于T92钢侧热影响区,焊缝金属的结晶形态对焊缝韧性有很大的影响.焊接接头中焊缝金属的硬度值最高,而T92钢侧热影响区硬度最低,并且不同热影响区部位显微硬度变化较大,Super304H钢侧热影响区硬度变化不大.

关键词: T92钢 , Super304H钢 , 新型耐热钢 , 异种钢 , 焊接接头

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

Friction Stir Weldabilities of AA1050-H24 and AA6061-T6 Aluminum Alloys

Huijie LIU

材料科学技术（英文）

The friction stir weldabilities of the strain-hardened AA1050-H24 and precipitate-hardened AA6061-T6 aluminum alloys were examined to reveal the effects of material properties on the friction stir welding behavior. The experimental results are obtlained. (1) For AA1050-H24, the weld can possess smoother surface ripples; there is no elliptical weld nugget in the weld; there is no discernible interface between the stir zone and the thermomechanically affected zone; and the internal defect of the weld looks like a long crack and is located in the lower part of the weld. (2) For AA6061-T6, the weld usually possesses slightly rougher surface ripples; an elliptical weld nugget clearly exists in the weld; there are discernible interfaces among the weld nugget, thermomechanically affected zone and heat affected zone; and the internal defect of the weld is similar to that of the AA1050-H24 weld. (3) The effective range of welding parameters for AA1050-H24 is narrow, while the one for AA6061-T6 is very wide. (4) The maximum tensile strength efficiency of the AA1050-H24 joints is similar to that of the AA6061-T6 joints, i.e. 79% and 77%, respectively.

关键词: Friction stir weldability , null , null , null

超音速电弧喷涂技术在440t/h CFB锅炉上的应用

尹技虎 , 闫伟

表面技术 doi:10.3969/j.issn.1001-3660.2004.06.030

目前,国内440t/h超高压再热CFB锅炉已经投运将近20余台,磨损、腐蚀等严重问题是影响锅炉稳定运行的重大因素.大量研究表明,表面涂层防磨技术是解决循环流化床锅炉高温磨蚀问题的一种较经济有效的方法.介绍了神火440t/h CFB锅炉采用超音速电弧喷涂防磨技术在某些区域增强防磨.

关键词: CFB锅炉 , 增强防磨 , 超音速电弧喷涂

240T/H型CFB锅炉炉墙的施工

王伟

耐火材料 doi:10.3969/j.issn.1001-1935.2011.04.018

调查了数百台CFB锅炉的使用情况,分析了240T/H型CFB锅炉的结构及各区域的使用环境和存在问题,结合CFB锅炉炉墙施工的多年经验,总结了240T/H型CFB锅炉各部位施工时所用的材料及施工技术要点,延长了锅炉的使用寿命.

关键词: 循环流化床锅炉 , 筑炉 , 浇注料 , 使用寿命

原油流速对T型管内H2S分布影响的数值计算

李朝阳 , 马贵阳 , 朱本光 , 乔伟彪 , 杜明俊

腐蚀与防护

在原油管输过程中，液相介质内常含有一定量以H2S为主的酸性气体，这些气体具有极强的腐蚀性，常引发管道内壁不均匀腐蚀或点蚀，从而发生泄漏事故。通过对T形管内气液两相流的研究发现，两相介质在分支处的分布总是不均匀的。利用CFD软件对T型管道内原油与H2S气液两相流动进行了数值模拟，得到了稳定状态下管道中H2S的分布规律。结果表明，原油流经T型管道时，会在支管口背流处生成稳定H2S高浓度区；原油流速越大硫化氢浓度变化越大；速度的变化对硫化氢高浓度分布区的范围影响不大。为管道腐蚀防护、确保管道安全稳定运行提供了理论依据。

关键词: T型管道 , 硫化氢 , 数值计算