材料期刊网

超塑变形中的晶粒形状效应

崔建忠 , 马龙翔

金属学报

本文讨论了在TMT处理中影响晶粒形状的因素及晶粒形状的控制方法,重点分析了晶粒形状对材料超塑变形的影响.首先讨论了轴比对超塑变形主要机制,晶界滑移速度,以及各机制对总变形贡献的影响,进而讨论了轴比对超塑变形区间转变行为的影响.提出了超塑变形的临界轴比概念.并采用Al-Zn-Mg合金对理论分析结果进行了验证.

关键词: 超塑变形 , thermomechanical treatment , grain shape

INFLUENCE OF GRAIN SHAPE AND CARBIDE ON CREEP CRACK GROWTH IN HK40

ZHU Shijie Institute of Metal Research , Academia Sinica , Shenyang , China ZHAO Jie Fushun Institute of Petrochemistry , Fushun , China WANG Fugang Dalian University of Technology , Dalian , China Institute of Metal Research , Academia Sinica , Shenyang 110015

金属学报(英文版)

The influence of two different grain shapes and carbides in the HK40 alloy,the material for use of furnace tube,on the rate of creep crack growth has been investigated.The resistance to creep crack growth of the material with columnar grains is inferior than that with equiaxial grains when the load line is perpendicular to the columnar grain axis.The influence of secon- dary carbide on the rate of creep crack propagation depends upon the Brain shape.

关键词: grain shape , null , null

电子封装用Al2O3改性环氧树脂及其性能

刘长岭 , 杨宁 , 张泽宇

应用化学 doi:10.3724/SP.J.1095.2013.30259

将不同粒径和形状的Al2O3混合颗粒填充到液态环氧树脂中,研究了单一粒径、二元混合粒径和多元混合粒径填充对固化环氧树脂复合材料的热导率、热膨胀系数和介电常数的影响.通过分形理论探讨了填料的密堆积与复合材料导热性能的关系.结果表明,单一片状及直径48μm的粒状Al2O3填充环氧树脂复合材料,具有较好的综合性能;对二元混合粒径填料,小粒子用量占填料总体积的20％～ 40％之间时,获得的复合材料的热导率、介电常数和热膨胀系数均能达到最佳值;混合粒子中粒径分布的分数维D值在某一适宜区间时,不同粒径的粒子之间可形成空隙率相对最小的紧密堆积,从而可获得热导率相对较高的复合材料.

关键词: Al2O3 , 粒径形态 , 改性环氧树脂 , 热导率 , 热膨胀系数 , 介电常数 , 分形理论

GRAIN SHAPE EFFECT IN SUPERPLASTIC DEFORMATION

CUI Jianzhong MA Longxiang Northeast University of Technology , Shenyang , China Department of Metals Forming , Northeast University of Technology , Shenyang , China

金属学报(英文版)

The method controlling grain shape in TMT processing and the effect of grain shape on char- acteristic parameters in superplastic deformation were discussed.The accommodation velocity of grahl boundary sliding,which is the dominant mechanism in superplastic deformation,and the contribution of each mechanism to the total strain,as influenced by grain shape,were ana- lyzed.Grain shape has been shown to be an essential structural factor for superplasticity.Then an analysis was made about the effect of grain shape on the region transition strain rate so that a new concept,critical aspect for superplasticity,was worked out.These predictions were compared with the measured results in an Al-Zn-Mg alloy.

关键词: superplastic deformation , null , null , null , null

强磁场对聚苯胺颗粒结构的取向性研究

功能材料

聚苯胺颗粒结构对其电学、光学性能有很大的影响.本文首次在10T强磁场的作用下用化学氧化溶液原位聚合法得到聚苯胺并观察充分聚合后聚苯胺的颗粒结构、形貌牲.强磁场作用下的原位聚合聚苯胺颗粒呈现大约50nm的棒状,而对本征态聚苯胺在强磁场下再掺杂得到20～30nm的球状颗粒,与未加强磁场作用下的礁石状颗粒有明显区别.分析认为这是由于强磁场对聚苯胺晶粒的取向作用所至.

关键词: 聚苯胺 , 强磁场 , 颗粒形貌 , 取向

晶粒形状和碳化物对HK40蠕变裂纹扩展的影响

朱世杰 , 赵杰 , 王富岗

金属学报

对两种晶粒形状的HK40炉管材料,研究了晶粒形状及碳化物对蠕变裂纹扩展速率的影响。发现当加载方向与柱状晶轴向垂直时,柱状晶材料的蠕变裂纹扩展抗力低于等轴晶材料。二次碳化物对裂纹扩展速率的影响依赖于晶粒形状。

关键词: 晶粒形状 , creep rate , rate of crack propagation , cast furnace tube