Hyeon-Taek Son
,
Jae-Seol Lee
,
Ik-Hyun Oh
,
Chang-Seog Kang
材料科学技术（英文）
The aims of this study are to investigate the effects of Nd addition in the Mg-Al-Ca alloys on microstructure and mechanical properties. Microstructure of as-cast Mg-5Al-3Ca alloy containing Nd consists of α-Mg matrix, eutectic phase and Al-Nd rich intermetallic compound. As Nd addition was increased, α-Mg matrix morphology was changed from dendritic to equiaxed grains and average value of grain size was decreased. Nd addition to Mg-5Al-3Ca based alloys resulted in the formation of Al-Nd rich intermetallic compounds at grain boundary and α-Mg matrix grains. And these Al-Nd rich intermetallic compounds were dispersed homogeneously. In these alloys, two kinds of eutectic phases were observed, i.e. coarse irregular-shape structure at grain boundary and fine needle-shape structure in the α-Mg matrix grain. It is found that the ultimate strength showed the maximum value of 271 MPa at Mg-5Al-3Ca-2Nd alloy and elongation was decreased as the addition of Nd was increased.
关键词:
Mg-Al-Ca alloy
,
null
,
null
林青
,
谢欣云
,
朱鸣
,
张苗
,
林成鲁
功能材料与器件学报
doi:10.3969/j.issn.1007-4252.2002.02.024
阐述了自加热效应产生的原因以及它对SOI电路的影响,并介绍了为克服自加热效应和满足某些特殊器件和电路的要求,国内外正在竞相探索研究的新型SOI结构,如SOIM、SilicononAlN、GPSOI、SiCOI、GeSiOI、SON、SSOI等.结合SOI新结构制备工作,报道了SOI的自加热效应及其新结构的研究进展.
关键词:
自加热效应
,
沟道电流
,
跨导畸变
,
负微分迁移率
,
SOI新结构
李海军
,
徐建忠
,
龚殿尧
,
王国栋
,
刘相华
钢铁
将源于BP人工神经网络改进策略的动量项技术引入到带钢热连轧负荷分配中来,提出了误差补偿迭代算法,介绍了该算法的推导过程,并对算法的合理性进行了分析.基于误差补偿迭代算法及传统的Newton-Raph-son法,开发了带钢热连轧精轧过程设定系统软件.离线模拟计算结果表明,与Newton-Raphson法相比,误差补偿迭代算法对初始厚度分布的要求比较宽松,有利于新产品的开发,具有良好的在线应用前景.
关键词:
负荷分配
,
计算机过程控制
,
动量项
,
带钢热连轧机
,
误差补偿迭代算法
廖慧敏
,
龙思远
,
蔡军
材料科学与工艺
本文通过静态拉伸试验机和高应变速率冲击拉伸试验装置,对AZ91D压铸镁合金分别进行了不同应交率下(10~(-4)、10~(-2)、300和1 400 s~(-1))拉伸力学性能的试验,获得了各应变速率下完整的应力-应变曲线.并通过扫描电镜对其拉伸断口进行分析.试验结果表明,其屈服应力(σ_s)、拉伸强度(σ_b)随着应变速率的增加而增加,失稳应变(ε_b)则随着应变速率的增加而有所减小;而弹性模量则对应变率不敏感.采用John-son-Cook材料模型描述AZ91D镁合金应变速率相关的应力应变本构模型,其拟合结果和实验结果基本相吻合.扫描电镜断口分析结果表明,动态和静态的断裂方式基本相同,都是以准解理断裂特征为主,局部区域伴有解理断裂;存在典型的缩松断裂形貌.
关键词:
应变速率AZ91D镁合金
,
力学行为
