Duohui BEI
,
Jianfeng GU
,
Jiansheng PAN
,
Jian Leür
,
Ke LU
材料科学技术（英文）
The behavior of gaseous nitriding on the surface nanocrystallized (SNCed) steel was investigated.The mild steel discs were SNCed on one side by using the method of ultrasonic shot peening. The opposite side of the discs maintained the original coarse-grained condition. The gaseous nitriding was subsequently carried out at three different temperatures: 460,500 and 560°C. The compound layer growth and diffusion behavior were then studied. It was revealed that SNC pretreatment greatly enhances both diffusion coefficient D and surface reaction rate. As a result, nitriding time could be reduced to the half.It was also found that the growth of compound layer with nitriding time conformed with parabolic relationship from the start of nitriding process in the SNCed samples.
关键词:
Nitriding process
,
null
,
null
Dongli SONG
,
Jianfeng GU
,
Jiansheng PAN
,
Xin YAO
材料科学技术（英文）
For large-sized AISI P20 steel block used as plastic die with a thickness of more than 200~mm, appropriate quenching processes are the key to obtain much thick hardened layer. In this paper, different quenching processes of AISI P20 steel block such as oil quenching, direct water quenching, water quenching with pre-cooling and water quenching with pre-cooling and self-tempering were numerically investigated by computer simulation based on the detailed discussion on the mathematical models of quenching processes including partial differential equations of heat transfer, thermal physical properties, latent heat, heat transfer coefficient and calculation of phase transformation, The results show that the water quenching with pre-cooling and self-tempering process can not only effectively avoid quenching cracks, but also obtain deeper harden depth than oil quenching.
关键词:
Computer simulation
,
null
,
null
,
null
陈志钢
,
唐一文
,
张丽莎
,
张新
,
贾志勇
,
余颖
材料科学与工程学报
doi:10.3969/j.issn.1673-2812.2005.04.025
以透明导电玻璃(TCO)、纳米TiO2/TCO、CNTs/TCO、铜片分别为工作电极,用简单铜盐通过阴极还原制备了Gu2O薄膜,并研究了溶液温度和衬底对电化学沉积Gu2O薄膜形貌的影响.结果表明:以TCO和铜片为衬底时,由于表面微粒为微米级,不管溶液温度高低,只能得到微米级的Cu2O薄膜;以纳米TiO2/TCO和CNTs/TCO为衬底,池温高于30℃只能得到微米级的Cu2O薄膜,而池温降到0℃时,都可得到纳米Cu2O.
关键词:
氧化亚铜
,
电沉积
,
溶液温度
,
衬底
李强
,
宣益民
工程热物理学报
建立了测量小通道扁管内纳米流体流动与对流换热性能的实验系统,测量了不同粒子体积份额的水-Gu纳米流体的管内对流换热系数和摩擦阻力系数,实验结果表明,在相同雷诺教条件下,小通道扁管内纳米流体的对流换热系数大于纯液体,且随粒子的体积份额的增加而增大,而纳米流体的阻力系教并未明显增大.
关键词:
纳米流体
,
强化传热
,
小通道扁管
董企铭
,
苏娟华
,
刘平
,
李贺军
,
康布熙
材料热处理学报
doi:10.3969/j.issn.1009-6264.2004.03.010
通过能谱和透射电镜分析研究了Gu-0.3Cr-0.15Zr-0.05Mg合金的时效析出,在4790℃时效4h形成了有序的原子排列,其化合物类型为CrCu2(ZrMg);同时存在体心的Cr相和面心的Cu4Zr相,在晶界上有少量未溶的Cr粒子.细小弥散的析出相使合金的性能得以提高,470℃时效4h～6h,硬度和导电率分别达109～108HV,79%IACS～80%IACS.
关键词:
Cu-Cr-Zr-Mg合金
,
微观组织
,
析出
,
时效性能
李增峰
,
汤慧萍
,
刘海彦
,
黄愿平
中国材料进展
doi:10.3969/j.issn.1674-3962.2006.01.006
采用机械活化制粉、低温烧结和致密化处理,制取了不同Ni含量的Mo-Gu合金.研究了Ni对Mo-Cu合金的致密性、膨胀系数、导热和导电性能的影响.结果表明,添加活化元素Ni使Mo-Cu合金的烧结致密化温度降低,热膨胀系数的变化与Al2O3陶瓷的变化很吻合,导电和导热性能降低,显微组织细小均匀,成为网络结构,是一种与Al2O3陶瓷封接匹配得很好的电子封接材料.
关键词:
Mo-Cu合金
,
活化元素
,
致密化
,
膨胀系数
,
导热系数
Y.Z. Yang
,
X.J. Bai
,
T.C. Kuang
金属学报(英文版)
The structure of bcc-Fe80 Cu2o solid solution produced by mechanical alloying of theelemental bcc-Fe and fcc-Cu powders has been studied using X-ray diffraction and theextended X-ray absorption fine structure (EXAFS) techniques. The disappearance ofelemental Fe and Cu X-ray diffraction (XRD) peaks and the presence of bcc structuralXRD peaks illustrate the formation of a nanocrystalline single-phase bcc-Fe80 Gu20solid solution. From the EXAFS results, the clear observation of Cu atoms taking onbcc coordination in the solid solution and Fe atoms remaining bcc structure furtherverifies the reality of atomic alloying between Fe and Cu atoms and the lattice changeof Cu from fcc to bcc. However, the supersaturated bcc solid solution is not chemicallyuniform, i.e., some regions are rich in Fe atoms and other regions rich in Cu atoms.
关键词:
mechanical alloying
,
null
,
null
,
null
袁志山
,
陆政
,
谢优华
,
戴圣龙
,
刘常升
航空材料学报
doi:10.3969/j.issn.1005-5053.2006.03.016
以新型高强Al-Gu-Li-X铝锂合金2A97为研究对象,通过拉伸试验研究两种三级时效工艺及其改型工艺对合金性能的影响.结果表明,含有δ′相二次析出过程的三级时效和含有δ′相回溶过程的三级时效处理合金的强度和塑性达到T6峰值时效水平,三级时效改型工艺由于增加变形使前者合金的强度升高,塑性降低,使后者的强度显著提高.三级时效和单级时效合金的主要显微组织有δ′相、θ″/θ′相和T1相.三级时效改型工艺由于增加变形促进δ′相析出和δ′相回溶,同时变形促进T1相析出,从而改变了主要强化相δ′相和T1相的数量.
关键词:
三级时效
,
铝锂合金
,
2A97
,
双级时效
,
回溶
,
RRA
,
T616
,
Al-Cu-Li-X
马洪涛
,
尹衍升
,
李静
材料科学与工艺
doi:10.3969/j.issn.1005-0299.2006.02.027
研究了Cu含量对粉末冶金Fe3Al基复合材料的烧结性能和力学性能的影响,分析了施加载荷和改变转速对加入不同量铜粉末冶金Fe3Al基复合材料的摩擦磨损性能的影响,并借助电子显微镜和能谱分析了不同铜含量Fe3Al基复合材料的磨损机理.结果表明:加入12%的Gu可使Fe3Al基复合材料具有良好的烧结性能和力学性能;载荷和转速对复合材料的磨损形式受铜的加入量的影响;铜的加入影响复合材料的磨损形式和磨损机理,当含铜量较少时,复合材料以磨粒磨损为主,随加入铜的量的增多,其磨损形式变为磨粒磨损和轻微的粘着磨损形式,加入大量铜时,则以粘着磨损为主.
关键词:
Fe3Al基复合材料
,
粉末冶金
,
磨损机理
,
磨粒磨损
,
粘着磨损
刘燕峰
,
包建文
,
李艳亮
,
益小苏
航空材料学报
doi:10.3969/j.issn.1005-5053.2011.6.012
制备了基于Cycom6070酚醛树脂的单向苎麻纤维增强复合材料,并研究了树脂、纤维及复合材料的热性能和力学性能.研究表明:将Cycom6070酚醛树脂在100℃固化1h,树脂的最低熔体黏度由0.1Pa·s变为3.6 Pa·s,适合预浸料的制备；由热失重曲线(TGA)可知:当温度升到200℃时,苎麻纤维失重约为8％；当温度升至200℃以上时,失重非常明显.经过偶联处理的苎麻纤维增强复合材料MU-62％的力学性能,均优于没有经过表面处理的纤维增强复合材料GU-62％的力学性能.电镜照片显示,纤维表面经过偶联处理后,很好地提高了复合材料中树脂和纤维界面的相容性.
关键词:
苎麻纤维
,
复合材料
,
偶联处理
