D M DIMIDUK(Wright-Laboratory
,
Materials Directorate
,
WL/MLLM
,
Wright-Patterson AFB
,
OH45433-7817
,
USA)P R SUBRAMANIAN and M G MENDIRATTA (UES
,
Inc.
,
Dayton
,
OH 45432
,
USA)
金属学报(英文版)
Since the late 1980's there have been a number of research efforts aimed at exploring and developing the refractory intermetalllic materials for service at temperatures which compete with the nickel-based superalloys in structural applications. These efforts have documented the physical and mechanical properties of a broad set of compositions. However, only in the last three years have these efforts yielded sufficient experimental results on single selected systems to suggest that damage tolerance, creep resistance and oxidation resistance may be obtained and controlled simultaneously. These findings led to alloy development concepts and approaches which are currently under investigation and are expected to lead to research focused on a smaller set of alloys. An overview of selected alloy development strategies and resulting structural properties is presented herein.
关键词:
: refractory intermetallics
,
null
,
null
张东
,
李国华
,
赵鹏
,
浦玉萍
电镀与涂饰
采用赫尔槽试验法在柠檬酸盐体系镀液中以脉冲电沉积制备Ni-Cu合金镀层.分别采用X射线衍射仪、扫描电子显微镜及能谱仪分析了不同工艺条件下所得镀层的结构、形貌及组成,探讨了镀液中铜含量(WL)和电流密度(jk)对Ni-Cu合金镀层的铜含量(WC)及性能的影响,最终获得了WC与WL、jk之间关系的经验公式.结果表明,镀层中铜含量与镀液中铜含量呈一次线性相关,与电流密度呈幂指数关系.以经验公式为指导,综合考虑镀层外观和镀液稳定性,最终得到电沉积制备Ni70Cu30合金镀层的优化工艺参数为:WL=12％,jk=0.8 A/dm2.
关键词:
镍铜合金
,
脉冲电沉积
,
电流密度
,
铜含量
,
赫尔槽试验
薛欢
,
彭文杰
物理测试
doi:10.13228/j.boyuan.issn1001-0777.20160061
对6 mm厚和8mm厚两种规格汽车大梁钢WL510以及WL590、WL700产品共4组数据进行含二维单侧容限系数的升降法分析.结果表明,参考以往经验数据的二维升降法结果的相对偏差比常规的一维升降法有大幅下降.部分情况下,二维升降法结果相对偏差仅为一维方法的1/5.另外,当试验样本量过小时,即使使用二维升降法,试验结果偏差仍较大.因此,即便使用二维升降法也得保证基本的试验样本量.从实测结果来看,该方法不但给出了很好的方差估计量,解决了传统升降法对方差估计误差较大的问题,与传统的只能利用当前试验数据的升降法相比,其可利用的信息量有了大幅度增加,所以在精度相同的情况下,可以节省大量试件;而在试件数一定的条件下,又能提高预测精度.
关键词:
汽车大梁钢
,
二维升降法
,
疲劳极限
,
相对偏差
姚丹
,
李成威
,
韩凯新
,
张武
,
陈雪婷
,
马壮
材料保护
为改进人造金刚石的表面性能,先在其上化学镀W,再化学镀Ni-P,制备了W/Ni-P包覆人造金刚石粉末.以镀液稳定性和镀层与基体结合力为评价标准,用正交试验和单因素试验优选工艺,并用扫描电镜(SEM)、能谱仪和粒度分析仪考察了优化W/Ni-P复合镀层的组织结构和镀后粉末的粒度分布.结果表明:最优化学镀W工艺为50 WL钨酸钠,32 g/L次亚磷酸钠,25 g/L柠檬酸三钠,0.002 0WL硫脲,pH值为8.5,温度为90℃,时间为1h;最优化学镀Ni-P工艺为35 g/L硫酸镍,32 g/L次亚磷酸钠,25 g/L柠檬酸三钠,0.002 0 g/L硫脲,pH值为4.5,温度为80℃,时间为1h;优化W/Ni-P层均匀细致,与金刚石结合良好,镀覆后的金刚石粉末粒度更均匀.
关键词:
人造金刚石粉末
,
W/Ni-P复合粉体
,
化学镀
,
工艺优选
,
镀层质量
Journal of Central South University of Technology
The fatigue pre-cracking 304 stainless steel (SS) specimens with lengths of 1.002 mm (L-crack) and 0.575 mm (S-crack) were prepared. Their corrosion behavior was studied by electrochemical noise (EN) in 4 mol/L NaCl + 0.01 mol/L Na(2)S(2)O(3) solution under slow-strain-rate-testing (SSRT) conditions. Moreover, the characteristics of L-crack's surface morphology and potential distribution with scanning Kelvin probe (SKP) before and after SSRT were also discussed. Compared with S-crack, L-crack is propagated and the features of crack propagation can be obtained. After propagation, the noise amplitudes increase with increasing stress and accelerating corrosion, the white noises at low and high frequencies (WL and WH) of the later stage are one order of magnitude larger than that at early stage in the current power spectral densities (PSDs). The potential PSDs also increase, but WH disappears. In addition, the crack propagation can be demonstrated according to variation of probability distribution, surface morphology and potential distribution.
关键词:
304 stainless steel;fatigue pre-cracking;electrochemical noise;stress;corrosion cracking (SCC);scanning Kelvin probe;stainless-steel;high-temperature;alloy
白井艳
,
杨科
,
李宏利
,
徐建中
工程热物理学报
本文采用正问题方法设计了适用于我国风况的风力机专用翼型族CAS-W1-XXX系列.包括最大相对厚度为15%一60%的11个不同厚度,适用于叶片根部到叶尖所有部分,设计雷诺数为3000000.设计中选择NU-MECA软件中的AUTOBLADE模块进行翼型的几何造型,使用XFOIL进行翼型的气动特性和几何特性分析.通过XFOIL对设计结果进行分析得出CAS-Wl-XXX翼型族具有良好的气动特性,前缘粗糙不敏感性以及良好的几何兼容性.
关键词:
水平轴
,
气动性能
,
最大相对厚度
雷秉强
,
朱桂森
金属学报
用金相、X射线衍射相分析和透射电镜观察等手段,细致地考察了含90和95Wt-％w的四种液相烧结W-Ni-Fe合金的微观组织.发现含90wL-％W的合金中,只要有少量的杂质碳存在,在液相烧结后缓冷的条件下将有析出相产生.经鉴定它是A_6B_6C型碳化物,其结构属于复杂立方晶系(面心立方晶格),晶格常数为1.0935nm;化学组成式可近似写成(Ni,Fe)6_W _6C;其形貌随着冷却速度大小而变化。通过各种热处理试验,找出了(Ni,Fe)6_6W_C相的形成和消除规律.
关键词:
