D.G. Lee
,
K.C. Jang
,
J.M. Kuk
,
I.S. Kim
金属学报(英文版)
Rotary bending fatigue tests were carried out with two kinds of materials, S43C and S50C, using the front engine and front drive shaft (FF shaft) of vehicle. The specimens were induction hardened about 1.0mm depth from the specimen surface, and the hardness value on the surface was about HRC56-60. The tested environment temperatures were -30, 25 and 80℃ in order to look over effect of the induction hardening and the environmental temperatures on the fatigue characteristics. The fatigue limit of induction hardened specimens increased more about 45% than non-hardened specimens showing that the endurances of S43C and S50C were 98.1 and 107.9MPa in non-hardened samples, 147.1 and 156.9MPa in hardened samples respectably. The maximum tensile and compressive stress on the small circular defect was about +250 and -450MPa respectively when circular defect is situated on top and bottom. The fatigue life increased 80, 25 and -30℃ in order regardless of hardening. In comparison of the fatigue lives on the basis of tested result at 25℃, the fatigue lives of non-hardened specimens decreased about 35%, but that of hardened specimens decreased about only 5% at 80℃ more than at 25℃. And fatigue life of non-hardened and hardened specimens were about 110% and 120% higher at -30℃ than that of 25℃. Based on the result of stress distribution near the defect, the tensile and compressive stress repeatedly generated by load direction were the largest on the small circular defect due to the stress concentration.
关键词:
induction hardening
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null
,
null
葛庆麟
,
施天生
,
陈廷国
,
陈源
,
吴自良
金属学报
四种不同Ti浓度的Fe-Ti合金,加氮到N/Ti>1之后,发现有两个内耗峰,并且随氮浓度之增加而同时升高。20℃处的峰是氮的Snoek峰,160℃附近的是s-i峰。s-i峰的峰高和Ti浓度成线性关系,表明起峰的反应只涉及孤立的Ti原子,与Ti-Ti原子对或杂质原子团都无关系。 提出了产生s-i峰的二种缺陷中心——Ti-N对缺陷和N-Ti-N仨缺陷——的模型(图7)。氮占Ti位就构成对缺陷,其中的Ti,N原子亲和力很强,只要合金中尚存有自由Ti原子,就不可能存有自由氮原子,因此N/Ti≤1以下,不会出现Snoek峰或s-i峰。N/Ti>1之后,多余氮原子要在对缺陷的OⅡ位和T_3位之间以约1:10的比例进行分配,直到绝大部分的对缺陷转化为仨缺陷。N/Ti(?)2以后,几乎所有的多余氮都进入了仨缺陷的OⅡ位,此时s-i峰的弛豫强度突然增加10倍。 淬火时冻结在α-Fe基体中的过饱和氮、要扩散到OⅡ位(扩散距离～10(?)),以期达到室温下的再分配,因此引起Snoek峰室温下的迅速衰减。s-i峰的形状,只取决于多余氮的浓度,与淬火温度、冷却速度无关。
关键词:
王德强
,
陈玮
,
程继健
硅酸盐通报
doi:10.3969/j.issn.1001-1625.2006.06.012
以油酸钾为熔盐,GeS2-Ga2S3-AgX(X=Cl,Br,I)玻璃为基玻璃,在270℃的环境温度下,以氮气作为保护气氛,成功地进行了K+-Ag+离子交换.在50GeS2-25Ga2S3-25AgI玻璃中,K+离子的交换深度可达256μm,并对交换深度、离子扩散系数以及离子浓度之间的规律进行了初步研究.通过离子交换研究,为制备硫卤玻璃光波导奠定了基础,并可以进一步拓宽硫卤玻璃的应用前景.
关键词:
硫卤玻璃
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离子交换
,
光波导
,
浓度分布
左鸣
,
谭舜
,
于一
,
张志涛
,
皮雳
,
张庶元
低温物理学报
高温超导体的发现动摇了支配磁通动力学二十几年的Kim-Anderson模型.于是人们提出了新的涡旋玻璃态模型,集体钉扎模型和U～j对数关系模型来描述高温超导体的磁通动力学.其中,涡旋玻璃态模型已被人们广泛接受.Fe基超导体发现后,人们它行为十分类似于高温超导体.我们实验上仔细研究了FeSe0.5Te0.5单晶的V～I关系曲线,发现上述诸模型均不能很好的解释我们的实验结果,而张的反跳模型恰能很好的拟合实验结果.本文讨论了诸模型对高温超导体磁通动力学描述的适用性并给出合理的解释.
关键词:
高温超导体
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磁通蠕动
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涡旋钉扎
Zhaojun LIN
,
Zhanguo WANG
,
Wei CHEN and Lanying LIN(Lab. of Sendconductor Materials Science
,
Institute of Semiconductors
,
Chinese Academy of Sciences
,
Beijing 100083
,
China)
材料科学技术（英文）
Samples have been prepared at different temperatures by loading I2 molecules into the cages of zeolite 5A, and the measurements of the absorption spectra have been carried out for the prepared samples. It is shown that I2 molecular clusters are formed in the cages of zeolite 5A,and it is also found that moIecuIar clusters which are bonded with intermoIecuIar forces have an important feature, namely, the intermolecular distance in molecular clusters can be changed on different preparing conditions and the blue shift of absorption edges can not be as the criterion of forming molecular clusters.
关键词:
Materials Research Innovations
Polycrystalline copper (I) oxide films were deposited on stainless steel substrate by galvanostatic electrodeposition method and were characterized by Xray diffraction and scanning electron microscopy. The effect of bath temperature, bath pH and current density on the compositon, grain size, surface texture and surface morphology of the electrodeposited films were investigated. The films deposited at low bath pH (less than or equal to 7) consisted of copper (I) oxide and metallic copper; while the films deposited at bath pH between 8 and 12 and bath temperature of 60 degrees C were pure copper (I) oxide. The preferred orientation of the copper (I) oxide films depended on the relative growth rate of (111) and (200) faces and could be controlled by adjusting the bath pH and/or the cathodic current density. (100)-oriented copper (1) oxide films could be deposited at pH=9 and current densities in the range of 0.25-1 mA/cm(2) while (111)-oriented films could be prepared at pH=12 or at pH=9 using the current densities between 1.5-2.5 mA/cm(2). Computer simulated crystallite shapes showed that the crystal shape changed from octahedral for (100)-oriented film to trucated pyramids and cubs for (111)-oriented film. And they were approved by scanning electron microscopy.
关键词:
copper(I) oxide;electrochemical deposition;thin films;microstructure;electrochemical synthesis;thin-films
Journal of Applied Physics
Dislocation distribution near the crack tip of I and II modes in bulk aluminum single crystal has been decorated by using the etching pit technique and then was observed by scanning electron microscopy. It has been shown that two kinds of distribution of dislocations, i.e., shielding and antishielding dislocations are found to exist near the crack tip. In addition to these, the dislocation-free zone is still observed to be between the crack tip and the plastic zone. According to Rice and Thomson [Philos. Mag. 29, 73 (1974)], the dislocation mode of the elastic-plastic crack is extended to include the antishielding dislocations as part of a crack-tip equilibrium configuration, which may be described as follows: (mu-b/2-pi) (S-a-e + S-s-c + S(c)s + S(e)a) [f(x')/(x - x')]dx' + sigma-a = 0, when /x/ < C, or sigma-f, when c < /x/ < s and e < /x/ < a. The factor affecting the dislocation distribution are discussed in detail.
关键词:
electron-microscope;tem observations;plastic zone;bcc metals;fracture;ductile
