共查询到20条相似文献,搜索用时 62 毫秒
1.
采用多靶磁控溅射制备了W/SiC纳米多层膜,并用XRD和TEM研究了W/SiC纳米多层膜的微结构。研究表明,W/SiC纳米多层膜的调制结构界面平直,清晰,周期性好,SiC调制层为非晶态,W调制层在大调制周期为纳米晶,并随调制周期减小逐渐转变为非晶态。 相似文献
2.
磁控溅射SiC/W纳米多层膜的微结构研究 总被引:2,自引:0,他引:2
用磁控溅射法在Si基底上制备了不同调制波长的SiC/W纳米多层膜。利用小角度X射线衍射技术,详细研究了其中典型的多层膜的调制周期性。各子层的厚度及界面平整度等界面微观结构。结果表明:磁控溅射法制备的纳米多层膜具有较好的周期结构及陡峭的界面梯度,由衍射峰位置计算出的界面不均匀旗与子层厚度之比一般在5%以内。 相似文献
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TiN/AlN纳米多层膜的研究 总被引:8,自引:0,他引:8
采用反应溅射法制备了TiN/AlN纳米多层膜,并通过XRD,HREM和显微硬度计对多层膜的调制结构和力学性能进行了研究。结果表明:TiN/AlN纳米多层膜有较好的调制结构。小调制周期时,AlN调制层以FCC结构在TiN调制层上外延生长。调制周期增大,AlN调制层中出现六方晶型。TiN/AlN的显微硬度随调制周期的减小单调上升,并在调制周期^=2nm时达到最高值HK3293。硬度的增高极有可能是小调 相似文献
4.
用磁控射法制备Mo/Si多层膜和Mo/B4C多层膜,并在真这中加热30min,温度为200,400,600,800和1000℃。用小角X射线衍射法和透射电镜研究不同温度下加热的样品。实验结果表明,当加热温度达600℃时,Mo/Si多层膜周期被破坏。 相似文献
5.
c-AlN的生长对AlN/(Ti,Al)N纳米多层膜力学性能的影响 总被引:4,自引:0,他引:4
采用反应磁控溅射制备了具有不同调制周期的AlN/(Ti,Al)N纳米多层膜,研究了亚稳相立方氮化铝(c—AlN)在纳米多层膜中的生长条件及其对薄膜力学性能的影响.结果表明:在小调制周期下AlN以立方结构存在,并与(Ti,Al)N层形成同结构共格外延生长,使纳米多层膜产生较大的品格暗变.与此相应,AlN/(Ti,Al)N纳米多层膜硬度和弹性模量随调制周期的减小呈单调上升的趋势,当调制周期小于8~10nm时其增速明显增大,并在调制周期为1.3nm时达到最高硬度29.0GPa和最高弹性模量383GPa,AlN/(Ti,Al)N纳米多层膜的硬度和弹性模量在小调制周期时的升高与亚稳相c—AlN的产生并和(Ti,Al)N形成共格结构有关。 相似文献
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采用一种新型的离子束辅助非平衡反应磁控溅射设备制备了TiN/AlN纳米多层复合膜。采用XRD衍射、TEM、显微硬度计和干涉显微镜对TiN/AlN纳米多层膜的微结构和力学性能进行了表征。结果表明:TiN/AlN多层膜有良好的周期;调制结构影响薄膜的择优取向,薄膜整体表现出硬度增强的效果,硬度随调制周期的变化而变化并在调制周期为7、5nm时达到最大值。 相似文献
8.
对多靶离子溅射制备的Nb/Si周期多层膜的微结构进行了实验研究。利用X射线衍射和截面透射电子显微镜观测到室温和560℃沉积的Nb/Si多层膜为非晶多层膜,但它们的微结构有很大的不同。采用沉积原子表面活动性和界面反应程度解释了所得到的结果。 相似文献
9.
使用多弧离子镀技术在高速钢基体上制备了调制周期为5~40 nm的Ti/TiN纳米多层膜,用扫描电子显微镜(SEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)、纳米压痕仪和划痕仪等手段表征薄膜的微观结构和性能,研究了调制周期对Ti/TiN纳米多层膜性能的影响,并讨论了在小调制周期条件下Ti/TiN纳米多层膜的超硬效应和多弧离子镀技术对纳米多层膜硬度的强化作用。结果表明,与单层TiN相比,本文制备的Ti/TiN纳米多层膜分层情况良好,薄膜均匀致密,没有明显的柱状晶结构,TiN以面心立方结构沿(111)方向择优生长。随着调制周期的减小薄膜的硬度呈现先增大后减小的趋势,并在调制周期为7.5 nm时具有最大的硬度42.9 GPa和H/E值。这表明,Ti/TiN在具有最大硬度的同时仍然具有良好的耐磨性和韧性。Ti/TiN纳米多层膜的附着力均比单层TiN薄膜的附着力高,调制周期为7.5 nm时多层膜的附着力为(58±0.9) N。 相似文献
10.
采用X射线衍射分析表征了磁控溅射方法制备的Co/Si周期多层膜,由带折射修正的布喇格衍射定律导出多层膜周期厚度,对两组折射修正公式的计算结果进行对比,讨论了平均折射率修正值为负的原因,并应用薄膜光学理论分析小角X射线衍射谱中出现的一系列现象。 相似文献
11.
《International journal for numerical methods in engineering》2018,113(9):1488-1506
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method. 相似文献
12.
Standards are the basis for production enterprises to organize production ex-factory inspection trade 《中国标准化(英文版)》2008,25(1):24-25
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.…… 相似文献
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A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa. 相似文献
15.
Steffen Müller-Probandt 《材料科学与工程:中英文B版...》2018,(4):161-177
We associate a variety of innovations with the term "Industry 4.0". The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di... 相似文献
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On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.…… 相似文献
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Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß. 相似文献
18.
Janet Lang 《Materials and Manufacturing Processes》2017,32(7-8):857-866
ABSTRACTThe production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them. 相似文献
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C. Qihong W. Zhan‐Wen J. Yi J. Yehua L. Fei F. Hanguang 《Materialwissenschaft und Werkstofftechnik》2014,45(7):582-590
In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill. 相似文献
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Dimiter Hadjistamov 《材料科学与工程:中英文B版...》2019,(2):56-65
The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ... 相似文献