SiC 颗粒、C_f 纤维增强 Al 基复合材料扫描电镜观察

使用Ｓ－３６０型高分辩扫描电镜及Ｘ－射线能谱仪、波谱仪对ＳｉＣ颗粒、Ｃｆ纤维增强Ａｌ基复合材料的断口及合金结构进行了观察，对其中纤维排列与分布，界面元素的测定，纤维与基体结合的状况进行了分析，提出了在扫描电镜上定量计算Ａｌ基复合材料中纤维面积百分比含量的方法。     

SiC颗粒,Cf纤维增强Al基复合材料扫描电镜观察

使用Ｓ－３６０型高分辨扫描电镜及Ｘ－射线能谱仪、波谱仪对ＳｉＣ颗粒、Ｃｆ纤维增强Ａｌ基复合材料的断口及合金结构进行了观察，对其中纤维排列与分布，界面元素的测定，界面元素的测定，纤维与基体结合的状况进行了分析，提出了在扫描电镜上定量计算Ａｌ基复合材料中纤维面积百分比含量的方法。     

切削刀具的新型PVD涂层

切削刀具的ＰＶＤ工艺比ＣＶＤ工艺有一定的优越性，但目前ＰＶＣＤ工艺的主要涂层－ＴｉＮ已经不能满足加工各种新材料的要求。本文介绍美国Ｋｅｎｎａｍｅｔａｌ Ｂａｒｌｚｅｒｓ，Ｍｕｌｔｉ－Ａｒｃ和Ｎｏｒｔｏｎ－Ｄｉａｍｏｎｄ等公司利用ＰＶＤ工艺开发ＴｉＣＮ，ＴｉＡＩＮ，金刚石，ＣｒＣ，ＣｒＮ，ＺｒＮ等新涂层的进展情况。     

Y—TZP增韧Al2O3—TiC陶瓷复合材料的研究

热压烧结制备了Ａｌ２Ｏ３／ＴｉＣ／Ｙ－ＴＺＰ陶瓷复合材料，研究了Ｙ－ＴＺＰ含量对该材料的组织结构、力学性能和耐磨性能的影响。随Ｙ－ＴＺＰ含量增加，复合材料的耐磨性提高，弯曲强度σｆ和断裂韧性ＫＩＣ均比Ａｌ２Ｏ－ＴｉＣ提高１倍，分别达到１０５４ＭＰａ和１１．６５ＭＰａ·ｍ＾１／２。试验结果表明，Ａｌ２Ｏ３／ＴｉＣ／Ｙ－ＴＺＰ复合材料的强韧化机理主要为Ｙ－ＴＺＰ的应力诱发ＺｒＯ２相应增韧、裂纹偏转和晶     

碳、钛对铸造Fe－Cr－Al耐热钢性能的影响

Ｆｅ－Ｃｒ－Ａｌ耐热铸钢因晶粒易粗大导致强度塑性较差而限制了使用，通过强化精炼、合金化处理及改进铸造工艺能防止这种倾向。研究了碳、钛含量对该耐热铸钢室温强度、高温强度及抗氧化性能的影响，试验结果表明，当Ｃ＜０．２０％、Ｔｉ＜１．０％时，铸造Ｆｅ－Ｃｒ－Ａｌ耐热钢有较好的综合性能。     

C／Cu复合材料在电刷中的应用

介绍了我国独创的由镀Ｃｕ碳纤维与改性后的石墨复合而成的一种非均质结构复合材料电刷－Ｃ／Ｃｕ复合材料电刷。经过实践应用表明这种新型复合材料电刷具有载流密度大，换向性能优良，滑动接触性能好及性能可设计等优良的综合性能，是一种新型的电刷材料。     

热处理对Cu－Al－Be－Cr形状记忆合金性能和结构的影响

本文研究了不同热处理工艺对Ｃｕ－Ａ１－Ｂｅ－Ｃｒ形状记忆合金的马氏体逆转变以及形状记忆效应的影响，并通过正电子湮没Ｄｏｐｐｌｅｒ增宽线性参数的测量及金相组织和相结构分析，探讨了组织结构与记忆效应间的内在联系。结果表明，分级淬火下的合金具有最好的记忆性能，直接淬火性能最差。     

纤维强化金属基复合材料及其应用

纤维强化金属基复合材料由于具备各种特殊性能或优良综合性能，越来越受到人们的重视。讨论了纤维强化金属基复合材料主要组成部分－作为增强剂的纤维，以及复合材料的制造工艺，并列举了若干典型碳纤维增强金属基复合材料的应用实例。     

Al—Si复合材料内在组分对润滑磨损性能的影响

本文研究了硅酸铝纤维增强Ａｌ－Ｓｉ复合金复合材料在润滑状态下磨损性能,结果表明,Ａｌ－Ｓｉ复合材料的耐磨性优于基体合金,随纤维体积分数增加,复合材料耐磨性增加。基体合金Ｓｉ含量对复合材料耐磨性没有明显影响Ａｌ－Ｓｉ合金中加入Ｍｇ元素,可显著提高其复合材料的耐磨性。     

CVD SiC涂层的致密化工艺研究

研究了复合材料表面CVD SiC涂层的制备工艺，并对涂层的表面致密化性能进行分析。在不同的工艺条件制备SiC涂层，探讨了温度，载气流速，时间等因素对涂层的影响，利用扫描电镜和X－射线衍射仪，对涂层晶型进行分析，讨论不同条件下SiC的结晶形态，从而得出制备致密涂层的较好工艺。     

Effects of manufacturing process and surface treatments on mechanical properties of PLA/SCF composites using extrusion printing

Short carbon fiber (SCF) reinforced polylactic acid (PLA) composites were fabricated by extrusion printing, and the effects of process parameters and surface treatments on the mechanical properties of composites were studied. Based on the rheological properties of composites and the extrusion process simulation, pure PLA specimens and PLA/SCF specimens were manufactured under different printing parameters. Three kinds of surface treatment were adopted to improve the mechanical properties. The experimental results show that SCF can effectively improve the tensile strength and bending strength, but the compressive strength decreased. The specimen had the best mechanical properties when the layer height was 0.1 mm and the nozzle diameter was 0.6 mm. The mechanical properties can be further improved by coupling agent coating method, and the compressive strength was even higher than that of pure PLA specimen. The research in this paper can provide a reference for the fabrication of thermoplastic composites with excellent mechanical properties by extrusion printing.

     

An Improved Tribological Polymer-Coating System for Metal Surfaces

Aromatic thermosetting polyester (ATSP)- and polytetrafluoroethylene (PTFE)-blended composites have been shown to exhibit improved tribological performance with low wear and low friction. In this article, pure ATSP films were coated on aluminum substrates and tested as a potential protective tribological coating. The tribological performance of this coating was tested against steel, using pure sliding sphere-on-disk experiments. A fluoroadditive powder (solid lubricant) was also added to further enhance the ATSP film wear and friction properties. For comparison, a commercially available PTFE-based coating was tested under the same conditions. Results show that the ATSP/fluoroadditive film has comparable coefficient of friction to the commercial coating, but significantly lower wear. Surface analysis techniques were employed to investigate the low-friction and low-wear mechanisms seen with the ATSP/fluoroadditive. Specifically TOF-SIMS depth-profiling showed that there is a high density of fluorine element within the wear track and penetrates well below the surface of the wear track.     

Experiences from scratch testing of tribological PVD coatings

The use of PVD coatings in tribological applications becomes more and more widespread. Thus also the need to fully understand the relationships between the intrinsic properties of the coating, the properties of the coating/substrate composite and the tribological performance of the composite in different tribological systems becomes increasingly pressing. One of the tools available for tribological characterization of coatings and coating/substrate composites is scratch testing. In the current paper, Uppsala University presents a selection of results from many years of scratch testing of PVD coated components. Applications range from adhesion assessment and coating quality determination to estimation of coating fracture resistance. Examples in the form of scratch studies of PVD coatings on various high speed steels and tool steels - including failure mode anaiysis in situ SEM - are given.     

Fabrication of Carbon Nanotubes and Rare Earth Pr Reinforced AZ91 Composites by Powder Metallurgy

It can be known from a large number of research results that improving the dispersibility of CNTs can effectively opti-mize the mechanical properties of the corresponding metal matrix composites.However,the crucial issue of increas-ing the bonding of CNTs and the matrix is still unsolved.In this paper,a novel method was developed to increase interfacial bonding strength by coating titanium oxide(TiO2)on the surface of CNTs.The rare earth Pr and TiO2@CNTs-reinforced AZ91 matrix composites were successfully fabricated by powder metallurgy.Hot press sintering and hot extrusion of the milled powder was performed.After hot extrusion,the influence of TiO2@CNTs on the microstruc-ture and mechanical properties of the composites were investigated.The results showed that the coating process can improve the distribution of CNTs in Mg alloy.The CNTs refined the grains of the matrix,and the CNTs were presented throughout the extrusion direction.When the TiO2@CNTs content was 1.0 wt.％,the yield strength(YS),ultimate ten-sile strength(UTS),and elongation of the alloy attained maximum values.The values were improved by 23.5％,82.1％,and 40.0％,respectively,when compared with the AZ91 alloy.Good interfacial bonding was achieved,which resulted in an effective tensile loading transfer at the interface.CNTs carried the tensile stress and were observed on the tensile fracture.     

Mechanical and tribological properties of vapour deposited low friction coatings on Ni plated substrates

Soft steel and aluminium substrates with load-carrying layers of electroplated nickel were coated with commercially available low friction vapour deposited coatings. The mechanical and tribological properties of the coating and substrate composites were evaluated with special emphasis on the influence of the nickel layer. Two different thicknesses of the intermediate load-carrying nickel layer were tested. The samples were evaluated regarding friction and sliding wear, abrasive wear, hardness and elastic modulus, morphology and coating thickness and adhesion between substrate and coating. It was found that all the evaluated low friction coatings were possible to be successfully deposited on the intermediate nickel layer. A relatively thick intermediate nickel layer is a promising candidate for improvement of the load-carrying capacity.     

C-A型传感阀故障引起制动缸缓解不良原因分析及建议

根据C-A传感阀作用原理对传感阀故障原因及引起制动缸缓解不良原因进行系统分析,并对C-A传感阀及防尘罩结构提出改进建议。     

纤维增强金属基复合材料热机械循环加载力学模型

着重论述考虑涂层效应的纤维增强金属基复合材料的热机械加载细观力学模型.在假设基底金属为粘塑性材料,纤维与涂层为横观各向同性弹性材料的前提下,从复合材料内部组分的细观力学关系入手,利用平均应力应变的概念,分析材料在热机械载荷作用下的应力应变关系.针对金属基底的粘塑性特性,选择Bodner-Partom模型作为金属的基本本构关系,并进一步将主要问题归纳为可以数值求解的以时间为自变量的一阶常微分方程组的初值问题.     

A tribological study of electrolytic nickel-PTFE composite coatings

The potential for co-depositing PTFE particles in a metal matrix by means of electrodeposition has led to a new generation of composites that show promising tribological properties. In the present work, a study has been made of the parameters of the coating process (type of current, current density, and concentration of PTFE in the electrolyte bath) in order to optimise the properties of coatings.     

Tribological Characterisation of Air-Sprayed Epoxy-CNT Nanocomposite Coatings

Epoxy-carbon nanotube (CNT) composites are promising coating materials for wear and corrosion critical applications such as marine bearings, shafts, bolts and gears. However, there are insufficient tribological data available for design. This article described the fabrication and tribological testing of an epoxy-CNT composite coating composed of a commercial epoxy primer and commercial CNT filler. The CNT filler was pre-treated so that it was compatible with epoxy resin and was dispersed using a ball milling process. A reciprocating sliding test rig was built for the measurement of friction and wear of the coatings which were subjected to multi-pass testing using the ball-on-plate sliding geometry. The rig allowed testing with either constant or varying normal force, along with measurement of normal and tangential forces. Thus, the coefficient of friction (COF) under ramping or constant normal force could be determined. Following testing, the samples were examined using an optical microscopy to determine the severity of any galling which had taken place. The coatings were found to display encouraging properties in all aspects of testing. COF values of around 0.2 were recorded under a nominal contact pressure up to 1 GPa. This coating can be used for components which require anti-corrosion and low friction properties.     

蓝宝石镀膜方法研究

蓝宝石具有一系列优异的光学和力学性能,使其在现代镀膜领域中倍受青睐。在一些高科技领域中,蓝宝石作为重要的功能材料,为实现不同的功能,选择不同的镀膜材料来实现。介绍了蓝宝石的主要物理性能,并对其作为衬底的几种镀膜方法作了简单介绍,包括磁控溅射法、脉冲激光沉积法、金属有机化学气相沉积法、电子柬蒸发法。