MAX/金属基自润滑复合材料摩擦学研究

金属基自润滑复合材料因其具有优良的力学性能及自润滑性能而受到广泛的关注.首先，介绍MAX相的结构、性能以及MAX相固体润滑剂的应用背景和优势.综述了国内外金属基自润滑复合材料的研究进展.然后，讨论了MAX/金属基自润滑复合材料的润滑机理并建立润滑模型.最后，展望MAX/金属基自润滑复合材料的研究前景.      

金属基固体自润滑复合材料研究现状及展望

随着当今世界工业化进程的推进,金属基固体自润滑复合材料因其独特的润滑性能受到广泛的关注,成为润滑领域一个重要的研究方向.介绍了金属基固体自润滑材料的主要制备方法和特点以及固体润滑剂的主要种类、制备方法和特性,总结了近年来国内外对铜基、铝基、镍基、银基和铁基等金属基固体自润滑复合材料的研究进展,并对金属基固体自润滑复合材料未来的发展进行了展望.     

颗粒增强金属基复合材料切削加工工艺的新进展

颗粒增强金属基复合材料有着优良的物理力学性能,在国防、电子、航空航天等领域有着广泛的应用前景.但由于加工困难.限制了其推广使用.切削加工是颗粒增强金属基复合材料的精密和超精密加工主要手段,切削技术的进一步研究和发展是促进颗粒增强金属基复合材料应用的关键之一.据此,从复合材料切削加工的切削机理、切削刀具和表面完整性三个方面,介绍了国内外最新的研究成果,并指出了存在的问题和研究方向.     

金属基抗震复合材料的研究现状与展望

研制开发具有抗震性能的金属基复合材料具有广阔的发展前景，对近几年来金属基抗震复合材料的最新进展进行了系统论述，提出了金属基抗震复合材料研究中存在的问题，并对金属基抗震复合材料的应用与发展前景进行了展望。     

金属基复合材料的发展和未来

阐述了研究金属基复合材料的意义, 并着重论述了金属基复合材料的发展史、分类、研究技术的发展和现状, 指出了金属基复合材料理论研究的不足, 提出了有关界面结构模型和凝固过程的研究方向。     

金属基复合材料铸造技术发展情况

本文综合评述了国内外金属基复合材料铸造技术的研究进展以及需要进一步研究的润湿、凝固、界面反应等多方面问题,并对我公司如何开展金属基复合材料铸造技术的研究提出了建议.     

金属基陶瓷颗粒增强复合材料的制备方法

介绍了金属基陶瓷颗粒增强复合材料(metal matrix ceramic reinforced cornposites)的基体与陶瓷增强相的选择,同时指出如何有效地改善金属基体与陶瓷颗粒增强相之间的浸湿性问题.总结了烧结前期复合坯体的一些主要制备方法.又介绍了金属基陶瓷复合材料(MMC)的烧结工艺,重点介绍了通电烧结,比较了各新工艺的基本原理和优缺点,最后对金属基陶瓷颗粒增强复合材料进行了技术展望.     

颗粒增强铸造金属基复合材料

介绍了国内外对金属基复合材料的研究及应用的简单情况,重点阐述了石墨、碳化硅颗粒增强金属基复合材料的制备及其特性,以及SiCp／ZL109复合材料在175柴油机活塞上的台架试验结果。展望了铸造颗粒增强金属基复合材料的应用前景。     

陶瓷增强金属基复合材料的研究进展

介绍了陶瓷增强金属基复合材料研究的最新进展。研究了陶瓷增强剂的性能、复合材料的先进制备技术、各种金属基复合材料的性能和应用，以及复合材料研究中存在的问题和今后的发展趋势。     

界面热失配对金属基复合材料力学性能的影响

由于金属基体和增强相的热膨胀系数存在差异，金属基复合材料在制备降温过程中不可避免地产生热失配应力。研究表明，金属基复合材料热失配应力在近界面处以不同类型金属缺陷的形式进行释放，在远离界面处以热残余应力的形式保留。热失配应力释放的缺陷类型、尺寸、密度以及热残余应力的存在均会显著影响金属基复合材料的力学性能。本文阐述了界面热失配缺陷和热残余应力的产生，详细分析了界面热失配对金属基复合材料力学性能的影响，为进一步实现金属基复合材料的界面结构设计和优化提供理论基础和科学依据。     

Directionally Constrained Viscoplasticity for Metal Matrix Composites

A theoretical framework along with an experimental comparison and numerical simulation is presented, for the modeling of the viscoplastic behavior of metal matrix composites (MMCs). MMCs are finding increasing applications in aerospace structures. MMCs have strong directional properties that directly influence the evolution of the internal variables, namely, the backstress and viscoplastic strain. The model is developed within a micromechanical framework for MMCs using the equilibrium surface approach. The directional properties of MMCs are incorporated by proposing a constrained equilibrium surface, which is based on the constrained stress terms proposed. The micromechanical framework combines the viscoplastic properties of the matrix with the elastic properties of the fiber. Model-generated experimental comparisons and simulations are also presented.     

The Influence of Ni-Coated TiC on Laser-Deposited IN625 Metal Matrix Composites

IN625 Ni-based metal matrix composites (MMCs) components were deposited using Laser Engineered Net-Shaping (LENS) with Ni-coated and uncoated TiC reinforcement particles to provide insight into the influence of interfaces on MMCs. The microstructures and spatial distribution of TiC particles in the deposited MMCs were characterized, and the mechanical responses were investigated. The results demonstrate that the flowability of the mixed powders, the integrity of the interface between the matrix and the TiC particles, the interaction between the laser beam and the TiC ceramic particles, and the mechanical properties of the LENS-deposited MMCs were all effectively improved by using Ni-coated TiC particles.     

Damping behavior of discontinuously reinforced ai alloy metal-matrix composites

High damping materials allow undesirable mechanical vibration and wave propagation to be passively suppressed. This proves valuable in the control of noise and the enhancement of vehicle and instrument stability. Accordingly, the scientific community is continually working toward the development of high damping metals (hidamets) and high damping metal-matrix composites (MMCs). The MMCs are particularly attractive in weight-critical applications when the matrix and reinforcement phases are combined to provide desirable property combinations, such as high damping and low density. Inspection of the available scientific literature, however, reveals that an understanding of the precise correlation between the presence of secondary phases (either reinforcements or precipitates) and material damping has eluded investigators, partly as a result of the superposition of multiple mechanisms. As a step toward the clarification of damping phenomena in discontinuously reinforced MMCs, this article describes the damping behavior and mechanisms that are present in discontinuously reinforced MMCs, with particular emphasis on particulate-reinforced Al alloy MMCs processed using spray atomization and deposition. The operative damping mechanisms in the particulate-rein-forced MMCs are discussed in light of the data obtained from microstructural studies and damping capacity measurements. This article is based on a presentation given in the Mechanics and Mechanisms of Material Damping Symposium, October 1993, in Pittsburgh, Pennsylvania, under the auspices of the SMD Physical Metallurgy Committee.     

非连续增强金属基复合材料及其在汽车工业的应用

介绍了金属基复合材料及其制造方法，重点讨论了搅拌法工艺，概述了颗粒增强铝基复合材料在汽车工业的应用。     

Damping behavior of 6061Al/Gr metal matrix composites

The damping behavior of graphite particulate-reinforced 6061A1 alloy metal matrix composites (MMCs) processed by spray atomization and codeposition is studied. Four spray deposition experiments are made, yielding materials with graphite volume fractions of 0, 0.05, 0.07, and 0.10. A dynamic mechanical thermal analyzer is used to measure the damping capacity and elastic modulus at 0.1, 1, and 10 Hz over the temperature range of 30 °C to 250 °C. The damping capacity of the materials is shown to increase with increasing volume fraction of graphite. Hot extrusion of the spray-deposited MMCs is shown to further increase the damping capacity. The elastic moduli of the spray-deposited MMCs are reduced with the addition of graphite but are improved by hot extrusion. At low temperatures (below 150 °C), the high damping capacity of the MMCs is attributed primarily to thermal expansion mismatch-induced dislocations and the high intrinsic damping of graphite. At high temperatures (above approximately 200 °C), the damping capacity is attributed to Al/graphite interface viscosity, preferred orientation of the graphite, and the presence of dislocations.     

A Phenomenological Model for Tool Wear in Friction Stir Welding of Metal Matrix Composites

Friction stir welding (FSW) of metal matrix composites (MMCs) is advantageous because the solid-state nature of the process precludes formation of deleterious intermetallic phases which accompany melting. FSW of MMCs is complicated by rapid and severe wear of the welding tool, a consequence of contact between the tool and the much harder abrasive reinforcement which gives the workpiece material its enhanced strength. The current article demonstrates that Nunes’s rotating plug model of material flow in FSW, which has been successfully applied in many other contexts, can also help us understand wear in FSW of MMCs. An equation for predicting the amount of wear in this application is developed and compared with experimental data. This phenomenological model explains the relationship between wear and FSW process parameters documented in previous studies.     

Role of bile acids in duodenal migrating motor complexes in dogs

Previous studies have suggested that enterohepatic circulation of bile acids is essential for regular cycling of duodenal migrating motor complexes (MMCs). The present study was an attempt to clarify the role of bile acids in the enterohepatic circulation system in initiating duodenal MMCs. Seven dogs underwent total external biliary diversion that resulted in the loss of MMCs originating from the duodenum. Sodium ursodeoxycholate (6 mg/kg/hr) was then given either through the portal vein or a peripheral vein, and motility of the gastrointestinal tract was serially recorded. When sodium ursodeoxycholate was given either through the portal vein or a peripheral vein during external biliary diversion, duodenal MMCs restarted. The cyclic change in plasma motilin levels during an MMC cycle as induced by sodium ursodeoxycholate was almost the same as in a normal MMC cycle. Total bile acid concentration in the portal vein changed cyclically with MMC cycles when bile flow was intact but did not change cyclically with MMC cycles restarted by intravenous bile salt infusion. Bile acid stimulation of putative receptors existing between the portal vein and intrahepatic bile ducts may be involved in initiating normal duodenal MMC cycles.     

热压技术在新型P/M金属基复合材料中的应用

反应烧结是合成颗粒增强金属基复合材料 (MMCs)的新工艺。与传统P M工艺相比 ,通过化学反应在金属基体中产生增强颗粒有诸多优势。由Al TiO2 B经反应烧结制备的Al (Al2 O3+TiB2 )MMCs便是这样一个例子。本文用热压技术将多孔Al (Al2 O3+TiB2 )MMCs致密化并得到了很好的力学性能。Al ( 10 2 %Al2 O3+9 2 %TiB2 ) (体积分数 )的弹性模量、抗弯强度和弯曲最大应变分别为 10 5GPa、50 9MPa和 5 0 %。如果复合材料的成分改变成Al ( 5 4 %Al2 O3+4 9%TiB2 ) (体积分数 ) ,其性能则分别为 89GPa ,311MPa和 8 2 %。文中亦将热压Al (Al2 O3+TiB2 )MMCs的结果与用其他致密化技术处理此材料的结果 ,以及热压其他类似材料的结果进行了比较。