应用模压铸造法制造的Al2O3f/SiCp混杂增强铝基复合材料的摩擦磨损行为（英文）

研究了通过模压铸造方法制造的氧化铝纤维与碳化硅颗粒混合增强铝基复合材料的干摩擦磨损性能。分别在室温、110℃,以及150℃条件下,进行了恒速0.36m/s(570r/min)的销盘式摩擦磨损实验。采用扫描电子显微镜观察干磨损表面特征,采用Arrhenius作图法研究相对磨损率,以便于进一步研究磨损机制。此外,讨论了纤维的方向性和纤维与颗粒的混合比作用。     

Microstructure evolution of rare earth Pr modified alumina-silicate short fiber-reinforced Al-Si metal matrix composites

Al-Si metal matrix composites (MMCs) reinforced with 20 vol.% alumina-silicate shot fibers (Al2O3-SiO2(sf)) were fabricated by an infiltration squeeze method. Pure Pr metal was added into these composites. The effect of Pr addition on the microstructure evolution of Al-Si MMCs was investigated by SEM,TEM,and EDS. Pr addition is favorable to make uniform microstructures with the modified eutectic Si crystal. PrAlSi phase with high contents of Pr and Si is observed on the interface between the fiber and the m...     

硅酸铝短纤维增强Al-12Si合金复合材料的磨损行为

用挤压铸造法制备了低体积分数（３％～７％）的硅酸铝短纤维增强Ａｌ１２Ｓｉ合金复合材料,并利用销盘磨损试验机研究了材料在干摩擦条件下的磨损行为。磨损试验结果表明：硅酸铝短纤维加入到Ａｌ１２Ｓｉ合金明显提高抗磨损能力,随纤维体积分数的增加该复合材料的耐磨性逐渐增强。金相观察和测试表明：基体合金和复合材料的磨损区由硬化层和变形层组成,断裂的ＡｌＳｉ共晶相沿滑动方向重新分布排列形成了硬化层;而复合材料硬化层由于破断的硅酸铝纤维和破碎的ＡｌＳｉ共晶相的共同作用,使该硬化层硬度高于基体合金硬化层的硬度,从而使复合材料表现出优异的耐磨性。并根据试验结果提出了基体合金和复合材料的磨损机制模型     

反应自生氧化铝颗粒增强铝基复合材料

向铸铝ADC12熔体中添加硫酸铝铵,由反应分解的Al2O3原位生成了颗粒增强铝基复合材料。SEM观察表明,Al2O3颗粒在铝基体中细小弥散分布,形成球形、不团聚的增强体颗粒;Al2O3颗粒增强铝基复合材料中的片状共晶硅的数量比未增强合金的少,且Al2O3邻近处的针状共晶硅非常精细。与基材相比,Al2O3颗粒增强铝基复合材料的耐磨性较基材的提高了1~2倍,硬度提高了15%,且由硫酸铝铵反应自生成复合材料的耐磨性优于添加氧化铝形成的复合材料的。     

基体合金对连续Al2O3f/Al复合材料微观组织及拉伸强度的影响

选用Nextel610型Al2O3纤维作为增强体,采用真空气压浸渗法制备了纤维体积分数40%、基体合金分别为1A99、ZL210A、ZL301及7075合金的单向连续Al2O3f/Al复合材料,并用NaOH溶液萃取出Al2O3纤维,研究了基体合金对连续Al2O3f/Al复合材料的致密度、纤维损伤及拉伸强度的影响。结果表明：基体合金对连续Al2O3f/Al复合材料的致密度和微观组织有明显影响,其中连续Al2O3f/ZL301复合材料致密度最高为99.2%,组织缺陷最少;连续Al2O3f/1A99复合材料致密度最低为96.8%,这种差异是由于不同基体与纤维之间润湿性不同导致的。不同基体与纤维发生了不同程度的界面反应,最后表现为对纤维的损伤程度不同。连续Al2O3f/1A99、Al2O3f/ZL210A、Al2O3f/ZL301及Al2O3f/7075四种复合材料的拉伸强度分别为465MPa、479MPa、680MPa和389MPa,缺陷、纤维损伤和界面结合强度是影响连续Al2O3f/Al复合材料强度的主要因素。     

Microstructures and properties of graphite and Al2O3 short fibers reinforced Mg-Al-Zn alloy hybrid composites

Graphite and Al2O3 short fibers reinforced Mg-Al-Zn alloy hybrid composites were fabricated by perform squeeze-infiltration route. The effects of the volume of graphite particles on the microstructure, mechanical properties and tr/bological behavior were investigated under the conditions of constant size of graphite particle and volume of Al2O3 short fiber. The results reveal that the uniform distribution of the reinforced graphite particles and Al2O3 short fiber can be obtained by this technique, and they have strong bonding with the metal matrix. Increasing graphite volume results in decrease in hardness, the ultimate tensile strength whereas the Al2O3 short fiber makes contribution to the increase in hardness of the composite. The composite exhibits good wear resistance, small wear mass loss and low coefficient of friction as compared with the metal matrix. The wear mechanisms transit from oxidation wear, abrasion wear into delamination wear as the applied load is increased, and a film of lubricant covering almost entire surface of specimen, is found to be formed, which separates the wear surfaces from metal to metal contact and thus improves the tribological properties.     

碳纤维含量对Al2O3+C/ZL109混杂复合材料摩擦磨损性能的影响

利用挤压铸造法制备了A1203 C／ZLl09短纤维混杂金属基复合材料，并探讨了A1203纤维体积分数为12％时，C纤维含量对该混杂复合材料摩擦磨损性能的影响。结果表明：随着C纤维体积分数的增加，复合材料的摩擦因数和磨损率逐渐降低。12％A1203和4％C短纤维的协同作用使复合材料从轻微磨损到急剧磨损的临界转变载荷比基体合金提高了1倍。当载荷低于临界载荷时，复合材料的主要磨损机制为犁沟磨损和层离，C纤维的加入有利于磨损表面裂纹尺寸的减小。但随着载荷的逐渐增加并发生严重磨损时，基体和复合材料的磨损机制均为严重的粘着磨损甚至局部熔化磨损。     

Effect of alumina short fiber and air-cooling processing on solidification microstructure and tensile properties of Al2O3/Al-15Si composites

The effect of microstructure variation by addition of alumina short fiber and optimization of tensile properties by air-cooling processing in Al2O3/Al-15Si composites were studied.The results show that in Al-015Si alloy matrix composites with 14% and 30%(volume fraction)fiber,the primary silicon is hardly refined,but the eutectic silicon is effectively refined and granulated.Granulation of some eutectic silicon mainly happens in fiber segregation areas.Refining and granulation of the eutectic silicon are related to the physical constraint arising from the fiber,After the 30%Al2O3/Al-15Si composite was remelted and air-cooled,the number of the eutectic silicon on the surface of the fiber increases,which results in the improvement of fiber/matrix interface and tensile properties for the as-cast composite,Air-cooling processing may be reliable for the optmization of the microstructure and properties of fiber reinforced hypereutectic Al-15Si alloy composites.     

用单摆划痕法研究Al2O3f/Al-9Si合金在不同冲击速度下的磨损行为

为揭示MMCs材料的冲击磨损机理 ,采用单摆划痕法对Al2 O3f/Al 9Si合金耐冲击磨损行为进行了研究 ,结果表明 :(1)在 3m/s冲击速度下 ,随着增强相的体积分数增多 ,Al2 O3f/Al 9Si合金抗冲击磨损性降低。在 4m/s冲击速度下 ,2 0 %Al2 O3f/Al 9Si合金具有最高的抗冲击磨损性 ,而 2 5 %Al2 O3f/Al 9Si合金的抗冲击磨损性最弱。对同一种Al2 O3f/Al 9Si合金材料 ,冲击速度为 4m/s时的耐冲击磨损性优于速度为 3m/s时的的耐冲击磨损性。(2 )在冲击磨损过程中 ,Al2 O3f/Al 9Si合金表面出现严重的犁沟和伴随发生的Al2 O3 短纤维被拉出基体形成空位的现象     

Al2O3纤维增强铝基复合材料储能焊接头微观组织分析

应用自制微型储能电阻焊机对Al2O3纤维增强铝基复合材料进行了点焊连接，分析了接头的组织形貌。在储能焊接头中形成了规则的扁平熔核，复合材料基体与熔核金属过渡良好。极短的焊接时间和大的冷却速率使共晶Si显著细化。细小的共晶Si颗粒均匀分布于铝基体中，形成与MMCs不同的基体组织。少量Al2O3纤维发生了一定程度的破碎，大部分纤维仍保持其原有的形貌特征，随机分布于熔核金属基体中。适当增大电极压力，焊前对复合材料做除氢处理并保持干燥是减小和消除气孔、提高和改善MMCs储能焊接头质量的有效途径。     

高性能陶瓷内衬复合煤粉喷枪的研制

采用燃烧合成方法制备了Al2O3陶瓷内衬复合煤粉喷枪,但单一的Al2O3陶瓷内衬层韧性差,抗热震性能低,造成喷枪的寿命短.通过在(CrO3+AD燃烧体系中添加ZrO2组元,采用SHS重力分离技术,制备出了高强度、高韧性的陶瓷内衬复合弯管煤粉喷枪,陶瓷内衬层为具有共晶结构的Al2O3=ZrO2复相陶瓷.在共晶结构中,ZrO2纤维直径可达到纳米/微米尺度,从而使陶瓷基体得以强化;同时棒状共晶结构的生长取向分布,又使陶瓷因棒晶桥接与拔出得以韧化,改善了喷枪陶瓷内衬的高温强度和耐磨性,有效地提高了煤粉喷枪的使用寿命.     

连续纤维增主基复合材料研究概况

重点了介绍了连续纤维境强钛基复合材料的３种复合方法,即箔材－纤维－箔材法、等离子喷射涂层法和物相沉积法,开发的强化纤维有ＳｉＣ纤维和Ａ１２Ｏ３单晶纤维,并介绍了它们的研究进展,最后讨论了一些复合材料的性能循呼复合材料的损伤评价技术。     

原位生成Al2O3、TiB2和Al3Ti/Al复合材料的热循环行为

本文研究了Al-TiO2-B系原位生成Al2O3、TiB2和Al3Ti/Al颗粒增强铝基复合材料的热循环行为，研究结果表明了纯铝及B／TiO2摩尔比分别为0、1和2的颗粒增强铝基复合材料的热循环行为具有以下结果，纯铝和复合材料热循环后均产生了残余应变和滞后环；Al-TiO2-B系列复合材料热循环应变的各项指标均比纯铝基体大大降低，且具有较小的内耗功和较好的热稳定性，可以预测其具有较高的热疲劳寿命，热循环曲线能很好的评估复合材料在温度循环变化的环境中工作时的热稳定性和热疲劳。     

Solute segregation in an Al2O3f／Al-4.5Cu alloy composite during solidification at different cooling rates

An Al2O3f/Al-4.5Cu composite was made by squeeze casting. The solute segregation in the composite at different cooling rates was studied. The results indicate that the primary crystal of AI-4.5Cu alloy nucleates and grows in the interstice between fibers. The fiber surface cannot serve as site for the heterogeneous nucleation of a primary dendrite. There exists an increasing Cu concentration gradient from the center of the interstice between fibers to the interface or the grain boundaries. There are the eutectic phases around the fibers. The solute segregation in the matrix increases with the cooling rate rising. The amount of eutectic phases followed by imbalance crystalline can be numerically calculated with Clyne-Kurz formula.     

金属基复合材料相界面区力学性能显微力学探针分析

雾化喷射沉积成型２０１４铝合金＋１５％ＳｉＣｐ和１８Ｎｉ马氏体时效钢＋１０％（Ａｌ２Ｏ３）ｐ金属基复合材料表现出加速时效行为。采用显微力学探针技术研究了复合材料的时效行为，发现在增强颗粒附近存在明显的弹性模量和硬度的梯度分布１，是热错配应力造成的位错密度分布引起的析出相梯度分布的结果。     

Solidification microstructures in a short fiber reinforced alloy composite containing different fiber fractions

Al2O3 short fiber reinforced aluminium alloy has a lot ofsuperior properties, including low weight, low thermalexpansioncoefficient,highstrength-to-weightandstiffness-to-weight ratio, high-temperature resistance, high corrosionresistance and so on. All these excellent propertiespromise the material a good application perspective in theaerospace automotive, and mechanical engineering areas.Despite the widespread application of the material,however, there have, as yet, been few reports available…     

柴油发动机活塞用铝基材料研究进展及失效分析

活塞作为柴油发动机的核心部件之一,恶劣的服役工况对其材料有特殊的要求。概述了活塞用铝基材料的发展状况,包括合金系(Al-Cu-Si系、Al-Cu-Ni-Mg系、共晶型Al-Si-Cu-Mg系和过共晶型A1-Si-Cu-Mg系)与复合材料系(SiC/Al基复合材料、Al_2O_3/Al基复合材料和TiC、TiB_2/Al基复合材料等),并介绍了不同材料的适用范围。同时,归纳了常见活塞铝基材料的失效机制,包括磨损、机械损伤以及顶部开裂等。其中,活塞因磨损造成的失效在统计活塞失效机制中所占比例较大,具体可分为粘着磨损失效和磨粒磨损失效。针对活塞磨损失效提出了相关改善措施,如材料成分选取和制备方法选取等。此外,针对柴油发动机在实际运行工况中,因活塞所处部位存在润滑油不完全燃烧造成的含硫、氮等腐蚀性气氛而加速磨损的问题,可依托该气氛与相应增强相的反应,使其接触表面生成自润滑膜而减少甚至抑制磨损,进而延长柴油发动机活塞的使用寿命。     

Characterization of Al-12Si alloy and its composites in dry sliding friction and wear at elevated temperature

1　INTRODUCTIONDiscontinuousreinforcementsreinforcedalu minumalloycomposites(DRACs)havesuperiorwearproperty ,especiallyhighseizureresistanceatelevatedtemperaturecomparedwithcommonaluminumal loys ,whichhavebeenreceivedconsiderableattentionin pasttwodecades[13] .TherearereportsaboutDRACsusedinpistonorblockin Ref.[4 ].Toim provethefrictionandwearpropertiesofaluminiumalloysfurther ,thehybridcompositesrepresentedthemergingoftwophilosophiesintribologicalalloyde sign—hard reinforcementsreinf…     

C/Al2O3复合材料的固体粒子冲蚀行为与磨擦磨损性能研究

以溶胶浸渍热处理技术路线制备的碳纤维布叠层缝合预制件增强Al₂O₃(C/Al₂O₃)复合材料为对象,以刚玉粉为介质,研究了复合材料的固体粒子冲蚀行为,按照GB5763-2008规定的条件研究了复合材料的磨擦磨损性能。室温下,复合材料冲蚀率随着冲击角度与送粉量的增大而增加;温度升高,由于机械冲击和热冲击的双重作用,冲蚀率显著变大。在GB5763-2008规定的条件下,C/Al₂O₃复合材料具有稳定的摩擦系数和很低的磨损率。结合微观形貌分析,探讨了复合材料的冲蚀与磨损机理。得益于连续碳纤维的补强增韧作用,即使基体致密度低于单体Al2O3陶瓷,C/Al₂O₃复合材料在冲蚀和磨损时不会发生脆性断裂,使用安全性优于单体Al₂O₃陶瓷。     

Abrasive wear characteristics and mechanisms of Al2O3／PA1010 composite coatings

The abrasive wear characteristics of Al2O3/PA1010 composite coatings on the surface of quenched and low-temperature temper steel 45 were tested on the tumplate abrasive wear testing machine and the same uncoated steel 45 was used as a reference material. Experimental results showed that the abrasive wear resistance of Al2O3/PA 1010 composite coatings has a good linear relationship with the volume fraction of Al2O3 particles in Al2O3/PA1010 composite coatings, and the linear correlative coefficient is 0.979. Under the experimental conditions, the size of Al2O3 particles (40.5-161.0μm) has little influence on the abrasive wear resistance of Al2O3/PA1010 composite coatings. By treating the surface of Al2O3 parti-cles with a suitable bonding agent, the distribution of Al2O3 particles in matrix PA1010 is more homogeneous and the bonding state between Al2O3 particles and matrix PA1010 is better. Therefore, the Al2O3 particles in Al2O3/PA1010 compos-ite coatings make the Al2O3/PA1010 composite coatings have better abrasive wear resistance than PA1010 coatings. The wear resistance of Al2O3/PA1010 composite coatings is about 45% compared with that of steel 45.