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1.
利用MM-200型磨损试验机考察了载荷对纳米SiO2、TiO2、Al2O3与石墨混合填充PTFE复合材料摩擦磨损性能的影响,采用扫描电子显微镜观察分析磨损表面形貌及磨损机理。结果表明,纳米材料及其与石墨混合都可以不同程度地提高PTFE的耐磨性,而它们对PTFE耐磨性的提高程度各不相同,其中以纳米SiO2-石墨填充PTFE复合材料的磨损质量损失最小,纳米Al2O3-石墨填充PTFE复合材料的磨损质量损失较大;填充PTFE复合材料同钢对磨时的摩擦系数表现出不同的性能,纳米SiO2-石墨填充PTFE的摩擦系数与纯PTFE相差不大。  相似文献   

2.
以Cr-Si-Ni合金粉末为原料、利用激光熔敷技术在A3低碳钢表面上制得了以金属硅化物Cr3Si为增强相,以Cr2Ni3Si复杂金属硅化物为基体的快速凝固Cr3Si/Cr2Ni3Si复合材料冶金涂层,分析了该涂层的显微组织,并分别在干滑动磨损及二体磨料磨损条件下测试了该涂层的耐磨性能。研究结果表明,由于激光熔敷Cr3Si/Cr2Ni3Si快速凝固复合材料涂层组织细小、均匀,在滑动磨损过程中不易与对偶件粘着、在磨料磨损过程中具有很高的抗切削抗剥落能力,因而在干滑动磨损及二体磨料磨损条件下涂层均具有优良的耐磨性能。  相似文献   

3.
采用日本产A G-10TA 型电子万能试验机对挤压铸造ZA 22/Al2O3短纤维复合材料的高温抗拉强度进行了测定, 并用Friend 修正的混合律模型对该试验结果进行了理论分析, 结果表明ZA 22/Al2O3短纤维复合材料及其基体的强度均随温度升高而下降, 但ZA 22合金基体的强度下降幅度更大。任一纤维体积分数的复合材料, 均存在一临界转变温度T crit; 超过该温度, 复合材料强度大于基体强度。纤维体积分数越大, 所需临界转变温度越低。在本试验中, V f 为15% 和20% 的复合材料的Tcrit分别为123℃和87℃。任一温度下, 复合材料均存在一临界纤维体积分数, 超过该纤维体积分数, 复合材料强度高于基体强度。温度越高, 临界纤维体积分数越低。对ZA 22/Al2O3短纤维复合材料来说, Friend 模型中的经验参数C3 的取值随温度升高而降低。  相似文献   

4.
磷酸盐溶液中碳纤维表面电化学改性   总被引:2,自引:4,他引:2       下载免费PDF全文
对比研究(NH4)2HPO4和NH4H2PO4两种不同电解质对碳纤维电化学改性效果的影响。通过拉丁方试验,研究了各改性参数对纤维表面改性效果的影响程度,采用XPS、AFM、BET技术对纤维表面化学组成、形貌及其比表面积的变化进行了表征分析。结果表明:以(NH4)2HPO4为电解质处理时改性效果主要受相对电流密度的影响,而以NH4H2PO4为电解质时电解液浓度是最主要的影响因素;在(NH4)2HPO4电解液中,纤维表面氧化刻蚀温和,改性效果显著,层间剪切强度可提高到79.8MPa,而在NH4H2PO4电解液中,纤维表面受到较强烈氧化刻蚀,本体强度损失较大,复合材料层间剪切强度仅能提高到70.8MPa。  相似文献   

5.
利用挤压铸造法制备了Al2O3(15%)/Al-12Si复合材料,并采用透射电镜动态拉伸技术对复合材料的裂纹形成及微观断裂过程进行了原位观察,发现该复合材料的纤维/基体界面是破坏路径之一,并发现了纤维中裂纹形成及扩展至完全破坏的现象.  相似文献   

6.
肖轶  徐呈艺  Ryou Min  曹健 《材料导报》2018,32(24):4329-4333, 4338
在低碳钢表面利用等离子堆焊技术分别制备Fe50堆焊层及添加40%(质量分数)微米和纳米Cr3C2的(Fe50+40%微米/纳米Cr3C2)复合堆焊层,比较研究添加不同粒径的Cr3C2对Fe50合金堆焊层的显微组织与磨损性能的影响。采用X射线衍射仪(XRD)分析堆焊层的相组成,利用扫描电镜(SEM)和能谱分析仪(EDS)观察堆焊层的显微组织形貌及微区成分,通过显微硬度计测试了堆焊层的硬度分布,使用滑动磨损及冲击磨损试验机分别考察了复合堆焊层的磨损性能。结果表明:Fe50等离子堆焊层组织主要由柱状晶α-Fe及其间的网状共晶α-Fe+Cr23C6组成;而Fe+40%微米/纳米Cr3C2堆焊层凝固方式为过共晶,由大量的先共晶碳化物及其间细密、均匀的枝晶与共晶组织组成,并增加了γ-Fe、Cr7C3和未熔Cr3C2等相;但Fe+40%纳米Cr3C2涂层比Fe+40%微米Cr3C2涂层析出更多且细小、致密的先共晶碳化物。与Fe50等离子堆焊涂层相比,Fe+40%微米Cr3C2涂层的显微硬度、滑动磨损性能及冲击磨损性能分别提高了21%、1.5倍和0.8倍;而Fe+40%纳米Cr3C2涂层的显微硬度、滑动磨损性能及冲击磨损性能则分别提高了34.1%、2.4倍和1.7倍,表面的犁沟和剥落及塑性变形明显减少,耐磨性能显著提高。因此,添加纳米Cr3C2颗粒可以显著细化铁基合金等离子堆焊层的显微组织并提升其耐磨性能。  相似文献   

7.
本文研究了A3S2/Fe复合材料的烧结特性、透气性和纤维增强效果,分析了烧结过程中材料宏观结构和微观组织的形成机理.实验结果表明:纤维增强A3S2/Fe复合材料在900~1000℃具有良好的烧结性能,烧成后表层存在一定厚度的硬化层;纤维增强效果显着.材料抗压强度达17~23MPa,相对透气系数为4.30~9.69cm3/(cm2·s·atm).已能满足实际应用的需要.  相似文献   

8.
为适应20℃~-200℃ 温度的适用范围,采用固相法制备了Bi1.6Pb0.4Sr2Ca2Cu3O10-x超导材料,用摩擦磨损试验机测试了Bi1.6Pb0.4Sr2Ca2Cu3O10-x从液氮温度至室温的摩擦学性能。结果表明 : 在室温 20℃下,Bi1.6Pb0.4Sr2Ca2Cu3O10-x与对偶件轴承钢盘对摩时,摩擦系数约为0.35,当温度降到超导转变温度以下时(液氮温度-170℃)摩擦系数大幅度降低,Bi1.6Pb0.4Sr2Ca2Cu3O10-x超导态摩擦系数为正常态值的一半,实验证明了电子激励对摩擦能量耗散的作用。为改善室温下Bi1.6Pb0.4Sr2Ca2Cu3O10-x摩擦学性能,掺杂不同质量分数 Ag作为润滑组元,制备了Bi1.6Pb0.4Sr2Ca2Cu3O10-x超导固体润滑复合材料,取得良好耐磨减摩效果。Ag掺杂不影响Ag/Bi1.6Pb0.4Sr2Ca2Cu3O10-x复合材料的超导性,在正常载荷和滑动速度下10 wt%Ag/ Bi1.6Pb0.4Sr2Ca2Cu3O10-x复合材料摩擦系数为0.2~0.3,磨损率为4.57×10-4 mm3·(N·m)-1。  相似文献   

9.
Al2O3颗粒粒径和含量对α-Al2O3/Cu复合镀层性能的影响   总被引:4,自引:0,他引:4       下载免费PDF全文
本文研究了复合电沉积法制备的α-Al2O3/Cu 复合材料的性能和磨损特征, 测定了Al2O3粒径在0. 5~ 5Lm, 含量在4~ 16% 时Al2O3/Cu 复合镀层的硬度和磨损率, 用扫描电镜对磨损形貌进行了分析, 并对其磨损机制进行了探讨。结果表明, 镀层中硬度随Al2O3含量增加呈线性增长, 且含大颗粒Al2O3镀层的硬度略高于小颗粒镀层,Al2O3颗粒含量和粒径大小对磨损率和磨损机制有显著影响。  相似文献   

10.
Al2O3-SiO2纤维增强ZL108合金复合材料的强度特性   总被引:3,自引:1,他引:2       下载免费PDF全文
用低成本的Al2O3-SiO2系纤维作为增强相,通过加压铸造法制作ZL108合金复合材料,并对该复合材料和ZL108合金进行不同温度下的时效处理和压缩试验。通过DSC、EPMA和TEM分析认为:经488K、0.5h时效处理(T6处理)的Vf 20%的复合材料在573K以下的压缩屈服强度低于ZL108合金,是由于基体中的Mg与Al2O3-SiO2纤维在加压铸造过程中起化学反应而生成MgAl2O4,损耗了基体中的大量Mg,导致基体铝合金时效硬化效果很差,所以压缩屈服强度低下。623K、720h保温后的Vf 20%的复合材料的压缩屈服强度比ZL108合金要高得多,是由于在这种温度环境下对ZL108合金来说是过时效,所以纤维的增强怍用显得明显。在高温(673K)下Vf 20%的复合材料的屈服强度比ZL108台金高一倍左右。不论在什么温度场合下Vf5%的复合材料的屈服强度比Vf 20%的复合材料都低。  相似文献   

11.
硅酸铝纤维增强铝基复合材料的疲劳断裂特征   总被引:1,自引:0,他引:1       下载免费PDF全文
采用压力铸造法, 制得Al2O3?SiO2短纤维增强的铝合金复合材料, 对其弯曲疲劳性能进行了测试, 并详细观察了疲劳裂纹的形成及扩展方式。结果表明: Al2O3?SiO2f/ ZL 108复合材料存在 多种疲劳源; 疲劳裂纹的扩展是通过主裂纹与裂尖前方孔洞的相互联接而进行的, 是不连续的, 沿着纤维及渣球密集的路径扩展; 疲劳过程中主裂纹的形成消耗了大部分的疲劳寿命, 一旦主裂纹形成就快速扩展瞬间断裂。该复合材料的断裂宏观上是脆性的, 但微观上显示出塑性的特征。  相似文献   

12.
纤维长度对M/ZL109复合材料强度及可靠性的影响   总被引:1,自引:0,他引:1  
对在相同的挤压工艺参数的条件下,用具有不同的长度分布及平均长度的莫来石短纤维与ZL109复合得到复合材料,然后比较这些复合材料的抗拉强度及其分散度,考察和分析了纤维长度分布状况及平均长度对复合材料的强度及强度数据分散性的影响规律。  相似文献   

13.
Friction stir processing (FSP) has been used to produce metal matrix composites by incorporating reinforcement particles in an AA6061-T6 matrix. Two types of particles (Al2O3 and SiC) were tested. Powder was placed into a mechanized square section groove on a plate surface and then sealed before FSP. This study investigates the effect of several strategies for reinforcement (number and direction of FSP passes) on the wear resistance behavior of friction stir-processed Al-SiC/Al2O3 composites. The distribution and size of the particles in the friction stir-processed zone were studied by optical and scanning electron microscopy. Ball-on-disk test was performed on both base material and surface metal matrix composites (SMMCs), and both friction coefficient and specific wear rate (SWR) were correlated with particle distribution and metallurgical effects on the metallic matrix. For all strategies and for both types of reinforcing particles used in this study, the friction coefficient decreases with respect to the base material. Moreover, the SWR is reduced for the conditions of one single FSP pass and two passes with opposite directions, when SiC are used. However, this positive effect has not been detected with Al2O3. Wear mechanisms in base metal and in SMMCs are compared and discussed in detail.  相似文献   

14.
The effect of fibre orientation on the dry sliding wear of continuous B(SiC) fibre reinforced aluminium alloy composites was investigated using a pin-on-disc wear testing machine. The metal-matrix composites (MMC) samples were tested in the normal (N), parallel (P) and antiparallel (AP) orientations sliding against a steel counter disc at a fixed speed of 1 m s–1 under loads of from 12 to 60 N.The results showed that for the matrix alloy and MMCs, the average wear increased linearly with load. Wear of the MMCs was insensitive to fibre content but for composites with fibre contents at or above the minimum of 16 vol% used for this work, the wear rate was about 18% of that of the unreinforced matrix. Fibre orientation had a minor effect on wear rate; the N orientation gave the lowest wear rate with the AP orientation slightly higher and the P orientation significantly higher.The average coefficients of friction of the MMCs in N and AP orientations decreased linearly with increased wear rate and non-linearly with increased load, but the P orientation was insensitive to either variable.It was concluded from these results and a metallographic examination that the mechanism of wear of MMCs was essentially oxidative wear of the matrix. The hard fibres modified this to slightly different degrees depending on their orientation relative to the wear surface and sliding direction.  相似文献   

15.
Jute fibre reinforced polyester composites were developed and characterized for friction and sliding wear properties. Effect of fibre orientation and applied load on tribological behaviour of jute fibre reinforced polyester composites were determined. It is found that wear resistance was maximum in TT sample, where fibres were normal to sliding direction. Wear rate under sliding mode follows this trend; WTT < WLT <WLL LL sample showed higher capability to sustain the load whereas lowest wear resistance found in this case. The coefficient of friction found highest for TT sample and lowest for LT sample. The coefficient of friction decreased with increase of applied load. Worn surfaces were analysed and discussed with the help of SEM.  相似文献   

16.
Abstract

Metal matrix composites are considered as a distinct category of the advanced materials, which have low weight, high strength, high modulus of elasticity, low thermal expansion coefficient and high wear resistance. Among them, Al–Al2O3 composites have achieved significant attention due to their desired properties. In the present research, Al–Al2O3 composites with 5 vol.-% alumina were produced by stir casting at a temperature of 800°C. Two different particle sizes of alumina were used as 53–63 and 90–105 μm. The microstructure of the samples was evaluated by SEM. In addition, the mechanical properties of the samples were measured, and hence, the optimum temperature and particle size of alumina to be added to the Al matrix were determined. The results demonstrated the positive effect of alumina on improving the properties of Al–Al2O3 composites.  相似文献   

17.
In the present work, friction material composites were proposed to be used as automotive friction materials. The composites were reinforced by agricultural fibres of corn, palm, and sugar bars. The conventional friction materials based on asbestos cause serious lung diseases and being cancerous potential. The aim of the present work is to replace them by the proposed composites because they are environmentally friendly friction material for brake lining and clutch facings. Agricultural wastes of sugar bars, corn and palms fibres were prepared to obtain fibres of length less than 5 mm. The fibre materials were mixed by carbon, barium sulfate, silica, metallic powders and phenol formaldehyde. The proposed composites were pressed in the die at 105°C temperature. The produced specimens were subjected to machining processes to obtain the cylindrical form of 8 mm diameter. Experiments were carried out using test rig designed and manufactured to measure both friction and wear. It consists of a rotating hollow flat disc made of carbon steel, with an outside diameter of 250 mm and 16 mm thickness. The experiments investigated the effect of agriculture fibre wastes (corn, sugar bars, and palms fibres) on friction coefficient and wear. Wear mechanisms of the proposed composites were characterized by scanning electronic microscopy. The tribological properties of the proposed composites materials were compared to three commercial brake linings. Based on the experimental results it was found that, addition of agriculture fibre wastes (corn, sugar bars, and palms fibres) to composites materials increased friction coefficient and decreased wear. Friction coefficient slightly increased, while wear drastically decreased with increasing fibres content. The maximum friction value (0.58) was obtained by composites containing 30 wt.% iron and 25 wt.% sugar bar fibres. The corn fibres were more compatible with aluminum powder where it gave the highest friction coefficient and relatively lower wear compared to other composites. Wear resistance of the tested composites containing bunches and aluminum represented the lowest values among composites containing corn and bunches fibres. The lowest wear values were observed for composites containing 25 wt.% corn fibres and 30 wt.% aluminum and composites containing 20–25 wt.% sugar bar fibres.  相似文献   

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