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《材料导报》2020,(16)
航空航天等领域的快速发展对Al_2O_3陶瓷表面加工质量的要求越来越高。目前,磨削加工由于精度高、材料去除率高而成为陶瓷表面加工最主要、最常用的方法,因此,建立磨削加工方式、陶瓷表面质量和力学性能之间的联系具有十分重要的意义。本工作利用精密研磨抛光机和磨床对Al_2O_3陶瓷进行表面加工,探讨了不同磨盘转速、磨盘/磨床砂轮目数、砂轮进刀量、磨床横向平移速度等不同磨削加工条件对陶瓷表面质量(材料表面粗糙度、表面形貌、表面残余应力)和力学性能的影响。研究结果表明:相比于磨盘加工,磨床加工对Al_2O_3陶瓷表面质量的影响较大,表现为磨床加工后的粗糙度数值较大,且磨削表面产生了较为明显的加工划痕。Al_2O_3陶瓷在磨削加工中的去除方式主要为脆性去除和延性域去除,加工后其表面残余应力均为压应力。特别地,在高的磨盘或砂轮目数、大的磨盘转速、较小的砂轮进刀量以及大的磨床平移速度情况下,Al_2O_3陶瓷以延性域去除为主,表面残余压应力最高达到-241 MPa。Al_2O_3陶瓷的力学性能是由表面粗糙度、表面微观形貌、表面残余应力共同作用的,随着陶瓷表面粗糙度的减小、残余压应力的增大,陶瓷弯曲强度提高,最高可达528 MPa。 相似文献
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对磨削加工后的纳米结构陶瓷涂层进行磨损性能试验.磨损试验首先对纳米结构陶瓷涂层Al2O3/13TiO2的圆柱形工件进行外圆磨削加工,然后将各种不同条件下磨削加工后的圆柱工件装夹到立式铣床的主轴上,进行定速、定载荷的磨损性能试验.磨损性能试验时,圆柱工件在旋转的同时与往复运动的长方形氮化硅陶瓷棒进行滑擦,在其圆柱表面形成磨损沟槽.使用扫描电子显微镜和表面轮廓仪对纳米陶瓷涂层的磨损沟槽进行观察与评定,并与传统陶瓷涂层的磨损沟槽进行对比与分析.为进一步揭示纳米陶瓷涂层的磨损机理,使用有限元法对接触区的应力场进行模拟,并分析纳米陶瓷涂层裂纹的形成与扩展.讨论了磨削工艺参数以及涂层晶粒大小对纳米结构陶瓷涂层耐磨损性能的影响. 相似文献
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采用热压工艺制备了添加固体润滑剂MoS2、BN、CaF2的Al2O3/TiC陶瓷材料,测量了其力学性能和分析了其显微结构.结果表明,添加固体润滑剂的Al2O3/TiC陶瓷比未添加时的力学性能有大幅下降,其中Al2O3/TiC/CaF2陶瓷材料的力学性能最好,当CaF2含量为10%时,Al2O3/TiC/CaF2陶瓷材料的强度和硬度最高,分别达到了589MPa和HV1537;而添加BN的Al2O3/TiC陶瓷材料的力学性能最差.XRD衍射结果和微观结构显示,添加MoS2的Al2O3/TiC材料中的MoS2发生分解,基体中存在较多的气孔;添加BN的Al2O3/TiC材料中的BN与Al2O,反应生成AlN,造成大量裂纹的产生,致使材料的强度和硬度都大幅下降;Al2O3/TiC/CaF2陶瓷材料中的CaF2在烧结过程中没发生化学反应,复合材料晶粒大小均匀,基体组织成网状结构,有利于提高材料的强度. 相似文献
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Al2O3/TiC/CaF2自润滑陶瓷材料的研究 总被引:1,自引:0,他引:1
采用热压工艺制备了Al2O3/TiC/CaF2自润滑陶瓷材料,测量了其力学性能.结果表明,当CaF2含量为10%(质量分数,下同)时,Al2O3/TiC/CaF2自润滑陶瓷材料的强度和硬度最高,分别达到了589MPa和HV1537.其微观结构显示,Al2O3/TiC/CaF2自润滑陶瓷材料的晶粒大小均匀,基体组织成网状结构,有利于提高材料的强度.对Al2O3/TiC/CaF2自润滑陶瓷材料室温干摩擦下的摩擦磨损行为进行了研究,当CaF2含量为10%时,摩擦系数最低,约为0.28左右,CaF2含量为15%的陶瓷反而具有较大的摩擦系数,达到了0.32左右.研究表明,Al2O3/TiC/CaF2自润滑陶瓷材料能形成有效的减磨层,从而显著降低摩擦系数和磨损因子,具有一定的自润滑性能. 相似文献
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将Al2O3-TiC陶瓷材料与具有固体润滑特性的Al2O3-TiC-CaF2陶瓷材料进行叠层,通过真空热压烧结制备Al2O3-TiC/Al2O3-TiC-CaF2复合叠层陶瓷材料.在环盘式摩擦磨损试验机上进行摩擦磨损实验,研究该材料在不同载荷、转速条件下的摩擦系数和磨损率,分别用SEM及EDS观察材料磨损前后的微观形貌和分析其成分组成,研究其磨损机制.结果表明:在相同载荷条件下,Al2O3-TiC/Al2O3-TiC-CaF2复合叠层陶瓷材料的摩擦系数和磨损率随着转速的升高而下降,在相同转速条件下,其摩擦系数和磨损率随着载荷的增加而下降;Al2O3-TiC/Al2O3-TiC-CaF2复合叠层陶瓷材料的磨损机制主要是磨粒磨损和黏着磨损. 相似文献
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随着人们对陶瓷材料的需求和认识的提高,陶瓷材料的开发与应用已取得了迅速进展。就陶瓷材料的加工技术而言,一般都采用硬质砂轮进行切割和磨削,用磨料研磨和抛光就更普遍了。近年来,用金刚石刀具车削陶瓷材料,在特殊介质中焊接陶瓷等新技术的开发非常活跃。但对大型陶瓷和形状复杂的陶瓷件的加工,尤其是高精度的加工, 相似文献
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SiCp/Al composites have been widely used in many fields such as aerospace, automobile, advanced weapon system, etc. But this kind of material, especially with high volume fraction, is difficult to machine due to the reinforced particles existing in matrix, which has limited its further application. Rotary ultrasonic machining (RUM) has many excellent features and it has never been used to machine SiCp/Al composites. In order to improve the machinability and application of SiCp/Al composites, the rotary ultrasonic face grinding experiments of SiCp/Al composites reinforced with 45% volume SiC particles were carried out to investigate cutting force, surface quality, tool wear, and abrasive chip shapes. The experimental results indicate that ultrasonic vibration could reduce cutting force, surface roughness, surface defects, and increase plastic removal ratio. The cutting force could be lowered by an average of 13.86% and the surface roughness could be lowered by an average of 11.53%. The examined results of tool wear patterns suggest that tool wear is mainly caused by grain breakage and grain fall-off. Grinding wheel blockage and grinding burn were not observed in machining process. 相似文献
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Congfu Fang Zhen Yan Wenwen Deng Liangchi Zhang 《Materials and Manufacturing Processes》2019,34(7):791-799
Grinding is an important abrasive machining process in many manufacturing chains. In order to improve the material removal in the grinding of sapphire wafers, this study presents two brazed-diamond pellet (BDP) plates developed with different BDP surface textures, i.e., a non-grooved BDP plate and a grooved BDP plate. Their performances were tested in the coarse grinding of sapphire wafers. The surface topography, surface roughness, material removal rate (MRR) were comprehensively investigated. The experimental results show that sapphire is removed in its brittle mode. However, the grooved BDP plate can produce lower surface roughness under a higher MRR. The improvement in surface roughness is mainly due to the better coolant flowability and chip removal facilitated by the grooves. The higher MRR is partly due to the increased pressure in the sapphire-plate contact zone. It is found that the grooved BDP plate can increase MRR by about 45.7%. 相似文献
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Polishing of ceramic tiles 总被引:2,自引:0,他引:2
Grinding and polishing are important steps in the production of decorative vitreous ceramic tiles. Different combinations of finishing wheels and polishing wheels are tested to optimize their selection. The results show that the surface glossiness depends not only on the surface quality before machining, but also on the characteristics of the ceramic tiles as well as the performance of grinding and polishing wheels. The performance of the polishing wheel is the key for a good final surface quality. The surface glossiness after finishing must be above 20° in order to get higher polishing quality because finishing will limit the maximum surface glossiness by polishing. The optimized combination of grinding and polishing wheels for all the steps will achieve shorter machining times and better surface quality. No obvious relationships are found between the hardness of ceramic tiles and surface quality or the wear of grinding wheels; therefore, the hardness of the ceramic tile cannot be used for evaluating its machinability. 相似文献
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Nano finish grinding of brittle materials using electrolytic in-process dressing (ELID) technique 总被引:4,自引:0,他引:4
Recent developments in grinding have opened up new avenues for finishing of hard and brittle materials with nano-surface finish,
high tolerance and accuracy. Grinding with superabrasive wheels is an excellent way to produce ultraprecision surface finish.
However, superabrasive diamond grits need higher bonding strength while grinding, which metal-bonded grinding wheels can offer.
Truing and dressing of the wheels are major problems and they tend to glaze because of wheel loading. When grinding with superabrasive
wheels, wheel loading can be avoided by dressing periodically to obtain continuous grinding. Electrolytic inprocess dressing
(ELID) is the most suitable process for dressing metal-bonded grinding wheels during the grinding process. Nano-surface finish
can be achieved only when chip removal is done at the atomic level. Recent developments of ductile mode machining of hard
and brittle materials show that plastically deformed chip removal minimizes the subsurface damage of the workpiece. When chip
deformation takes place in the ductile regime, a defect-free nano-surface is possible and it completely eliminates the polishing
process. ELID is one of the processes used for atomic level metal removal and nano-surface finish. However, no proper and
detailed studies have been carried out to clarify the fundamental characteristics for making this process a robust one. Consequently,
an attempt has been made in this study to understand the fundamental characteristics of ELID grinding and their influence
on surface finish. 相似文献
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可加工Ce-ZrO2/CePO4陶瓷材料的裂纹扩展及加工损伤 总被引:1,自引:0,他引:1
对可加工Ce—ZrO2/CePO4陶瓷材料中裂纹扩展及加工损伤进行了研究。发现其与一般脆性陶瓷中裂纹扩展有所不同,由于CePO4的加入在基体中形成了弱界面,在荷载作用下弱界面处易形成微裂纹,并发生裂纹的偏转、分支和桥联等形式,使得材料中裂纹的扩展呈现不连续性。而且CePO4加入量对裂纹扩展和加工损伤具有较大的影响,加入量较小时裂纹扩展不连续性并不明显,加工损伤大,加工困难;加入量较大时裂纹呈发散状态,加工损伤小,但材料性能降低。 相似文献
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结构陶瓷磨削表面微裂纹的研究 总被引:6,自引:0,他引:6
结构陶瓷的磨削表面微裂纹是较常见和较危险的磨削损伤,本文应用压痕断裂力学。磨削表面热应务陶瓷微观结构的有关知识分析了结构陶瓷表面裂纹的形成机理、形状特征及奖表面的延伸,并对几种典型结构民磨削表面层的微观状态进行了大量的SEM观察,结果表明:(1)磨削微裂纹与陶瓷的断裂韧性K1C和显微硬度H之比、陶瓷的热特性及磨削工艺参数有关;(2)磨削微裂纹的 压痕效应径向裂纹、热裂纹、(3)细晶陶瓷多为穿晶裂纹 相似文献
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Grinding of ceramic‐metal‐compounds – finite element analysis simulation of the grinding process of hybrid stratified compounds In this paper, the subproject TP 8 “Grinding of ceramic‐metal‐compounds” is been introduced. An adapted grinding strategy should be created for the production of a ceramic‐cemented carbide compound drill. This aim should be obtained with experimental analysis and the use of finite element analysis to simulate the grinding process of ceramic‐cemented carbide compound drill. Furthermore a basic approach for simulating the grinding process of hybrid stratified compounds is been presented, which should be a basis for a finite element analysis simulation of a grinding process of ceramic‐cemented carbide compound drill. 相似文献
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B. P. Bandyopadhyay H. Ohmori I. Takahashi 《Materials and Manufacturing Processes》1996,11(5):789-801
Advanced structural ceramics, such as silicon nitride based materials, are of interest owing to their unique physical and mechanical properties. However the cost of grinding these ceramics, which is an integral part of their fabrication, is very high. Moreover, grinding can result in surface and sub-surface damage in the material and these defects can significantly reduce the strength and reliability of the finished components. Grinding damage is sensitive to grinding parameters. Two types of silicon nitride based ceramic materials were ground with Electrolytic In-Process Dressing (ELID) using different grit sized metal bonded diamond grinding wheels. With the application of ELID technology, mirror surface finish was realized with a #4000 mesh size wheel (average grain size = 4μm). Differences in ground surface topography caused by wheel grain size were analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The SEM and AFM studies reveal that material was predominantly removed in the ductile mode when ELID grinding was performed with a #4000 grit size wheel or finer. 相似文献