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提出了一种新的低成本自反应喷射成形技术,制备出TiC-TiB2复合陶瓷材料坯件,研究了材料的组织结构对性能的影响.结果表明,反应喷射成形坯件的组织具有快速凝固特征,主要由浅灰色连续基体相TiC0.3N0.7、尺寸为100nm-1μm呈柱状分布的黑色颗粒TiB2,少量分布于基体相边界的白色相组织TiO2以及少量黑色的不规则孔洞四部分组成.喷射沉积坯件的孔隙率为2.3%,显微硬度为2029HV0.2,断裂韧性为6.0 MPa·m1/2.向喷射体系中添加20%(质量分数)的Al-Ni合金使材料的孔隙率下降到1.7%,断裂韧性提高到7.7 MPa·m1/2,显微硬度下降到1259HV0.2.由于自反应喷射成形坯件的晶粒细小,其断裂韧性高于反应烧结与自蔓延高温合成方法制备的TiC-TiB2复合陶瓷材料. 相似文献
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为提高陶瓷喷砂嘴抗冲蚀磨损能力,缓解喷嘴入口、出口的高应力状态,采用热压烧结工艺制备了Al2O3+(W,Ti)C/Al2O3+TiC三层对称型叠层陶瓷材料及叠层陶瓷喷嘴.研究结果表明:叠层陶瓷材料表层较之相应单一材料而言,具有更高的硬度和断裂韧性;在相同的冲蚀磨损条件下,叠层陶瓷喷嘴的抗冲蚀磨损性能较非叠层陶瓷喷嘴有显著的提高;试验分析叠层陶瓷喷嘴的最佳层厚比为2.此外,采用有限元法对叠层陶瓷喷嘴在制备过程中的残余应力进行了理论计算,给出了叠层陶瓷喷嘴中残余应力与层厚比的关系.研究表明,残余压应力的存在,细化了晶粒,提高了叠层材料表层的硬度和断裂韧性,是叠层陶瓷喷嘴其抗冲蚀磨损能力提高的原因.理论分析最佳层厚比也为2,理论分析与试验结果相互印证. 相似文献
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为提高ZTA陶瓷在口腔临床应用中的性能,本实验以高分子聚合物作为粘结剂,羧甲基纤维素为骨架制备口腔托槽用ZTA陶瓷材料.通过探究粉体固含量、羧甲基纤维素(CMC)用量、丙烯酸(AA)用量、过硫酸铵(APS)用量四个因素对ZTA陶瓷材料的抗弯强度、断裂韧性的影响规律,制备最优工艺水平下的ZTA陶瓷并进行性能测试.结果表明:CMC加入量为0.85 g、APS加入量为0.8 g、AA加入量为7.5 mL、Al2 O3加入量为110 g、ZrO2加入量为33 g时,ZTA陶瓷材料的抗弯强度为222.3 MPa,断裂韧性为8.67 MPa·m1/2,相对致密度为0.977,抗剪切强度在6.06~6.93 MPa之间,满足临床需求. 相似文献
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为提高陶瓷喷砂嘴抗冲蚀磨损能力,缓解喷嘴入口、出口的高应力状态,采用热压烧结工艺制备了Al2O3+(W,Ti)C/Al2O3+TiC三层对称型叠层陶瓷材料及叠层陶瓷喷嘴.研究结果表明:叠层陶瓷材料表层较之相应单一材料而言,具有更高的硬度和断裂韧性;在相同的冲蚀磨损条件下,叠层陶瓷喷嘴的抗冲蚀磨损性能较非叠层陶瓷喷嘴有显著的提高;试验分析叠层陶瓷喷嘴的最佳层厚比为2.此外,采用有限元法对叠层陶瓷喷嘴在制备过程中的残余应力进行了理论计算,给出了叠层陶瓷喷嘴中残余应力与层厚比的关系.研究表明,残余压应力的存在,细化了晶粒,提高了叠层材料表层的硬度和断裂韧性,是叠层陶瓷喷嘴其抗冲蚀磨损能力提高的原因.理论分析最佳层厚比也为2,理论分析与试验结果相互印证. 相似文献
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由于陶瓷材料在工程使用中所呈现的脆性问题日益引起人们的关注,脆性直接影响陶瓷材料的抗裂性能,目前由于有关陶瓷抗裂性能指标测量-断裂韧性的测量方法存在误差很大、可操作性不高等不足,已经影响和制约了陶瓷性能的研究和发展;本文基于陶瓷材料疲劳损伤三阶段理论,提出了陶瓷材料动态断裂韧性的概念,并通过实验测量出陶瓷材料在动态载荷作用下裂纹萌生之前的韧性变化过程,有效区别在相同烧结温度下堇青石、莫来石陶瓷的动态韧性的差异,为陶瓷材料的韧性测量提出了一种新方法。 相似文献
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采用真空热压烧结工艺制备了石墨烯(GNPs)和纳米Al2O3增韧的Ti(C,N)基金属陶瓷复合刀具材料(TAG)。研究了GNPs和纳米Al2O3对复合陶瓷材料微观结构、力学性能和摩擦磨损性能的影响。研究表明,GNPs和纳米Al2O3的添加对复合陶瓷材料的力学性能有明显的提高,当GNPs和纳米Al2O3含量(质量分数)为1%和5%时,复合刀具陶瓷材料(TA5G1)综合力学性能最优,其硬度、抗弯强度和断裂韧性分别为21.50 GPa、810.80 MPa和10.51 MPa·m1/2。研究了复合刀具材料的摩擦磨损性能和磨损机理,研究结果表明,在TAG复合刀具材料中,TA5G1的摩擦磨损性能最优,其摩擦系数和磨损率分别为0.338和4.921×10-6 mm3/(N·m),复合刀具材料的主要磨损形式为磨粒磨损和黏着磨损。 相似文献
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D.L. Davidson 《International Journal of Fracture》1999,96(4):361-372
The failure modes of particulate reinforced metallic alloys are reviewed with special emphasis on in situ intermetallic particle
reinforced niobium alloys, but information derived from ceramic reinforced aluminum alloys is also included. Constraint of
plastic deformation by particles is emphasized as one of two very important factors in controlling fracture behavior. The
other factor is particle fracture toughness. Models are proposed for describing the fracture toughness, from which several
methods of enhancing toughness are envisioned. This modeling of fracture toughness is intended to help optimize the design
and processing of these materials for enhanced fracture resistance.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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基于虚拟裂纹闭合法对传统压痕法测试陶瓷材料断裂韧性的数值模型进行计算,以此为基础,分析比较传统压痕法的几种典型公式识别陶瓷材料断裂韧性的测试误差和所测材料的适用范围。结果表明:传统压痕法的Anstis公式较Evans公式,Lawn公式,JISR公式和Niihara公式,在材料比功0.3≤We/Wt≤0.45时所测断裂韧性值与理论计算值较为接近,其最大误差为12.9%,测试结果相对准确;当0.45We/Wt≤0.7时,传统压痕法对陶瓷材料断裂韧性的测试误差随比功增加迅速增大,特别是当We/Wt=0.7时,Anstis公式,Evans公式,Lawn公式,JISR公式和Niihara公式所测断裂韧性值与理论计算值的最大误差分别为70%,148.5%,48.8%,98.7%和166.6%,在此材料比功范围内传统压痕法所测断裂韧性值误差较大。 相似文献
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The role of interface on the fracture toughness of ceramic glass reinforced with metallic ribbon was investigated. A strong interfacial bonding strength is essential for load transfer between the matrix and ribbon, and for utilization of the ductility of the reinforcement. However, weak interfacial bonding is considered to be important so that ribbon pull-out can improve the toughness of brittle ceramic matrix composites. The main aim of the present study is to carry out interface design to optimize mechanical properties of brittle ceramic matrix composites reinforced with ductile metallic ribbons. 相似文献
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Chongzhen Du Chuanzhen Huang Shijie Li Hanlian Liu 《Advanced Engineering Materials》2023,25(20):2300564
The design of the lamination structure based on bionic shell pearl layer is a successful method for toughening ceramics. Lamination with strong bonding interfaces is used to improve the mechanical property and low fracture toughness of ceramic cutting tools. Based on the idea of demand–design–preparation–analysis–failure, the development and research progress of laminated ceramic tools are reviewed herein. The research status of design, interlayer diffusion reaction, residual stress, toughening mechanism, and crack propagation path of the biomimetic laminated ceramic composite tool materials is mainly introduced. The major topics of current research include the creation of material systems, the evolution of microstructure, and the assessment of macroscopic mechanical properties. The entire mechanical properties of laminated ceramic tools are significantly influenced by the multicomposition design of the ceramic material system and the optimization design of structural parameters of layer number and layer thickness ratio. However, the research on the practical cutting application of laminated ceramic tools is limited. Cutting tool wear characteristics vary between laminated and homogeneous ceramic tools. The development of useful laminated ceramic cutting tools can greatly benefit from the study on failure mechanisms of laminated ceramic tools. 相似文献
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Clément J Torres P Gil FJ Planell JA Terradas R Martinez S 《Journal of materials science. Materials in medicine》1999,10(7):437-441
Indentation tests are commonly used for the evaluation of fracture toughness of brittle materials, particularly glasses and ceramics, because this technique requires only a small polished area on the specimen surface from which a large number of data points can be generated rapidly. However, a wide variety of equations for the calculation of fracture toughness of ceramic materials by means of Vickers indentation are available. Such equations are obtained phenomenologically and their parameters adjusted in such a way that the KIC values obtained are in good agreement with those obtained by conventional methods. This is the reason why it is necessary to check which type of equation reproduces more accurately the results obtained by means of conventional methods for the material which is going to be investigated. In the present work seven different fracture toughness equations widely used in glass and ceramic studies are considered and the results are compared with those obtained by conventional methods, such as single-edge notch beam (SENB) specimens tested in three-point bending. The role played by the applied indentation load is considered. © 1999 Kluwer Academic Publishers 相似文献
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Boron carbide-silicon carbide ceramic composites are very promising armor materials because they are intrinsically very hard.
However, their fracture toughness is not very high. Their ballistic performance could be significantly increased if the brittleness
of these materials could be decreased. Here we report development of boron carbide-silicon carbide layered ceramics with controlled
compressive and tensile stresses in separate layers. Such B4C-SiC laminates with strong interfaces can provide high apparent fracture toughness and damage tolerance along with high protection
capabilities.
The theory of heterogeneous layered systems was used to develop optimal design parameters allowing the evaluation and maximization
of apparent fracture toughness. The layered composites were designed in a way to achieve high compressive residual stresses
in thin B4C-SiC based layers and low tensile residuals stresses in thick B4C layers. The residual stresses were controlled by the phase composition of layers and the layers thickness. The estimated
apparent fracture toughness was calculated for both three layered and nine layered composites. B4C-30 wt%SiC/B4C laminates were made based on the optimized design for high apparent fracture toughness. Processing of laminates involved
preprocessing of powders, forming green tapes and hot pressing. Work is in progress to measure fracture toughness of laminates,
as well as their strength, hardness and the ballistic performance. 相似文献
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Dong-Joo Lee 《Journal of Materials Science》1995,30(18):4617-4622
A new and simple method to study the change in crack resistance during the process of crack growth in ceramic materials has been developed. The method is based on using the chevron-notched short-bar test which is generally accepted as a convenient method for measuring fracture toughness. The simple modification described here allows one to measure fracture toughness using the assumption that fracture toughness changes in the process of crack growth (presence of crack resistance curve, or R-curve). This method presents many advantages, especially the long stable crack growth under mode I fracture specimen and plane strain, small specimen size and no need of pre-cracking for measuring R-curve behaviour in ceramic materials. 相似文献
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D. Yu. Ostrovoi G. A. Gogotsi S. A. Gorban’ S. P. Oshkaderov V. I. Stepkin A. N. Bobokal 《Strength of Materials》2005,37(3):323-330
The strength in biaxial flexure and the fracture toughness on indentation of the specimens of ceramic materials for the coverage of metal-ceramic prostheses were studied. The strength was established to be mainly determined by their microstructure and sintering conditions. Comparative studies demonstrated that Ultropaline and VITA OMEGA 900 ceramic compositions exhibited more uniform distribution of leucite microcrystals and higher strength and fracture toughness than Duceram Plus and IPS Classic materials.__________Translated from Problemy Prochnosti, No. 3, pp. 128 – 139, May – June, 2005. 相似文献