首页期刊导航|Key engineering materials
期刊信息/Journal information
Key engineering materials
Trans Tech Publications Ltd.
Key engineering materials

Trans Tech Publications Ltd.

半月刊

1013-9826

Key engineering materials/Journal Key engineering materials
正式出版
收录年代

    Current Status of Oxide Fibre-Reinforced Oxide Ceramic Matrix Composites for Gas Turbine Applications

    Cengiz Kaya
    1-4页
    查看更多>>摘要：Recent developments in the processing, understanding and mechanical/thermomechanical properties of oxide fibre reinforced oxide ceramic matrix composites for high temperature applications are reported. Two dimensional composite plates and uni-directional tubular composite (so called mini-composite) specimens are successfully manufactured and their microstructure, matrix/ fiber interface as well as mechanical properties are examined. It is shown that the microstructural variations, such as porosity size and interface between fibre and matrix determine the fracture behaviour and high temperature performance of the composites. The optimised components produced are considered to be suitable for gas turbine applications.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Fabrication of Textured β-Si_3N_4 and β-Sialon by Slip Casting in A Strong Magnetic Field and Reaction-Sintering

    Y. SakkaX. W. Zhu
    5-8页
    查看更多>>摘要：This paper reviews the most important results by the authors on the processing of textured β-Si_3N_4 and β-sialon by slip casting in a strong magnetic filed of 12 T and reaction-sintering. The a, b-axis textured β-Si_3N_4 and β-sialon have been obtained using the static magnetic field because of the magnetic susceptibility of X_(a, b) > X_c for β-Si_3N_4. However, the c-axis textured β-Si_3N_4 has also been successfully obtained using a rotating magnetic field. The β-Si_3N_4 crystal was found to exhibit substantially stronger orientation ability than the α-si_3N_4 crystal regardless of the Si_3N_4 raw powders. It reveals that the β-Si_3N_4 nuclei play a key role in the texture development in β-Si_3N_4/β-sialon.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Large Bulk Al_2O_3/ZrO_2 (Y_2O_3) Nanocrystalline Composites Prepared by Combustion Synthesis under High Gravity

    Zhongmin ZhaoLong ZhangChuanzeng PanQuan Yang...
    9-12页
    查看更多>>摘要：The large bulk Al_2O_3/ZrO_2 (Y_2O_3) eutectics were achieved by combustion synthesis in high-gravity field. With increasing high-gravity level, the matrix of eutectics transformed the rod-shaped colonies from the cellular ones, and the nanocrystalline microstructures came into existence as the high-gravity level was larger than 200g. The relative density, hardness, flexural strength and fracture toughness increased simultaneously with increasing high-gravity level, and reached the maximum values of 98.6%, 18.6GPa, 1248MPa and 15.6MPa·m~(1/2) respectively as the high-gravity level was 250g.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Ultra-high-hard Composites of TiC-TiB_2 Prepared by Combustion Synthesis under High Gravity

    Zhensheng QuQuan YangZhongmin ZhaoLong Zhang...
    13-16页
    查看更多>>摘要：The large-bulk solidified TiC-TiB_2 composites were prepared by combustion synthesis in high-gravity field. XRD, FESEM, SEM and EDS results showed that TiC-TiB_2 composites were mainly composed of TiC matrix in which a number of fine TiB_2 platelets were embedded, surrounded by the boundary regions consisting of (Cr, Ti) C_(0.63) carbides. The hardness, flexural strength and fracture toughness of TiC-TiB_2 composites measured 28.5GPa, 750±25MPa and 6.2±0.5MPa·m~(1/2). High hardness of the composites benefits from the absence of the intermediate borides and the achievement of stoichiometric TiC phases due to rapid solidification, whereas the achievement of high strength benefits the refinement and homogeneity of the microstructures due to rapid separation of liquid oxides in high-gravity field and rapid coupled growth of TiC and TiB_2 phases.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    A Study on the Porous Microstructure of Yakbone Bioceramic

    Zhou JieZhao WanyiQuan Guozheng
    17-20页
    查看更多>>摘要：Research on microstructure and behavior of natural biomaterials contributes to understanding the biomimetic design. Yakbone bioceramic's cross section with innumerable voids was observed via SEM approach, then a digital image processing technique was adopted to analyze the images. It is supposed that the pores can be classified into n series by different size level. A non-linear function between the pore size and series number got fitted which indicates a regression trend to zero as n rising to a large number. A non-linear convergent analysis of the function results in the porosity of porous microstructure of yakbone bioceramic. Furthermore, a plane helices characterization model was assumed to descript the multilevel voids distribution, then a series of helices parameters were designed for bionic yakbone porous microstructure with porosity tolerance of 2.5%. This parameter description of yakbone, a porous bioceramic with high strength and light weight, contributes to further research on the relationships between mechanical property and microstructure.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Effect of Microstructure on Removal Mechanism of Solid State Sintered Silicon Carbide in Polishing Procedure

    Jianqin GaoZhengren HuangJian ChenGuilin Liu...
    21-23页
    查看更多>>摘要：Solid state sintered silicon carbide (S-SiC) ceramic is one of the top optical materials for high space reliability and other excellent properties. Two microstructures were produced by sintering under different conditions. The effects of microstructure on removal rates of SiC ceramics during polishing processes were studied. The material removal mechanisms during polishing were analysed and modeled. With the increase of the aspect ratio and grain diameter size during polishing, grain pull-out is more difficult in elongated grains than in exquiaxed grains. The SiC ceramic with high hardness has high removal resistance leading to get bad surface quality under the same mechanical procedure. The samples with elongated microstructure have low hardness and surface toughness.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Densification and Mechanical Properties of B_4C Based Composites Sintered by Reaction Hot-pressing

    Wang GuofengZhang JihongZhang ChunpingZhang Kaifeng...
    24-27页
    查看更多>>摘要：Boron carbide (B_4C) possesses unique physical and thermal properties. In this paper, B_4C based composites toughened by TiB_2 were fabricated by in-situ reaction sintering with the original microcrystalline powders B_4C, TiO_2 and glucose. The influences of sintering temperature and content of TiO_2 on the sintering behavior and mechanical properties were investigated. (TiB_2, Al_2O_3)/B_4C and (TiB_2,SiC)/B_4C composites with almost fully dense were fabricated by using additives of Al_2O_3 and Si powders and sintering at 1950℃ and 1900℃, the fracture toughness of composites reach to 7.09 and 6.35 MPa·m~(1/2) respectively. The analysis of microstructure shows that the main toughen mechanism is the crack deflection due to the existence of residual stress.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Mechanical and Tribological Properties of 3D Carbon Fiber Reinforced SiC Composites Prepared by Liquid Silicon Infiltration

    Haijun ZhouShaoming DongXiangyu ZhangJinshan Yang...
    28-32页
    查看更多>>摘要：C/SiC composites were prepared by liquid silicon infiltration process, and their microstructure, mechanical and tribological properties were studied in this paper. The results showed that the composites demonstrated non-catastrophic fracture behavior with long fibers pulled out and about 115 MPa flexural strength. The stability of coefficient of friction (COF) was improved and wear rate demonstrated a linear variation with the increasing of rotation speeds. However, wear rate exhibited a higher value (～3.6μg/m) under a higher load (～150 N), even though the COF curves for C/SiC composites showed no significant changes.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Structure and Performance of Self-reactive Spray Formed Ti(C,N)-TiB_2 Multi-phased Ceramic Materials

    J. J. WangH. W. LiuW. B. HuJ. H. Wen...
    33-36页
    查看更多>>摘要：Based on the Ti-B_4C-sucrose(precursor of carbon) -5wt.% Al sprayed system, the self-reactive spray formed multi-phased structural ceramic preforms tests were done. And the organization, structure and performances of the products were studied. The results show that the products are composed of continuous matrix phase TiC_(0.3)N_(0.7), dispersed micro/nanometric rodlike grains TiB_2, some of Al_2O_3, pores and intermetallic phase Ti_3Al which is hard to identify by SEM. Aluminum is benefit to improve organization, structure and performances of the products. The average density of the products is 97.7%, the Vickers hardness is 20.6GPa, and the flexural strength is 425MPa. There are crack deflection and grain bridging toughening mechanisms owing to the rodlike grains of TiB_2 in the products, which makes their fracture toughness is as high as 7.3MPa·m~(1/2).
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Microstructure and Performance of the Hot-Pressed Silicon Nitride Ceramics with Lu_2O_3 Additives

    Tong JianfengChen DarningLi BaoweiHuanghao...
    37-41页
    查看更多>>摘要：The influence of Lu_2O_3 on phase transformation and seeds morphology was investigated. The result showed that the β-Si_3N_4 seeds with up to 95% β phase content could be obtained with 2wt% Lu_2O_3 as the additive content under 1750℃ for two hours. The microstructure and mechanical properties of hot-pressed Si_3N_4 ceramics, using 9wt.% of Lu_2O_3 additives were investigated by the means of MTS measurements and Vickers indentation crack size measurements, as well as XRD and SEM. It was known that the high fracture toughness of Si_3N_4 ceramics was attributed to the rodlike morphology of β-Si_3N_4 grains. And the reinforcement effect and mechanism of β-Si_3N_4 seed were studied. It was found that the grain size and its distribution influence the property and microstructure of Si_3N_4 ceramics, namely, the relative narrow distribution of grain diameter in some extent and relative wide range of bimodal distribution of grain aspect ratio could improve the property of Si_3N_4 ceramics. The improvement in the fracture toughness with the amount of additive was mainly attributed to elongated grain growth during the sintering process.The high temperature properties of self-reinforced Si_3N_4 with different additives were studied. By this method, self-reinforced Si_3N_4 ceramics with an increment of 10～20 percent of fracture toughness was successfully fabricated.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd