Ti3SiC2/4SiC复相陶瓷的高温力学性能研究

为了进一步了解Ti3SiC2/nSiC复合材料优良的综合性能,特别是其高温力学性能,本文以热等静压原位合成技术制备的Ti3SiC2/4SiC复相陶瓷为试验材料,对其高温拉伸和高温弯曲行为进行研究。结果表明:Ti3SiC2/4SiC复相陶瓷的高温抗拉强度比室温抗拉强度高;Ti3SiC2/4SiC复相陶瓷的高温抗弯强度在900℃出现一极大值,1000℃后具有好的高温塑性。     

Ti3SiC2基复合材料的研究现状及发展趋势

Ti3SiC2及Ti3SiC2复合材料是材料研究中的热点领域。介绍了Ti3SiC2基复合材料的体系选择、制备技术及其研究现状。指出了进一步研究应该解决的问题和未来的发展前景。最近，作者采用热压烧结工艺制备高纯致密Ti3SiC2/TiB2复合材料。     

Ti3SiC2陶瓷的制备及性能研究

层状陶瓷材料Ti,SiC2结合了金属和陶瓷的许多优异性质,既具有与金属相似的良好的导热、导电性,良好的可加工性,相对柔软,抗热震性好,可塑性变形等性能,同时又具有与陶瓷相似的抗氧化、耐腐蚀、耐高温等特性;并且还有很好的自润滑性和超低磨擦系数,被认为在许多领域有着广泛的应用前景。     

Short SiC fiber/Ti3SiC2 MAX phase composites: Fabrication and creep evaluation

The compressive creep of silicon carbide fiber reinforced Ti₃SiC₂ MAX phase with both fine and coarse microstructure was investigated in the temperature range of 1000-1300°C. Comparison of only steady-state creep was done to understand the response of fabricated composite materials toward creep deformation. It was demonstrated that the fibers are more effective in reducing the creep rates for the coarse microstructure by an increase in activation energy compared to the variant with a finer microstructure, being partly a result of the enhanced creep rates for the microstructure with larger grain size. Grain boundary sliding along with fiber fracture appears to be the main creep mechanism for most of the tested temperature range. However, there are indications for a changed creep mechanism for the fine microstructure for the lowest testing temperature. Local pores are formed to accommodate differences in strain related to creeping matrix and predominantly elastically deformed fibers during creep. Microstructural analysis was done on the material before and after creep to understand the deformation mechanics.     

放电等离子烧结制备Ti/Al2O3复合材料

Ti基金属复合材料是一种新型高温结构材料.本文利用放电等离子烧结技术,在温度1250℃、压力30MPa、真空度6Pa,保温时间10min条件下,制备了相对致密度较高的Ti/Al2O3复合材料.借助XRD,SEM,EDS等测试手段对该复合材料的物相组成、界面反应、微观结构以及致密度进行了观察与分析.结果表明:利用SPS技术制备Ti/Al2O3的复合材料,晶粒细小且分布均匀,结构致密、2相之间结合状态良好,相对致密度随材料中陶瓷相含量的增多而有所降低.Ti,Al2O32相之间无明显界面化学反应发生.     

Ti3SiC2陶瓷粉末的制备

新型层状陶瓷材料Ti3SiC2集金属和陶瓷的优良性能于一身,如良好的导电导热性、耐氧化、耐热震、高弹性模量、高断裂韧性等,在高温结构陶瓷、电刷和电极材料、可加工陶瓷材料、自润滑材料等领域有着广泛的应用前景。本文综合介绍了Ti3SiC2粉末制备的研究进展。此外,作者以Ti／Si／C／Al元素粉为原料,采用无压烧结的方法制备出纯度较高的Ti3SiC2陶瓷粉末,为Ti3SiC2基复合材料的发展开辟了一条新途径。     

Fabrication of Ti3SiC2-Ti4SiC3-SiC ceramic composites through carbosilicothermic reduction of TiO2

Dense Ti₃SiC₂-SiC, Ti₄SiC₃-SiC, and Ti₃SiC₂-Ti₄SiC₃-SiC ceramic composites were fabricated through carbosilicothermic reduction of TiO₂ under vacuum, followed by hot pressing of the as-synthesized products under 25 MPa at 1600°C. In the reduction step, SiC either alone or in combination with elemental Si was used as a reductant. A one-third excess of SiC was added in the reaction mixtures in order to ensure the presence of approximately 30 vol.% SiC in the products of synthesis. During the hot pressing step, the samples that contained Ti₃SiC₂ showed better densification compared to those containing Ti₄SiC₃. The obtained composites exhibited the strength properties typical of coarse-grained MAX-phase ceramics. The flexural strength values of 424 and 321 MPa were achieved in Ti₃SiC₂-SiC, and Ti₃SiC₂-Ti₄SiC₃-SiC composites, respectively. The fracture toughness values were 5.7 MPa·m^1/2.     

三元导电陶瓷Ti3SiC2的研究进展

层状结构的Ti3SiC2属六方晶体结构,结合了金属和陶瓷的许多优异性能,如良好的导热和导电性能,优良的可加工性,耐氧化、耐化学腐蚀,优异的抗热震性,良好的自润滑性等,具有广阔的应用前景.本文介绍了Ti3SiC2的结构和性能,对其制备方法及应用进行了阐述.     

Ti3SiC2 Reinforced ZA27 Alloy Composites with Enhanced Mechanical Properties

This work reports the fabrication and mechanical properties of Ti₃SiC₂ reinforced Zn‐27 wt. % Al alloy (denoted as ZA27). A total of 10–40 vol. % Ti₃SiC₂ reinforced ZA27 alloy composites were synthesized by hot pressing mechanically alloyed mixtures of Ti₃SiC₂ and ZA27 powders. Among the fabricated composites, 20 vol. % Ti₃SiC₂/ZA27 composite possesses the highest room temperature tensile strength, bending strength and Vickers hardness of 339 MPa, 593 MPa, and 1.13 GPa, respectively. The improved mechanical properties of the 20 vol. % Ti₃SiC₂/ZA27 composite are mainly attributed to the effects of fine‐grain strengthening and dispersion strengthening.     

Ti3SiC2及其复合材料的研究现状及发展趋势

介绍了Ti3SiC2陶瓷材料的微观结构与性能,认为该材料良好的综合性能有望解决陶瓷材料的脆性问题.并概述了Ti3SiC2及Ti3SiC2基复合材料各种制备方法的特点和研究状况、应用前景和发展趋势.     

Microstructure and Mechanical Properties of (TiB2 + SiC) Reinforced Ti3SiC2 Composites Synthesized by In Situ Hot Pressing

Fully dense (TiB₂ + SiC) reinforced Ti₃SiC₂ composites with 15 vol% TiB₂ and 0–15 vol% SiC were designed and synthesized by in situ reaction hot pressing. The increase in SiC content promoted densification and significantly inhibited the growth of Ti₃SiC₂ grains. The in situ incorporated TiB₂ and SiC reinforcements showed columnar and equiaxed grains, respectively, providing a strengthening–toughening effect by the synergistic action of particulate reinforcement, grain's pulling out, “self‐reinforcement,” crack deflection, and grain refining. A maximum bending strength of 881 MPa and a fracture toughness of 9.24 MPam^1/2 were obtained at 10 vol% SiC. The Vickers hardness of the composites increased monotonously from 9.6 to 12.5 GPa.     

Ti3SiC2/SiC复合材料的抗高温氧化性研究

采用反应热压烧结法制备Ti3 SiC2/SiC复合材料,针对不同SiC含量的Ti3 SiC2/SiC复合材料在1100 ～ 1500℃下恒温氧化20h的氧化行为进行了研究.结果表明:(1)适量SiC的引入能有效的提高Ti3 SiC2/SiC复合材料的抗高温氧化性能;(2)复合材料的氧化膜分内外两层,外层成分为TiO2,逐渐向内层过渡为TiO2和SiO2的混合物.     

微波烧结制备Ti3SiC2-金刚石复合材料的显微形貌及界面反应机理

采用Ti3SiC2粉体和金刚石粉体为原料,通过微波烧结制备Ti3SiC2结合剂金刚石复合材料,研究金刚石的含量和粒度对该复合材料的物相组成与显微形貌的影响.结果表明,通过高温微波烧结Ti3SiC2结合剂金刚石复合材料,金刚石表面会形成不同的涂层,从而与基体结合剂结合良好.金刚石的粒度和含量对复合材料中基体组成和金刚石的表面涂层状态有显著影响.烧结过程中,金刚石会不同程度的影响Ti3SiC2的分解.Ti3SiC2分解后生成Si与TiC.当金刚石含量相同(10％)、粒度较粗(30/40)时,金刚石表面会形成钛硅相与SiC涂层组织;基体的主相为Ti3SiC2、钛硅相与SiC.当金刚石粒度较细(W20)时,金刚石表面的C元素充分地与Si反应生成SiC涂层,基体主相变成TiC和Ti3SiC2.当金刚石粒度适中(120/140目与170/200目)时,基体的主相为Ti3SiC2.选取金刚石粒度为170/200目、金刚石含量较低时(5％与10％),基体的组成为Ti3SiC2与少量的SiC.金刚石含量较高时(20％与30％),基体的组成为Ti3SiC2与少量的TiC和SiC.各试样中金刚石表面都会形成钛硅相与SiC涂层组织.     

层状陶瓷Ti3SiC2的研究现状

新型层状陶瓷Ti3SiC2兼有金属和陶瓷的许多优良性能,具有高的热导率和电导率,易加工,同时具有良好的抗热震性、抗氧化性和高温稳定性.在高温结构陶瓷、电极材料、可加工陶瓷材料、自润滑材料等领域的应用有着很好的前景.本文综合评述了Ti3SiC2的性能、制备技术及应用等.     

Ti3SiC2结合刚玉材料的制备及性能研究

以板状刚玉为骨料,两种原料体系:TiC/Ti/Si,TiC/Ti/SiC作基质相,酚醛树脂作结合剂,在氩气保护下于1350～ 1550℃制备Ti3SiC2结合刚玉材料.研究了原料体系和烧成温度对其相组成、显微结构及常温物理性能的影响.结果表明:两种原料体系制备所得Ti3SiC2结合刚玉材料的相组成均为Al2O3,Ti3SiC2和TiC.两种原料体系在1350-1400℃合成材料耐压强度较高;随着烧成温度升高,其耐压强度减小.其中,Ti3SiC2结合刚玉材料采用体系TiC/Ti/Si,在1400℃烧结6h获得最佳综合性能:基质相中Ti3SiC2含量达到64％,耐压强度为65 MPa.     

可加工陶瓷Ti3SiC2的合成和性能

可加工的Ti3SiC2陶瓷属于六方晶体结构。空间群为R63／mmc。它有许多独特的优良性能。如很好的导电、导热能力。高温延展性、抗热震,高强度。抗氧化。耐腐蚀。超低摩擦性。良好的自润滑性等。制备该化合物的方法主要有CVD,SHS,HP/HIP等方法。作者以元素粉为原料。用等离子放电烧结(SPS)方法成功地制备了高纯的Ti3SiC2陶瓷。     

无压烧结制备Al2O3/SiC纳米复合陶瓷

用沉淀法包裹微米级SiC颗粒，通过常压、埋烧制备Al2O3／SiC纳米复合陶瓷。通过XRD、TG和SEM等分析了煅烧和烧结过程中相组成的变化、烧成收缩和显微结构。结果表明：利用SiC粉埋烧及碳粉制造还原气氛，含8wt％SiC(平均粒径为5mm)的复合粉末经800℃煅烧、成型，试样于1550℃，2h烧结，可制备Al2O3／SiC纳米复合陶瓷，其相对体积密度达95．2％，在烧结过程中由SiC氧化形成的无定形SiO2及与基质氧化铝反应形成的莫来石前躯体可大大促进烧结。     

热压烧结工艺制备Ti2AlC/Ti3AlC2陶瓷材料

以Ti,Al,C为原料,采用热压工艺制备出相组成为Ti2AlC/Ti3AlC2块体材料,合成材料的X—射线衍射和扫描电镜(SEM)分析的结果表明：当烧结温度为1400℃时,材料中的主晶相为Ti2AlC,大小为10μm的板状多晶体;而在1500℃的温度下烧结所得材料的主晶相为Ti3AlC2,其板状多晶体的晶粒尺寸平均约为20μm。     

Compressive creep of SiC whisker/Ti3SiC2 composites at high temperature in air

The compressive creep of a SiC whisker (SiC_w) reinforced Ti₃SiC₂ MAX phase-based ceramic matrix composites (CMCs) was studied in the temperature range 1100-1300°C in air for a stress range 20-120 MPa. Ti₃SiC₂ containing 0, 10, and 20 vol% of SiC_w was sintered by spark plasma sintering (SPS) for subsequent creep tests. The creep rate of Ti₃SiC₂ decreased by around two orders of magnitude with every additional 10 vol% of SiC_w. The main creep mechanisms of monolithic Ti₃SiC₂ and the 10% CMCs appeared to be the same, whereas for the 20% material, a different mechanism is indicated by changes in stress exponents. The creep rates of 20% composites tend to converge to that of 10% at higher stress. Viscoplastic and viscoelastic creep is believed to be the deformation mechanism for the CMCs, whereas monolithic Ti₃SiC₂ might have undergone only dislocation-based deformation. The rate controlling creep is believed to be dislocation based for all the materials which is also supported by similar activation energies in the range 650-700 kJ/mol.     

High temperature interfacial phase stability of a Mo/Ti3SiC2 laminated composite

A Mo/Ti₃SiC₂ laminated composite is prepared by spark plasma sintering at 1300 °C under a pressure of 50 MPa. Al powder is used as sintering aid to assist the formation of Ti₃SiC₂. The fabricated composites were annealed at 800, 1000 and 1150 °C under vacuum for 5, 10, 20 and 40 h to study the composite's interfacial phase stability at high temperature. Three interfacial layers, namely Mo₂C layer, AlMoSi layer and Ti₅Si₃ solid solution layer are formed during sintering. Experimental results show that the Mo/Ti₃SiC₂ layered composite prepared in this study has good interfacial phase stability up to at least 1000 °C and the growth of the interfacial layer does not show strong dependence on annealing time. However, after being exposed to 1150 °C for 10 h, cracks formed at the interface.