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热处理过程中SiCP/2024Al复合材料的热应力分析 总被引:2,自引:1,他引:2
为研究热处理过程中SiCP/2024Al复合材料的热应力的变化规律,及热处理工艺对SiCP/2024Al复合材料热残余应力的影响,利用Marc有限元软件对淬火和冷热循环热处理过程中的SiCP/2024Al复合材料的热应力进行了数值模拟.研究结果表明:热处理过程中,颗粒和基体的界面附近会产生很大的热应力场,并且在SiC颗粒的尖角处产生热应力集中;经淬火处理后的SiCP/2024Al复合材料的热残余应力与基体的屈服强度接近,但经过冷热循环处理后的SiCP/2024Al复合材料中的热残余应力明显降低. 相似文献
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烧结温度对Cf/SiC复合材料结构及性能的影响 总被引:1,自引:0,他引:1
以碳纤维为增强体, 热压烧结制备了Cf/SiC复合材料, 研究了烧结温度对Cf/SiC复合材料密度、结构及性能的影响. 研究发现: 提高烧结温度能够促进Cf/SiC复合材料的致密度; 当烧结温度低于1850℃时, 升高烧结温度, 复合材料的强度和断裂韧性也随之提高. 当烧结温度为1850℃时, 复合材料的性能最优, 弯曲强度达500.1MPa, 断裂韧性为16.9MPa·m 1/2. 当烧结温度达到1880℃时, 复合材料性能反而下降. 相似文献
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《材料研究学报》2017,(8)
采用常压烧结工艺在1700℃保温2 h制备了Si C/h-BN复相陶瓷,在真空条件下使用硅溶胶和酚醛树脂溶液对烧结后试样进行交替循环浸渍,并在1450℃保温1 h进行热解处理,对比研究了浸渍热解处理前后复相陶瓷的致密度、抗弯强度和Vickers硬度的变化,并讨论了复相陶瓷的强化机制。结果表明:Si C/h-BN陶瓷的致密度和力学性能在浸渍热处理后均得到显著的改善,其中Si C/20wt.%h-BN的相对密度从69.7%提高到74.9%,而抗弯强度提高了约1.5倍。浸渍热处理后形成了细小纳米态的Si C颗粒,相互交联沉积在孔隙界面,使裂纹沿界面扩展的阻力显著增加,从而提高了复合材料的力学性能。 相似文献
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将h-BN加入到MVQ和EVA混合物中制备导热绝缘h-BN/MVQ/EVA复合材料,SEM结果表明h-BN选择性分布在EVA,与杨氏方程理论一致.h-BN/MVQ/EVA复合材料中的双逾渗效应,有助于力学性能和导热性能的提升.h-BN/MVQ/EVA复合材料的热导率与h-BN含量和MVQ/EVA比值有关.当EVA质量分数为30%时,h-BN/MVQ/EVA复合材料热导率的相对值最大.h-BN/MVQ/EVA复合材料的拉伸强度和断裂伸长率与EVA含量有关,随着EVA和h-BN含量的增加,复合材料的介电常数降低. 相似文献
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h-BN/Si3N4陶瓷复合材料的断裂行为及断裂韧性 总被引:1,自引:0,他引:1
以亚微米级α-Si3N4和h-BN粉末为原料,Y2O3-Al2O3为助烧剂,采用热压烧结制备了h-BN/Si3N4陶瓷复合材料.研究3h-BN含量对h-BN/Si3N4陶瓷复合材料断裂韧性及其断裂行为的影响.结果表明:随着h-BN含量增加,柱状β-Si3N4晶粒的直径和长径比均下降;未加h-BN时,β-Si3N4陶瓷以沿晶断裂为主,添加体积含量为6%和8%的h-BN后,复合材料出现明显的沿晶和穿晶断裂,而添加10%h-BN的陶瓷复合材料则以沿晶断裂为主.随着h-BN含量增加,h-BN/Si3N4陶瓷复合材料的断裂韧性下降,但由于h-BN颗粒对裂纹扩展的影响,因而其下降程度不大. 相似文献
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Ning ZHANG Hongqiang RU Xudong SUN Qingkui CAI School of Materials Metallurgy Northeastern University Shenyang China Materials Department Shenyang University Shenyang China 《材料科学技术学报》2004,20(3):323-326
The α-SiC in 0.5μm size powders were coated with Al_2O_3 and Y_2O_3 by a coprecipitation coating (CPC) method forfabrication of SiC/YAG composites. The same powder preparation was carried out by conventional mechanical mixing(MM) method for comparison. Two kinds of SiC/YAG composites were manufactured by pressureless sintering usingthe different powders, named CPC composite and MM composite thereafter respectively. It is shown that the CPCcomposite has the advantages of homogeneous distribution of YAG phase and of being sintered to high density ata low temperature, 100℃ lower than that of MM composite. The strength (573 MPa) and hardness (23.3 GPa) ofthe CPC composite are significantly higher than those (323 MPa and 13.5 GPa) of the MM composite, respectively. 相似文献
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以SiC 超细粉为原料、采用热等离子体物理气相沉积( TPPVD) 技术快速制备出了高质量SiC/ C 薄膜, 最大沉积速度达到225 nm/ s, 高于常规物理气相沉积( PVD) 和化学气相沉积(CVD) 法两个数量级。用扫描电子显微镜、高分辨透射电子显微镜和X 射线光电子谱对薄膜的形貌和微结构进行了观察和分析, 并用纳牛力学探针测定了薄膜的力学性能。研究结果表明, 向等离子体中导入CH4, SiC/ C 薄膜沉积速度增大, 薄膜中C 含量增加, 薄膜断面呈现柱状结构。薄膜硬度和弹性模量随薄膜中C 含量增加而降低, 在接触深度为40 nm 时由纳牛力学探针测得沉积薄膜的最大硬度达到38 GPa。 相似文献
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《Materials Science & Technology》2013,29(7):809-814
AbstractA336 Al matrix composites containing different volume fraction and mean mass particle size of SiC particles as the reinforcing phase were synthesised by evaporative pattern casting (EPC) route. The process consisted of fabricating of EPS/SiCp composite pattern followed by EPC of A336 Al alloy. The EPS/SiCp pattern was made by blending SiC particles with expandable polystyrene (EPS) beads and placing them in expanding mould heating with steam until EPS beads expand completely. Uniform distributed SiC particles around the EPS beads and locally movement of them during pouring and degradation leads to homogenous distribution of particles in final Al/SiCp composite. Higher modulus, strength and hardness were observed in the composites than the unreinforced Al alloy part. The fracture surfaces of the composite samples exhibited dimple surfaces and fracture in SiC particles. 相似文献
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In this work, the effect of SiC particle size and its amount on both physical and mechanical properties of Al matrix composite were investigated. SiC of particle size 70 nm, 10 μm and 40 μm, and Al powder of particle size 60 μm were used. Composites of Al with 5 and 10 wt.% SiC were fabricated by powder metallurgy technique followed by hot extrusion. Phase composition and microstructure were characterized. Relative density, thermal conductivity, hardness and compression strength were studied. The results showed that the X-ray diffraction (XRD) analysis indicated that the dominant components were Al and SiC. Densification and thermal conductivity of the composites decreased with increasing the amount of SiC and increased with increasing SiC particle size. Scanning electron microscope (SEM) studies showed that the distribution of the reinforced particle was uniform. Increasing the amount of SiC leads to higher hardness and consequently improves the compressive strength of Al–SiC composite. Moreover, as the SiC particle size decreases, hardness and compressive strength increase. The use of fine SiC particles has a similar effect on both hardness and compressive strength. 相似文献
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《Composites》1992,23(1):54-58
Fatigue crack propagation has been studied in two SiC particulate-reinforced aluminium-matrix composites with differing matrix alloys and composite heat treatments. Results indicate that the fatigue crack propagation rate (FCPR) of aged SiC/LY12 Al composites decreases with increasing volume fraction (Vf) of SiC particles; for composites containing 15 volume % SiC particles in an LY12 Al matrix the FCPR is independent of heat treatment (ageing or annealing). Annealed SiC/5083 Al composite has a higher FCPR than annealed SiC/LY12 AI. The influence of SiC particles on crack path is briefly discussed. 相似文献
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The effect of size of silicon carbide particles on the dry sliding wear properties of composites with three different sized
SiC particles (19, 93, and 146 μm) has been studied. Wear behavior of Al6061/10 vol% SiC and Al6061/10 vol% SiC/5 vol% graphite
composites processed by in situ powder metallurgy technique has been investigated using a pin-on-disk wear tester. The debris
and wear surfaces of samples were identified using SEM. It was found that the porosity content and hardness of Al/10SiC composites
decreased by 5 vol% graphite addition. The increased SiC particle size reduced the porosity, hardness, volume loss, and coefficient
of friction of both types of composites. Moreover, the hybrid composites exhibited lower coefficient of friction and wear
rates. The wear mechanism changed from mostly adhesive and micro-cutting in the Al/10SiC composite containing fine SiC particles
to the prominently abrasive and delamination wear by increasing of SiC particle size. While the main wear mechanism for the
unreinforced alloy was adhesive wear, all the hybrid composites were worn mainly by abrasion and delamination mechanisms. 相似文献
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Y. Yasutomi J. Sawada T. Kikuchi K. Nakamura Y. Manabe K. Nagano H. Kuroda T. Sumi H. Kubokawa M. Nagai H. Kogure Y. Sawai T. Kishi 《Journal of Materials Science》1999,34(7):1583-1593
Electrical power demands are increasing every year, meaning that lightweight electric cable is needed which has high transmission capacity, high thermal resistance and low sag. Tokyo Electric Power Co., Chubu Electric Power Co. and Hitachi Cable Ltd. have been breaking new ground in the field of electric cable through the development of a SiC fiber reinforced aluminum conductor. In this work, the SiC/Al interface reaction during the manufacturing process and the electricity transmission temperature were studied by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and field emission-Auger electron spectroscopy (FE-AES) for long-term reliability assessment. No reaction products were detected at the SiC/Al interface of elemental wire consisting of 7 SiC/Al preformed wires, indicating that the wire manufacturing process was reliable. An Al4C3 product was detected locally at the SiC/Al interface of the wire which had been thermally treated in molten Al under unfavorable conditions. The activation energy, Q, of Al4C3 growth at the SiC/Al interface was about 190 kJ/mol. In the temperature range of electricity transmission, Al atoms diffused into SiC fiber during heat treatment, and the amount of the diffused Al increased with increasing treatment temperature and holding time. The activation energy of Al diffusion through the SiC/Al interface to SiC fiber was about 78 kJ/mol. Strength deterioration was not induced by Al diffusion into SiC fiber, but strength strongly depended on the formation of Al2SiO5 compound at the SiC/Al interface above 400°C transmission temperatures. Kinetics calculations indicated that the rate of strength deterioration of the composite cable, held at 300°C for 36 years, was about 5%, so that practical use of SiC/Al composite cable should not be far in the future. 相似文献
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通过湿法混料和热压烧结工艺成功地制备了20vo1%SiCP/MoSi2复合材料,并测定了其显微组织和力学性能。结果表明:SiCP/MoSi2复合材料主要由MoSi2和SiC颗粒组成,还有少量的Mo5Si3,致密度为92.3% 。与MoSi2相比,其室温抗弯强度提高了30.6%,断裂韧性提高了53%,1200℃的抗压强度提高了44%,1400℃的抗压强度提高了53%;其硬度、弹性模量等性能有较大提高。在Al2O3和SiC对磨盘上表现出极其优异的耐磨性能。SiC颗粒对MoSi2的室温增韧、高温增强效果显著。 相似文献