钛酸铅颗粒增强铜基复合材料的性能研究

发布时间：2018-04-18 08:12

本文选题：钛酸铅 + 铜基复合材料　；参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：本文选择具有负膨胀性能的钛酸铅(Pb Ti O3,简写PT)陶瓷颗粒作为复合材料的增强体,选择具有高热导率的铜作为复合材料的基体,采用放电等离子烧结工艺制备了体积分数不同的钛酸铅颗粒增强铜基复合材料。利用物相及微观组织结构分析方法(XRD、SEM、TEM等)观察了复合材料中增强体与基体的形貌、界面特征、增强体与基体中位错孪晶情况。采用热膨胀仪和热导率测试设备测试并分析了复合材料的热膨胀性能和导热能力。利用电子万能试验机测试了复合材料的压缩屈服强度;利用智能电阻测试仪测试了复合材料的电导率。物相和微观结构分析表明,放电等离子烧结制备的Pb Ti O3/Cu复合材料具有清晰光滑的界面形貌,而且看不到明显的界面反应,增强体与基体界面结合较弱。TEM观察结果证实烧结态的复合材料中有大量的位错、孪晶产生,表明复合材料中存在大量的热错配应力。复合材料的热膨胀系数与PT颗粒的体积分数成负相关性,即PT颗粒的体积分数越大,复合材料的热膨胀系数越低。复合材料界面结合较弱且内部残余应力复杂,导致复合材料热膨胀系数不稳定,但是可以通过适当的热处理来提高热膨胀系数的稳定性。通过Zr掺杂可以降低钛酸铅的居里温度,PZT/Cu复合材料在较低温度就能产生窄而强烈的负膨胀行。增强体体积分数和分布情况明显影响复合材料的热导率。当增强体体积分数较高时,一方面增强体的低热导率导致整个复合材料的热导率降低,另一方面增强体体积分数较高时,复合材料中产生了更多的界面,界面阻碍热传导,从而进一步降低复合材料的热导率。复合材料的压缩屈服强度对增强体与基体界面状态和增强体分布均匀性较敏感。复合材料的电导率与增强体体积分数成负相关,且热循环会改善复合材料的电导率。
[Abstract]:In this paper, lead titanate (PbTiO _ 3) ceramic particles with negative dilatability are selected as reinforcements of composites, and copper with high thermal conductivity is chosen as matrix of composites.Copper matrix composites reinforced by lead titanate particles with different volume fraction were prepared by spark plasma sintering (SPS).The morphology, interfacial characteristics and dislocation twins of the reinforcements and the matrix in the composites were observed by means of phase and microstructure analysis.The thermal expansion properties and thermal conductivity of the composites were tested and analyzed by means of thermal expansion instrument and thermal conductivity test equipment.The compressive yield strength of the composite was measured by the electronic universal tester and the conductivity of the composite was measured by the intelligent resistance tester.The results of phase and microstructure analysis show that the PbTi O3/Cu composites prepared by SPS have clear and smooth interface morphology, and there is no obvious interface reaction.The observed results of weak interface between reinforcements and matrix show that there are a large number of dislocations and twinning in the sintered composites, which indicates that there are a lot of thermal mismatch stresses in the composites.The thermal expansion coefficient of the composites is negatively correlated with the volume fraction of PT particles, that is, the larger the volume fraction of PT particles, the lower the thermal expansion coefficient of the composites.The interfacial bonding of the composites is weak and the internal residual stress is complex, which leads to the instability of the thermal expansion coefficient of the composites, but the stability of the thermal expansion coefficient can be improved by proper heat treatment.Zr doping can reduce the Curie temperature of PZT / Cu composites and produce narrow and strong negative expansion lines at lower temperatures.The volume fraction and distribution of the reinforcements have a significant effect on the thermal conductivity of the composites.When the volume fraction of reinforcements is high, on the one hand, the low thermal conductivity of the reinforcements leads to the decrease of the thermal conductivity of the composites; on the other hand, when the volume fraction of the reinforcements is high, more interfaces are produced in the composites, which hinder the thermal conduction.Thus, the thermal conductivity of the composites is further reduced.The compressive yield strength of the composites is sensitive to the interface state between the reinforcements and the matrix and the distribution uniformity of the reinforcements.The conductivity of the composites is negatively correlated with the volume fraction of the reinforcements, and thermal cycling can improve the conductivity of the composites.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB333

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