【作者】 薛宗伟；

【导师】 费维栋；

【作者基本信息】 哈尔滨工业大学 ， 材料科学与工程， 2007， 硕士

【摘要】 本文利用真空热压烧结工艺成功制备了不同体积分数β-锂霞石为增强体的铜基复合材料,并对烧结态的复合材料我们进行了退火处理和热挤压处理。利用X射线衍射(XRD)、金相显微镜(OM)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等方法对β-锂霞石/铜复合材料进行了物相、表面形貌、断口形貌和界面特征分析;利用热膨胀分析和热传导测量设备对β-锂霞石/铜复合材料的烧结态、退火态和热挤压态分别进行了热物理性能测试和分析。采用真空热压烧结法成功制备了β-锂霞石分布均匀的铜基复合材料。新发现在真空退火的过程中β-锂霞石发生了分解消失。β-锂霞石颗粒在复合材料中在大范围内分布均匀,但是微观分布有团聚现象。随着β-锂霞石体积分数的增加,团聚现象更加明显。复合材料中β-锂霞石与铜的界面结合能力很差;β-锂霞石与铜的界面清晰,没有发生界面反应。复合材料的致密性随着β-锂霞石体积分数的增加而降低,当体积分数达到50%时,复合材料的致密性只有89%。随着β-锂霞石体积分数的增加,复合材料的线平均热膨胀系数降低。复合材料的热错配应力对热膨胀系数有很大的关系。在升温过程中,当增强体压应力松弛和拉应力产生时,复合材料的热膨胀系数小于按混合法则计算的结果,当增强体中拉应力松弛时,复合材料的热膨胀系数大于按混合法则计算的结果。退火处理和热挤压可以降低β-锂霞石/铜复合材料的热膨胀系数。这主要是因为退火处理改善了复合材料中热残余应力分布状态和使复合材料的界面结合更加良好。热导率随着β-锂霞石颗粒体积分数的增加而减小;热挤压可以提高复合材料的热导率。更多还原

【Abstract】 β-Eucryptite（Euc） particles reinforced copper matrix composites, with the different volume fraction , were fabricated by vacuum heating-press sintering. The micro-structure of Euc/Cu composites was studied by optical microscope, scanning electron microscope and transmission electron microscope. The compactness of Euc/Cu composites was analyzed by means of analytical balance. The thermal physical properties of Euc/Cu composites were analyzed by means of thermal dilatometer, thermal conductivity tester, also with their influencing factors discussed.Analyses indicate that there is not interfacial reaction at Euc/copper interface. After the composites were annealed 4 hour at 1000℃, the surfaced Euc of the composites was disappear.In the macroscopic state, the dispersed Euc in the copper matrix is uniformity. In the microscopic state, there was the aggregation phenomenon of Euc particles in the composites. With the volume of Euc increasing, the aggregation phenomenon of Euc particles in the composites was more evidently. There are obverse holes around the Euc particles.With the Euc volume increasing, the densification of the composites is decreasing. When the volume fraction increased to 50%, the densification of the composites decreased to 89%.With the Euc volume increasing, the average coefficient of thermal expansion of the composites is decreasing. When the volume fraction increased to 50%, the CTE of the composites decreased to 10.5×10^-6℃^-1.The studies of thermal expansion behaviors of the composites show that the residual stress relaxation affects greatly the coefficient of thermal expansion of the composite.The annealing process can decrease the coefficient of thermal expansion of composite, the main reason is that the vacuum anneal can change the stress state and improve the interface binding strength.The thermal conductivity of the composite decreased with the volume of the Euc increasing .The thermal extrusion can make the composites so dense that the thermal conductivity of composites decreased.更多还原