WC_p/2024Al复合材料热学性能研究

Study on Thermal Properties of WC_p/2024Al Composite Materials

利用粉末冶金法制备了WC颗粒体积分数分别为8%、11.8%、16.7%的WCp/2024Al复合材料,采用扫描电子显微镜、热膨胀分析仪、热导率测试仪等多种手段研究不同WC体积分数、挤压比和热处理对复合材料热膨胀系数(CTE)、热导率和微观结构的影响。结果表明:复合材料的热膨胀系数随WC体积分数的增大而明显降低,随挤压比的增大而提高,经过T4态热处理后,复合材料内应力的降低和第三相的析出导致其热膨胀系数降低,热膨胀系数的实测值与kermer模型的计算值相近。复合材料的热导率随WC体积分数的增大而降低。

WCp/2024Al composites with WCp volume fractions of 8%,11.8% and 16.7% were fabricated by powder metallurgy method.The effect of WCp volume fraction,extrusion ratio and thermal conductivity are tested.The results show that the CTE of WCp/2024Al composites decline with the increase of WCp content and the reduced extrusion ratio,respectively.The decrease in CTE of WCp/2024Al composites are attributed to the reduced internal stress and the T4 heat treatment.The thermal conductivity and microstructure of WCp/2024Al composites is investigated by scanning electron microscope,dilatometer.The measured coefficients of thermal expansion agree well with Kerner＇s model.The thermal conductivity of the composites declines with the increase of WC volume fraction.