烧结温度对SPS制备ZrW2O8/Al复合材料组织与性能的影响

Effect of Sintering Temperature on Microstructure and Properties of ZrW2O8/Al Composite Prepared by SPS

摘要:

采用放电等离子烧结法，分别在不同烧结温度下制备50%ZrW₂O₈/Al复合材料，并研究了复合材料的微观组织、物相组成、致密度、热膨胀系数及热导率。结果表明：不同温度制备的复合材料均含有γ-ZrW₂O₈。随着烧结温度从475 ℃逐渐提高到575 ℃，复合材料的密度和γ-ZrW₂O₈含量均逐渐升高。经25~300 ℃第1次热膨胀实验去应力后，复合材料中γ相含量显著减少。第2次热膨胀实验测得，随烧结温度升高，热膨胀系数先增大后减小，525 ℃样品最高（4.6×10^-6 K^-1）。ZrW₂O₈/Al复合材料的烧结致密度显著影响其性能，525 ℃烧结复合材料的致密度高（92.9%）、热导率最大（31.9 W/m·K）。525 ℃是兼顾复合材料的成分稳定和烧结致密度的最优烧结温度。

Abstract:

50%ZrW₂O₈/Al composites were prepared by spark plasma sintering. The effect of sintering temperatures on the microstructure, phase composition, density, thermal expansion coefficient and thermal conductivity of the composites was studied. The results show that the composites sintered at different temperatures contain γ-ZrW₂O₈. As the sintering temperature gradually increases from 475 ℃ to 575 ℃, the density and content of γ-ZrW₂O₈ in the composites gradually increase. After a process of stress relief by the first thermal expansion test from room temperature to 300 °C, the content of γ-ZrW₂O₈ in the composite material is significantly reduced. The second thermal expansion test reveals that as the sintering temperature increases, the thermal expansion coefficient first increases and then decreases, with the sample sintered at 525 °C being the highest (4.6×10^–6 K^–1). The sintering density of the composite significantly affects its performance. The ZrW₂O₈/Al composite sintered at 525 °C presents both the highest density (92.9%) and thermal conductivity (31.9 W/m·K). 525 ℃ is the optimal sintering temperature that takes into account the composition stability and sintering density of the composites.