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(MoNbTiVZrW)C高熵陶瓷制备温度,力学性能及氧化行为研究

Preparation temperature, mechanical properties and oxidation behaviour of (MoNbTiVZrW)C high entropy ceramics

  • 摘要: 本文以碳化物粉末为原料,采用高能球磨(HEBM)及放电等离子烧结(SPS)的方法制备了(MoNbTiVZrW)C高熵陶瓷,并研究了烧结温度(1600~2000℃,间隔100℃)对高熵陶瓷组织及力学性能的影响。结果表明,烧结过程中,除少量ZrC被氧化外,各碳化物充分固溶的最低温度为1800℃,烧结试样以FCC结构的(MoNbTiVZr)C高熵陶瓷相为主。1600~2000℃温度下烧结的(MoNbTiVZr)C高熵陶瓷的致密度均达97%以上,平均晶粒尺寸随烧结温度升高而增大,硬度及断裂韧性随烧结温度升高呈下降趋势。当烧结温度为1800℃时,制备的陶瓷综合力学性能较佳,硬度和断裂韧性分别可达20.86±0.74 GPa和4.90±0.21 MPa·m1/2。1800℃温度下制备的(MoNbTiVZrW)C高熵陶瓷开始氧化温度大致为480℃,在830℃时氧化增重达到最大。

     

    Abstract: (MoNbTiVZrW)C high-entropy ceramics were prepared by high-energy ball milling (HEBM) and discharge plasma sintering (SPS) using carbide powders as raw materials, and the effects of sintering temperature (1600~2000°C with 100°C interval) on the organisation and mechanical properties of high-entropy ceramics were investigated. The results show that during the sintering process, except for a small amount of ZrC being oxidized, the lowest temperature at which the carbides are fully solidified is 1800°C, and the sintered samples are dominated by (MoNbTiVZr)C high-entropy ceramic phases of FCC structure.The densities of (MoNbTiVZr)C high-entropy ceramics sintered at 1600~2000°C are all more than 97%, and the average grain sizes are increased with the increase of sintering temperature. The average grain size increases with the increase of sintering temperature, and the hardness and fracture toughness show a decreasing trend with the increase of sintering temperature. When the sintering temperature is 1800 ℃, the comprehensive mechanical properties of the prepared ceramics are better, and the hardness and fracture toughness can be up to 20.86 ± 0.74 GPa and 4.90 ± 0.21 MPa-m1/2, respectively.The oxidation temperature of (MoNbTiVZrW)C high-entropy ceramics prepared at 1800 ℃ is about 480 ℃, and the oxidation weight gain reaches the maximum at 830 ℃.

     

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