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应用科学学报 ›› 1996, Vol. 14 ›› Issue (4): 385-390.

• 论文 • 上一篇    下一篇

热历史对Sialon/SiC(p)复合陶瓷的相稳定性及力学性能的影响

刘茜1, 高濂1, 严东生1, H MANDAL2, D P THOMPSON2   

  1. 1. 中国科学院上海硅酸盐研究所;
    2. 英国纽卡斯尔大学
  • 收稿日期:1995-07-29 修回日期:1996-01-19 出版日期:1996-12-31 发布日期:1996-12-31
  • 作者简介:刘茜:副研究员,中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室,上海 200050
  • 基金资助:
    英国皇家学会资助研究项目

EFFECTS OF THERMAL HISTORY ON MECHANICAL PROPERTICS OF AGGLOMERATE-FREE SiC(p) REINFORCED SIALON COMPOSITES

LIU QIAN1, GAO LIAN1, YAN DONGSHENG1, H MANDAL2, D P THOMPSON2   

  1. 1. Shanghai Institute of Ceramics, Chinese Academy of Sciences;
    2. University of Newcastle upon Tyne
  • Received:1995-07-29 Revised:1996-01-19 Online:1996-12-31 Published:1996-12-31

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摘要： 研究热处理对致密Ln-Sialon/SiC(p)复合陶瓷中α相稳定性的影响及由此引起的显微结构调控和力学性能变化,其中Ln=Nd和Yb.Nd-Sialon/SiC(p)中,α相热稳定性差,几乎全部相变为β相,而大量长柱状β晶粒的存在并未明显改善材料的断裂韧性(KIC),原因在于长时间热处理导致晶粒相互聚集粗化.相对而言,Yb2O3可有效稳定α相,因此Yb-Sialon/SiC(p)中含有许多等轴状α晶粒,高硬度是此种材料力学性能的显著特征.

关键词: SiC, 热处理, 力学性能, 复合材料, Sialon

Abstract: Densified SiC(p) reinforced Ln-Sialon(Ln-Nd and Yb) composites were fabricated to evaluate the improvement in microstructure and mechanical properties that can be achieved by α→β transformation induced by heat treatment.Nd-and Yb-Sialon/SiC(p) composites possess quite different reactions to thermal history. Under the same conditions for heat treatment, α phaso is quitg unstablein the Nd-Sialon/SiC(p) system and almost thoroughly transforms to β phase, with aluminum-containing melilite(M') left at pockets of grain junctions as a dominant grain boundary phase. Despite a great many elongated β grains,existing in the Nd-system, fracture toughness (KIC) was not improved because the decrease of aspect ratio and occurrence of coalescence of grains caused by a longer heat treatment might degrade mechanical properties, especially KIC values. Comparatively speaking, Yb2O3 is a kind of better densifying additive for the composites and more efficient to stabilize α structure than Nd2O3. As a result, Yb-Sialon/SiC(p) composited possess higher hardness (Hv) owing to a lot of equiaxed α grins developing in the materials.

Key words: SiC, heat-treatment, Sialon, composite, mechanical properties