在Dy-Si-Al-O-N系统相关系的研究基础上,设计了以DyAG和M’相作为晶界相的单相α-Sialon和β-Sialon以及复相α-β-Sialon材料.研究了它们的致密化行为,热处理过程中的α’→β’相变机制以及力学性能.结果表明:可以制备出以DyAG和M’相作为晶界相的单相α-Sialon和β-Sialon以及复相α-β-Sialon材料.作为烧结助剂,DyAG比M’更能有效地促进致密化.Dy-α’较之其他的含Dy的物相更易于形成,因此烧结样品的α’相含量比设计值高.通过热处理,使α’→β’转变发生,可以达到设计的α’/α’+β’值.
Based on the phase relationships in the Dy-Si-Al-O-N system, α-Sialon ceramics and α-β-Sialon composite ceramics with garnet and/or melilite as grain boundary phases were designed. The densification behavior, α’→β’ phase transformation in heat-treatment, mechanical properties and microstructure characteristic were studied. The results show that Dy-α’ and Dy-α’-β’ ceramics with garnet and/or M’ as grain boundary phases can be fabricated by HP. DyAG as an additive is more effective than M’ in promoting densification. Dy-α’ is kinetically more favourable to be formed over the other Dy-containing phases unlike the other Ln-α-Sialons, thereby the fractions of the α’ phase in the as sintered specimens is higher than the designed ones. By post sintering heat-treatment, the α’→β’ phase transformation occurs and the designed
α’/α’+β’ ratios can then be achieved.
参考文献
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