陶瓷材料超塑性研究进展

Superplasticity in Ceramics

超塑性是细晶陶瓷在高温下的固有属性。本文综述了陶瓷材料超塑性的一般特征和氧化钇稳定四方相氧化锆多晶陶瓷(Y-TZP)的形变机理及最新研究进展。解释了不同纯度Y-TZP陶瓷在Ⅰ区存在巨大差异的原因以及杂质特征对应力指数的影响。从能量的观点进一步分析了陶瓷材料超塑变形过程中的控速机制。对共价键陶瓷Si3N_4、SiC的超塑性特征以及晶间玻璃相在超塑变形中的作用进行了概括。此外,还总结了其它陶瓷材料,包括Al_2O_3及其复合陶瓷、纳米陶瓷的研究进展及发展方向。

It is clearly demonstrated that the superplasticity is one of the common properties of fine-grained ceramics at elevated temperatures. The paper reviewed the major features of superplasticity in ceramics, the deformation characteristics and mechanism of yttria-stabilized tetragonal zirconia polycrystals(Y-TZP), a typical superplastic ceramic. The reason for the difference in region 1 between high-purity and low-purity Y-TZP was explained, then the effects of impurities on the apparent stress exponent were found out. The rate controlling mechanism in superplasticity was also analyzed from the point of activation energy. The superplastic characteristics Of Si3N4 covalent ceramics enhanced by intergranular glass phase was studied, hence the role of the intergranular glass phase in superplasticity was defined. The superplastic behavior of other ceramic materials, including Al2O3, aluminium based composites, covalent ceramic materials and nano-structured ceramics were also summarized.