超临界相变陶瓷的韧性增值

Toughness Enhancement in Supercritical Transformation Ceramics

采用近似方法研究应力非奇异项对小范围相变条件下超临界相变陶瓷韧性增值的影响。材料相变屈服准则包含了体膨胀和剪切应变的作用。文中给出了韧性增值的估算公式。结果表明：非奇异项的影响是显著的，相变增韧值存在尺寸效应，并且相变剪切效应增强会使韧性增值有所提高。

In this paper, we examine the influence of the nonsingular stress terms on the toughness enhancement of smallscale supercritical transformation ceramics. The transformation yield condition includes the dilatantional and shear effect. The formula for estimating the toughness enhancement is presented. It is found that the nonsingular terms can affect the toughness considerably, and the toughness curves are geometry dependent and their values increase with the shear effect increasing. The results may be very useful in the fracture toughness testing of transformation ceramics.