孔隙分布不均匀性对陶瓷材料强度的影响

Influence of pore distribution nonuniformity on strength of ceramic

由于工艺特殊性,一些陶瓷材料中不可避免地存在孔隙、夹杂等缺陷,且孔隙、夹杂大多分布不均匀,而这种不均匀性对陶瓷材料力学性能有较大影响。根据分布不均匀性特点,以陶瓷材料中孔隙分布为例,定义了均匀度对孔隙分布的不均匀性进行量化,提出了利用图像处理确定均匀度的方法。根据图像处理结果,将材料分为富含孔隙的等效基体相和不含孔隙的等效颗粒相,利用相互作用直推估计(IDD)法研究了材料强度随均匀度的变化关系。结果表明:孔隙分布均匀度对材料强度有较大影响,孔隙分布的均匀度越小,材料强度越低,并且在均匀度低于0.2时造成强度的剧烈降低,当均匀度大于0.5时,对材料强度的影响很小。

Pores,inclusions and other defects in ceramics are inevitable due to the special process,and they generally ununiformly distribute,this nonuniformity has big impact on ceramic properties.Base on the pore distribution characteristic in ceramics,the parameter uniformity was defined to quantize the uniformity of pore and inclusions distribution,and an image processing method was introduced to confirm the uniformity.According to the image processing results,ceramic was divided to two parts,the effective matrix phase enriched pores and the effective grain phase without pores.Based on interact direct derivative(IDD)estimate,the relationship between strength and uniformity was analyzed.The results indicate that uniformity has significant influence on the strength of ceramic,the strength reduces with uniformity decreasing,especially when the uniformity is lower than 0.2,and influence of uniformity is limited when it is higher than 0.5.