外场作用下BaTiO₃单晶裂纹扩展和畴变

来源期刊：金属学报2011年第5期

论文作者：姜冰 邢献然 郭志猛

文章页码：605 - 610

关键词：铁电畴变； 裂纹扩展； 原位观察； BaTiO₃单晶

Key words：domain switching； crack propagation； in-situ observation； BaTiO₃ single crystal

摘    要：通过偏振光显微镜对连续应力和恒电场作用下的BaTiO₃单晶中的裂纹扩展和畴变过程进行原位观察.结果表明.在连续应力的作用下,裂尖处应力集中导致出现畴变带,裂纹与畴变带垂直相交,畴带和裂纹一起向前移动,畴变在先,裂纹扩展在后;在恒电场作用下,畴变引起的不协调应变导致电致裂纹扩展,畴变始终发生在裂纹扩展之前.裂纹向前扩展时不断的切过前方的畴带,直到不再有畴变发生时裂纹停止扩展.

Abstract: Domain switching and crack propagation in BaTiO₃ single crystal under external field were in-situ observed by polarized light microscopy (PLM).It was found that under mechanical field, domain-switching bands appear around the crack tip to relax stress and domain switching occurred before crack propagation.Under electric field,the internal stress induced by domain switching results in crack propagation.