钛酸钡铁电单晶压痕诱发微裂纹形成与90°铁电畴变  

INDENTATION-INDUCED CRACKING AND 90° DOMAIN SWITCHING IN BARIUM TITANATE FERROELECTRIC SINGLE CRYSTALS

作　　者：方菲[1] 杨卫[1] 

机构地区：[1]清华大学工程力学系国家教育部破坏力学开放实验室,北京100084

出　　处：《硅酸盐学报》2003年第12期1140-1144,共5页Journal of The Chinese Ceramic Society

摘　　要：用偏光显微镜和扫描电子显微镜观察研究了不同取向BaTiO3铁电单晶在Vickers压痕作用下微裂纹与90。铁电畴变的形态。发现对于[001]取向极化的BaTiO3铁电单晶,压痕诱发短裂纹不仅发生在沿着压痕对角线方向,而且由于相邻等价畴变区界面的结构错配,还发生在与压痕对角线成45°的方向。对于[100]取向的BaTiO3铁电单晶,在偏离水平方向(垂直于极化方向)约15°～20°角出现了对偶长裂纹。如果将压痕的对角线从极化方向旋转45°,则压痕诱发的裂纹长度大大缩短。认为由于结构错配的影响,裂纹倾向于沿着两畴变区的界面或沿着已畴变区和未畴变区的界面形成。Different ferroelectric domain switching and indenting crack patterns under Vickers indentation for BaTiO3 single crystals poled in different directions were studied by means of polarizing microscope and SEM. It is found that for [001]-oriented BaTiO3 single crystal, the short indenting cracks occur not only at the diagonals of the indentation, but also at 45?away from the diagonals of the indentation due to the structure mismatch along the boundaries between two adjacent domain-switching zones of equivalent spreading. For [100]-oriented BaTiO3 single crystal, two pairs of long cracks occur at approximately 15°-20° away from the horizontal direction that is normal to the poling direction. Much shorter cracks will occur if one diagonal of the indentation is put 45° away from the poling direction. Driven by the structure mismatch, cracks prefer to form along the boundary of two adjacent domain-switching zones, or from the boundary dividing the domain switch zone and non-switching zone due to the effect of structure mismatch.

关 键 词：钛酸钡 铁电单晶 极化 铁电畴变 

分 类 号：O731[理学—晶体学]