PZT薄膜界面分层破坏的内聚力模拟  

Cohesive zone modelling of interfacial delamination in PZT thin films

作　　者：闫亚宾[1] 尚福林[1] 

机构地区：[1]西安交通大学航天航空学院工程力学系,西安710049

出　　处：《中国科学（G辑）》2009年第7期1007-1017,共11页

基　　金：国家自然科学基金(批准号:90607013);国家重点基础研究发展计划(编号:2007CB707702)资助项目

摘　　要：实验测试表明,单晶硅基板上磁控溅射沉积的多层薄膜材料Cr/PZT/PLT/Pt/Ti容易沿着Cr/PZT界面端开裂并发生分层破坏.我们在实验测试基础上,通过数值模拟计算与分析研究,确定了该薄膜界面的结合强度参数.模拟计算基于连续介质力学的内聚力模型,采用有限元方法来分析沿Cr/PZT界面的裂纹萌生和扩展过程.首先,将该界面表征为一个遵从指数或双线性内聚力模型本构关系的薄层.然后,通过与实测的断裂载荷、加载点的载荷-位移曲线校准的办法,确定出界面内聚法则参数.研究发现,内聚强度和内聚能是最为关键的内聚参数;双线性内聚力模型更适合于描述Cr/PZT界面破坏;与毫米量级厚度的薄膜材料相比,该多层薄膜材料中的Cr/PZT界面的内聚能较低,属于弱结合界面,沿着该界面的分层破坏为脆性断裂过程.本研究表明,宏观力学的内聚力模型同样适用于分析微米厚度薄膜的界面破坏问题.Previous experimental tests have demonstrated that the multilayered Cr/PZT/PLT/Pt/Ti thin films deposited on single crystal Si substrate tend to delaminate along the interface between PZT and Cr layers in a brittle manner. This study starts from modeling based on cohesive zone concept and carries out finite element simulations to check the delamination behavior along the Cr/PZT interface. Two cohesive zone models （CZMs） of exponential type and bilinear type are adopted, and the characteristic CZM parameters are extracted through calibration via the experimental results. The simulation results show that cohesive strength and cohesive energy are the domi- nating CZM parameters; the bilinear CZM more suitably describes this brittle interfacial delami- nation; in comparison with typical several mm-thick film/coating materials, the fracture energy of this weak Cr/PZT interface is quite low. Our study demonstrates the applicability of CZM for characterizing the interface fracture behavior of film materials of micrometer thicknesses.

关 键 词：界面 分层 内聚力模型 薄膜材料 

分 类 号：O346.1[理学—固体力学]