摘要
机械损伤是否产生取决于损伤驱动力及损伤抗力 ,对于陶瓷涂层而言 ,区别于单质固体的是 ,其损伤驱动力及损伤抗力二者都与材料本身相关 ,二者都受涂层与基体材料间的热学及力学匹配、涂层与基体材料的弹塑性性能、涂层的厚度及显微组织、以及涂层与基体界面的粗糙度等因素的影响。因此 ,涂层的热—机械行为的完整表征必须借助于基于破坏机制的损伤图才能完成。这种损伤图将相关参数有机地结合在一起 ,从而定出损伤安全区。而建立这种损伤图 ,必须有可靠的实验技术以测定涂层及界面的断裂韧性。而这种测试技术仍处于发展阶段 ,迄今并无完善的方法。作者正在研究及发展的多应变开裂及失稳试验 ,可能是目前最为简便易行而可靠的方法。本文略述测试与损伤图相关的参数的试验方法。
From the perspective of coating design and life prediction, a fundamental understanding of the mechanical failure, as well as a mechanism-based thermomechanical characterization of the coating are needed. To illustrate the recent advances in this area, the basic mechanics of channel cracking and debonding or delamination of hard coatings are briefly described. The tactics for the measurements of the toughness and adhesion of ceramic coatings is introduced. To demonstrate the effectiveness of the suggested experimental techniques, some results are presented. It is emphasized that a complete thermomechanical characterization of the coating/substrate system requires evaluation of both the driving force for the failure and the resistance to the failure. Since none of them can be characterized by a single parameter, failure maps for various failure modes are necessary.
关键词
机械损伤
陶瓷涂层
损伤图
力学性能测试
ceramic coatings
mechanical failure
cracking, adhesion
failure maps
