陶瓷基复合材料界面微区力学行为的研究进展

Research progress in micro-mechanical behavior of ceramic matrix composites interfacial zone

作为热结构材料,陶瓷基复合材料(ceramic matrix composites,CMC)在航空航天领域应用潜力巨大。连续纤维的引入解决了陶瓷脆性大的问题,而纤维与基体间微小区域——界面层的设计是保证CMC具有高韧性的关键。一直以来相关研究主要集中于界面层与CMC宏观力学性能之间的关系,受限于表征难以深入研究界面层微区力学行为的困难。随着微纳力学测试与聚焦离子束(focused ion beam,FIB)技术的发展,近些年来对于CMC界面层结合强度以及其失效行为的表征逐渐增多。在此基础上,本文综述CMC中界面层的作用以及界面剪切强度的影响因素与调控机制,同时汇总当下通过直接或间接手段测试界面剪切强度的方法,重点总结微纳力学手段下纤维push-out/push-in以及微柱压缩等方法的适用条件以及差异,报道这些方法在界面区失效机制研究方面的进展,并指明尚存在的一些问题。其中,纤维pushout/push-in可以反映基体应力作用对界面剪切强度的影响,但测试结果可能受到外部因素的影响;而微柱压缩测试则更多地反映界面层本征特性,无法反映基体应力对界面剪切强度的影响,也无法反映纤维拔出过程。最后展望未来的研究方向:进一步拓展界面微区力学行为的表征方法,同时确定微区力学与宏观力学性能间的影响机制并建立模型,最终实现CMC的界面层优化。

Ceramic matrix composites(CMC)have excellent application potential in the aerospace field as thermal structure material.The introduction of continuous fibers solves the problem of high brittleness of ceramics,and the interphase.A micro area between fiber and matrix,plays an important role in guaranteeing the high toughness of CMC.In the last decades,relevant research mainly has focused on the relationships between the interphase and the macroscopic mechanical properties of CMC.Due to the limitation of characterization technology,it is difficult to study deeply the micro-mechanical behavior in the interface region.With the development of micro-nano mechanical testing and focused ion beam(FIB)technology,the characterization of CMC interfacial layer bonding strength and its failure behavior have gradually increased in recent years.On this basis,the interphase roles,the influencing factors of interfacial shear strength and the regulation mechanism of interphase were reviewed.The current methods of testing interface shear strength by direct or indirect means were summarized.The applicable conditions and differences of fiber push-out/push-in and micro pillar compression methods were summarized empathetically.The progress in failure mechanism of the interfacial zone was revealed,and some remaining problems were pointed out.The fiber push-out/push-in test can reflect the influence of matrix stress on the interfacial shear strength,but the test results might be influenced by external factors.And the micro pillar compression test primarily reflects the intrinsic properties of the interphase,and can’t reflect the influence of the matrix stress on the interfacial shear strength,nor can it reflect the fiber pull-out process.Finally,the future research directions are prospected:further expanding the characterization methods of the mechanical behavior of the interface micro-zone,while clarifying the influence mechanism between the micro-mechanical behavior and the macroscopic mechanical properties,and establishing relevant models,ultimately achieving the optimization of the interfacial zone of CMC.