微弧氧化陶瓷层的断裂行为研究

Micro-Arc Oxidation technology is widely applied to improve the surface performance of light metal mechanical components. The binding strength between the ceramic layer and the substrate becomes an important index to evaluate the applicability of ceramic layer. Under friction and thermal shock environment, part of ceramic layer come to break and peel, the fundamental reason is that the material property of ceramic layer is very different from substrate. Then, the stress at the interface too concentrated to become crack propagation. Based on previous studies, the applicant propose to improve the bonding strength between ceramic layer and substrate by designing crystalline phase and structure of interface between ceramic layer and substrate, and to provide theoretical basis for optimization ceramic layer preparation process by researching fracture behavior of ceramic layer. The subject research is going to carry out include: research of multistage micro-arc oxidation preparation process, which ceramic layer/ substrate interface material must be controllable; research of accurate measured method about elastic modulus of ceramic layer; research of stress and strain distribution around layer/ substrate interface, and the applicability of fracture parameter on micro-arc oxidation ceramic layer fracture calculation, and the bonding and fracture toughness properties of ceramic layer/ substrate interface.

微弧氧化陶瓷化技术广泛应用于提高轻金属机械构件的表面性能领域，陶瓷层与基体的结合强度成为评价陶瓷层适用性的重要指标。在摩擦和热震环境下，陶瓷层局部会发生断裂和剥离，其根本原因是陶瓷层与基体的材料属性差异大和界面处应力集中导致的裂纹扩展。申请人在前期研究的基础上，提出通过设计陶瓷层/基体界面的晶相和结构，提高陶瓷层与基体的结合强度，并通过有限元方法模拟研究微弧氧化陶瓷层的断裂行为，为优化陶瓷层制备工艺提供理论依据。课题拟进行的研究主要为：陶瓷层/基体界面材料可控的多级微弧氧化制备工艺研究；陶瓷层弹性模量准确测量的方法研究；陶瓷层/基体界面附近应力应变分布特征分析，断裂参量在微弧氧化陶瓷层断裂计算方面的适用性研究，陶瓷层/基体界面结合性能和断裂韧性研究。

微弧氧化陶瓷化技术广泛应用于提高轻金属机械构件的表面性能领域，陶瓷层与基体的结合强度成为评价陶瓷层适用性的重要指标。本项目首次综合研究了微弧氧化陶瓷层的断裂力学特性，采用多种实验手段测量了陶瓷层的弹性模量，建立了陶瓷层/基体的本构模型；探究了不同厚度陶瓷层对试样表面及界面应力的影响，不同法向载荷对模型位移及应力场分布变化的影响，并进行了陶瓷层/基体界面附近应力应变分布特征分析；采用M、J守恒积分针对陶瓷层复合材料进行了断裂特性适用性研究，利用扩展有限元计算模型对应的积分值，分析了材料行为、外部条件、缺陷构型与守恒积分的关联性和规律性。通过断裂力学研究，返回指导微弧氧化制备工艺，创建了两阶段式微弧氧化工艺。