Mechanism-based characterization of the fatigue and corrosion fatigue properties of addtively manufactured TPMS lattice structures under physiological conditions

该分项目的总体目标是对用PBF-LB/M方法制造的涂层Ti-6Al-4V晶格结构在循环加载和腐蚀暴露下的微观和机械变形和损伤行为的整体表征。由于情况复杂，加载条件将首先单独考虑，然后集中考虑，以便分别检测主要机制。在通过时间效率腐蚀和准静态试验确定了PBF-LB/M工艺参数的影响后，定义了用于基于三周期极小曲面(TPMS)的简化2D几何制造的最佳参数集。由于在空气中的疲劳强度和循环损伤机制，将选择一种受欢迎的2D晶格类型来进一步表征涂层的承载能力和腐蚀性能。其目的是建立对简化的2D几何图形的机械和腐蚀特性的广泛理解，然后将其转移到3D晶格结构。为了表征面向应用的损伤行为，将进行三维网格结构的体外腐蚀疲劳试验。进一步，对骨/种植体界面的力学行为(体外)进行了表征，并量化了刚度失配(应力屏蔽)。

The overall objective of the subproject is the holistic characterization of the microscopic and mechanical deformation and damage behavior under cyclic loading as well as corrosive exposure of coated Ti-6Al-4V lattice structures manufactured by means of PBF-LB/M. Due to the complex scenario, the loading conditions will be first regarded separately and later on collectively in order to detect the dominant mechanisms, respectively. After determining the influence of the PBF-LB/M process parameters through performing time-efficient corrosion and quasi-static tests, an optimal parameter set is defined which is used for manufacturing of simplified 2D geometries based on triply periodic minimal surfaces (TPMS). Resulting from the fatigue strength and the cyclic damage mechanisms in air, a favored 2D lattice type will be selected for further characterization of the coating with regard to the load capacity and the corrosive properties. The aim is to establish an extensive understanding of the mechanical and corrosive properties for the simplified 2D geometry which will then be transferred towards 3D lattice structures. To characterize the application-oriented damage behavior, in-vitro corrosion fatigue tests for 3D lattice structures will be conducted. Further on, the mechanical behavior of the bone/implant interface (ex vivo) is characterized and stiffness mismatches (stress shielding) are quantified.