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

该子项目的总体目标是对通过PBF-LB/M制造的涂层Ti-6Al-4V晶格结构在循环载荷以及腐蚀暴露下的微观和机械变形和损伤行为进行整体表征。由于复杂的情况下，加载条件将首先被视为单独的，然后集体，以检测占主导地位的机制，分别。在确定PBF-LB/M工艺参数的影响，通过执行时间有效的腐蚀和准静态测试，最佳的参数集被定义为用于制造简化的2D几何形状的基础上三重周期最小曲面（TPMS）。从疲劳强度和在空气中的循环损伤机制，一个有利的2D晶格类型将被选择用于进一步表征涂层的负载能力和腐蚀性能。其目的是建立一个广泛的理解的机械和腐蚀性能的简化的2D几何形状，然后将转移到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。此外，表征骨/植入物界面（离体）的机械行为，并量化刚度失配（应力遮挡）。

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.