Author(s): Emiel Amsterdam; Ali Chabok
|
Multi-disciplinary design optimization and novel manufacturing technologies like additive manufacturing have provided designers with tools to create highly optimized structures as well as the ability to fabricate them. The introduction of ICME and hierarchical bioinspired architected materials require relationships between the microstructure and mesostructure of materials and the performance of materials in terms of failure mechanisms (e.g., fatigue).
Citation:
ABSTRACT
Topology optimization and novel manufacturing technologies like additive manufacturing (AM) have provided designers with the tools to manufacture highly optimized components. However, these components require an understanding of relationships between the microstructure and mesostructure of the materials from which they are built, and the performance in terms of fatigue. Many microstructure-property relationships focus on the relationship between the microstructure and the quasi-static mechanical properties. However, accurate physical models that relate the fatigue properties to the microstrucuture and mesostructure of materials such as metallic AM alloys are lacking. The current study focuses on the effect of the microstrucuture and mesostructure of additively manufactured materials on fatigue properties. In particular, a fracture-mechanics-informed phenomenological model is introduced that accurately describes the influence of the initial discontinuity size, the applied maximum cyclic stress, and the ultimate tensile strength on the high cycle fatigue life of AlSi10Mg and Ti-6Al-4V made by laser powder bed fusion. The effect of the mesostructure on load re-distribution and crack re-nucleation during fatigue loading was investigated using stretch-dominated multiple load path specimens of AlSi10Mg and Ti-6Al-4V that were tested in the as-built surface condition. The results show that the multiple load path structures are more damage tolerant, but have an overall lower fatigue life.
