|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Additive Manufacturing of Metals: Fatigue and Fracture
||Fatigue Crack Growth Anisotropy in Selective Laser Melting Produced Alloy 718 at Ambient and Elevated Temperatures
||Halsey Ostergaard, Jamie J Kruzic
|On-Site Speaker (Planned)
Fatigue crack growth in alloy 718 at high temperatures and low load frequencies transitions to a time dependant, stress assisted grain boundary oxidation crack growth mechanism. Selective laser melting (SLM) produced alloy 718 parts have an epitaxial grain structure that interacts strongly with this crack growth mechanism. Compact tension samples were produced in two build orientations, and were given standard hardening heat treatments both with and without prior hot isostatic pressing. Crack growth testing was done at 25°C and 650°C in an air environment. Anisotropy in fatigue crack growth rates was found in both the transgranular and intergranular growth regimes and rates were compared with conventionally forged material. Microstructures were assessed using EBSD, and fracture surfaces and crack profiles were examined to understand the influence of microstructure and SLM specific defects on fatigue crack growth. Finally, strategies for taking advantage of crack growth anisotropy to increase part durability are discussed.
||Planned: Supplemental Proceedings volume