Microstructural influences on fatigue crack initiation and early propagation in Ni-based superalloy

Kim, Donghyuk, Jiang, Rong, Sinclair, Ian and Reed, Philippa (2022) Microstructural influences on fatigue crack initiation and early propagation in Ni-based superalloy. Materials Science and Technology, 38 (14), 1081 - 1094.

Record type: Article

Abstract

Effects of unimodal secondary γ′ size and grain orientation on fatigue crack initiation and early crack propagation at room temperature have been investigated in RR1000 alloy. Fatigue tests show cracks mainly initiated at slip bands and/or pores followed by crystallographic facet formation while more diffuse strain localisation is observed around the pores by SEM-DIC analysis. Fatigue lifetime is linked to the number of crack initiations and consequent crack coalescence, which accelerates crack propagation. Slip trace analysis with EBSD mapping shows cracks are likely to propagate along the primary active slip system with a relatively high Schmid Factor. In the tests conducted here, the stochasticity of crack initiation events has more control on the overall lifetime than variations in secondary γ′ size.

Text

Microstructural influences on fatigue crack initiation and early propagation in Ni based superalloy (1) - Version of Record

Restricted to Repository staff only

Request a copy

Text

Microstructural influences

Available under License Creative Commons Attribution Non-commercial.

Download (11MB)