An Analytical Creep Rupture Time Model for Wrought, Cast, and Gas Metal Arc Directed Energy Deposition Haynes 282

Abstract Haynes 282 is a gamma prime strengthened Ni-based superalloy that is employed for high temperature structural applications such as valves and piping in power generation. Haynes 282 is often used in wrought or cast forms to fabricate a variety of components. When components in power plants fail unexpectedly, additive manufacturing can provide the accelerated manufacturing times needed to quickly produce replacement parts. In this work, we evaluate the creep performance of Haynes 282 produced with high deposition rate gas metal arc directed energy deposition (GMA-DED). A Fronius TPS 400i gas metal arc welding (GMAW) heat source using the pulse deposition mode was used to produce wall builds. The builds were direct single step aged at 800 °C for 8 hours (as developed by Haynes for large components), and samples were extracted parallel and perpendicular to the build direction. Both orientations of the GMA-DED samples were then creep tested at 325, 350, and 375 MPa at 760 °C to failure. The stress exponents from the GMA-DED creep data were analyzed and compared to wrought and cast data showing similar creep mechanisms are dominant in all evaluated forms of the alloy. An analytical creep rupture time model was applied to wrought and cast Haynes 282 data acquired from literature and to the GMA-DED results generated in this work. In general, the model predictions match experimental life data well from wrought, cast, and GMA-DED Haynes 282. Furthermore, the creep behavior of GMA-DED falls between that of wrought and cast Haynes 282. GMA-DED does exhibit a combination of transgranular and intergranular creep fracture, which has not been reported with wrought or cast Haynes 282. This work highlights that GMA-DED has great potential to produce large structural components for creep limited applications, but additional work is needed to understand the deformation mechanisms operative under a wide range of loading conditions.