Creep performance of a standard and modified version of laser powder bed fusion-processed Haynes 230

Abstract

Haynes 230 is a solid solution and carbide precipitation strengthened nickel alloy often used in gas turbine engines. While the alloy is arc weldable, efforts to introduce the alloy to laser powder bed fusion additive manufacturing have been hindered by the presence of solidification cracking which severely debits mechanical properties. In this study, the creep performance of standard laser powder bed fusion processed Haynes 230 at 760 °C is compared to a modified, crack-free version of the alloy. The modified version of Haynes 230 exhibits lower minimum creep rates, higher creep ductilities, and longer rupture times compared to standard Haynes 230. Analysis using a creep rupture time model indicates that the primary factor leading to the longer creep life in the modified Haynes 230 is the lower minimum creep rate, attributed largely to an increased quantity of carbide precipitates, though the finer grain size in the modified alloy also made a small contribution. Due to the increases in creep performance, the modified version of the alloy shows similar creep behavior to wrought Haynes 230, while the standard version of the alloy shows considerably degraded creep performance. The results of this work show that minor compositional and microstructural modification is a meritorious pathway to manufacture legacy alloys with novel techniques such that the advantages which additive manufacturing offers, like increased component complexity and part consolidation, can be realized without developing new alloy systems.