Title: Evolution of carbide precipitates in Haynes® 282 superalloy processed by wire arc additive manufacturing

Abstract

Precipitation hardening regulated with heat treatments is a critical technique for tuning the mechanical properties of Ni-based superalloys fabricated with additive manufacturing, where mechanical deformation is no longer viable for microstructural refinement. As one of the key precipitates, carbides prevail in the additively manufactured alloys, whose precipitation kinetics remain largely vague. This work studies the influence of heat treatments on the evolution of MC- and M₂₃C₆-type carbides within a Haynes® 282 superalloy prepared by wire arc additive manufacturing (WAAM). SEM-EDS analysis was performed to identify the evolution pathways of the carbides, and TEM and XRD characterizations were carried out to track the crystallographic features. The MC-type carbides are originally present in the as-printed alloy, which distribute uniformly across the whole material and remain largely unchanged in size during the heat treatments. By contrast, the incipiently non-existent M₂₃C₆-type carbides precipitate during an aging treatment at 1010 °C, which majorly extend along the grain boundaries as kinetically feasible sites. Further experimental and computational analysis confirms the enhancing effect of the M₂₃C₆-type carbides on the Vickers hardness. For the first time, this work revealed the evolution pathways of carbides within a Haynes® 282 superalloy prepared by WAAM, providing critical information for tunning themore » microstructure and mechanical properties. Finally, the carbide evolution kinetics established in this work can be potentially extended to other alloys prepared with WAAM, providing critical information to prevent mechanical failures associated with carbide coarsening.« less

Authors:

Zhang, Hanlei ^[1]; Wang, Yuankang ^[1]; De Vecchis, Rafael Rodriguez ^[1]; Xiong, Wei ^[1]

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+ Show Author Affiliations

1. Univ. of Pittsburgh, PA (United States)

Publication Date:

Sat Apr 09 00:00:00 EDT 2022

Research Org.:

Pennsylvania State Univ., University Park, PA (United States)

Sponsoring Org.:

USDOE Office of Fossil Energy (FE)

OSTI Identifier:

1977321

Alternate Identifier(s):

OSTI ID: 1863478

Grant/Contract Number:  

FE0026825; UCFER RFP 2020-06/DE-FE0026825

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Materials Processing Technology

Additional Journal Information:

Journal Volume: 305; Journal Issue: C; Journal ID: ISSN 0924-0136

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Engineering; Materials Science; Additive manufacturing; Superalloy; Carbide; Precipitation; Grain boundary