Directed energy deposition and characterization of high-carbon high speed steels

N. Ur Rahman*, L. Capuano, S. Cabeza, M. Feinaeugle, A. Garcia-Junceda, M. B. de Rooij, D.T.A. Matthews, G. Walmag, I. Gibson, G.R.B.E. Römer

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    Abstract

    Directed energy deposition (DED) of two high-carbon high speed steel alloys Febal-C-Cr-Mo-V and Febal−x-C-Cr-Mo-V-Wx was performed by using a 4 kW Nd:YAG laser source. The purpose of additive manufacturing was design and evaluation of thermally stable – high temperature wear resistant alloys. High temperature (500 °C) pin-on-disc tests were conducted to investigate the effect of carbides phase fraction on friction and wear. Strain scanning of the powder and additively manufactured materials was carried out by Neutron diffraction. Microstructures of both alloys consisted of a martensitic matrix with networks of primary and eutectic carbides. Micro-hardness (0.5 HV) measurement of all multilayer laser deposits, showed a micro-hardness greater than 700 HV, with no detrimental effect of repetitive laser thermal cycling. Febal−x-C-Cr-Mo-V-Wx showed a better high temperature wear resistance due to greater phase fraction of VC and Mo2C carbides. Fracture surfaces of post-heat treated tensile samples of Febal-C-Cr-Mo-V and Febal−x-C-Cr-Mo-V-Wx revealed brittle failures with minimal plasticity. Neutron strain mapping of the metal powders and the additively manufactured materials resulted in a weak diffraction signal and peak widening effect. These results could be explained either by an effect of strong crystallographic texture in the bulk or by the presence of nano- or semi-crystalline phases.

    Original languageEnglish
    Article number100838
    JournalAddItive manufacturing
    Volume30
    DOIs
    Publication statusPublished - 1 Dec 2019

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    Keywords

    • Additive manufacturing
    • Crystallographic texture
    • High-carbon high speed steel
    • In-situ oxidation
    • Inter-granular cracking
    • Neutron diffraction
    • Strain mapping

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