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This document is downloaded from DR‑NTU (https://dr.ntu.edu.sg) Nanyang Technological University, Singapore. Selective electron beam melting of Co‑Cr‑Mo : microstructure and mechanical properties Tan, Xipeng; Wang, Pan; Nai, Sharon; Liu, Erjia; Tor, Shu Beng 2018 Tan, X., Wang, P., Nai, S., Liu, E., & Tor, S. B. (2018). Selective electron beam melting of Co‑Cr‑Mo : microstructure and mechanical properties. Proceedings of the 3rd International Conference on Progress in Additive Manufacturing (Pro‑AM 2018), 535‑540. doi:10.25341/D4201S https://hdl.handle.net/10356/88877 https://doi.org/10.25341/D4201S © 2018 Nanyang Technological University. Published by Nanyang Technological University, Singapore. Downloaded on 07 Apr 2021 03:08:12 SGT
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SELECTIVE ELECTRON BEAM MELTING OF CO-CR-MO ... · Selective electron beam melting (SEBM) is a promising powder-bed fusion additive manufacturing (AM) technology for metals and alloys,

Oct 23, 2020

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  • This document is downloaded from DR‑NTU (https://dr.ntu.edu.sg)Nanyang Technological University, Singapore.

    Selective electron beam melting of Co‑Cr‑Mo :microstructure and mechanical properties

    Tan, Xipeng; Wang, Pan; Nai, Sharon; Liu, Erjia; Tor, Shu Beng

    2018

    Tan, X., Wang, P., Nai, S., Liu, E., & Tor, S. B. (2018). Selective electron beam melting ofCo‑Cr‑Mo : microstructure and mechanical properties. Proceedings of the 3rd InternationalConference on Progress in Additive Manufacturing (Pro‑AM 2018), 535‑540.doi:10.25341/D4201S

    https://hdl.handle.net/10356/88877

    https://doi.org/10.25341/D4201S

    © 2018 Nanyang Technological University. Published by Nanyang Technological University,Singapore.

    Downloaded on 07 Apr 2021 03:08:12 SGT

  • ABSTRACT: As an emerging powder-bed fusion additive manufacturing technique, selective electron beam melting (SEBM) attracts numerous attentions due to its great potential applications in orthopaedic implants and aerospace components. The microstructure and mechanical properties of SEBM-built Co-Cr-Mo alloy have been investigated. Microstructural characterisation was carried out using scanning electron microscopy, and X-ray diffraction techniques. Its microstructure consists of face-centred cubic columnar grains with preferred orientation and continuous carbide thin films at grain boundaries. Each columnar grain is comprised of parallel dendrites with short secondary arms and sparse carbides within interdendritic regions. Two sorts of carbides were identified in terms of their compositions, i.e. C23M6 and C6M (where M = Co, Cr and Mo). In addition, anisotropic mechanical properties were found to exist in SEBM-built Co-Cr-Mo parts. The microstructure-property relationship for SEBM-built Co-Cr-Mo parts is discussed. KEYWORDS: additive manufacturing, EBM, Co-Cr-Mo alloy, microstructure, mechanical properties

    INTRODUCTION

    Selective electron beam melting (SEBM) is a promising powder-bed fusion additive manufacturing (AM) technology for metals and alloys, and it is being increasingly used in producing complex orthopeadic implants and aerospace components (Tan et al. 2014; Kok et al. 2015). In addition to some process-induced defects, such as internal pores and rough surface, another critical issue that may obstacle its wide applications is the limited material library for SEBM process. Ti-6Al-4V is still the most investigated material in SEBM and its microstructure and mechanical properties have been extensively reported [Wang et al. 2016; Tan et al. 2015; Tan et al. 2016]. However, only limited studies were involved in SEBM processing of Co-Cr-Mo alloys [Kircher et al. 2009; Gaytan et al. 2010; Sun et al. 2014; Sun et al. 2015; Kok et al. 2018; Tan et al. 2018]. Co-Cr-Mo alloys are widely used in both biomedical and aerospace applications where require good biocompatibility, high wear resistence, and superior high-temperature creep properties [Davis 2000].

    In recent years, microstructural consistency, i.e. anisotropy and homogeneity of microstructure, has become another important concern when seeking practical applications of SEBM as well as other metal AM techniques. Sun et al. [Sun et al. 2014] reported the build direction and build height dependent microstructure and their effects on high-temperature tensile and creep properties for SEBM-built Co-Cr-Mo. Kircher et al. [Kircher et al. 2009] suggested that as-SEBM-built Co-Cr-Mo has significantly better mechanical properties as compared to its wrought and as-cast forms. The SEBM-built Co-Cr-Mo, however, was found to be more brittle with a markedly lower elongation before failure. This is especially so when the load was applied normal to the z-direction

    SELECTIVE ELECTRON BEAM MELTING OF CO-CR-MO: MICROSTRUCTURE AND MECHANICAL PROPERTIES

    XIPENG TAN1, PAN WANG2, SHARON NAI2, ERJIA LIU1, SHU BENG TOR1 1Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang

    Technological University, 50 Nanyang Avenue, Singapore 639798 2 Singapore Institute of Manufacturing Technology, 73 Nanyang Drive, Singapore 637662

    535

    Proc. Of the 3rd Intl. Conf. on Progress in Additive Manufacturing (Pro-AM 2018) Edited by Chee Kai Chua, Wai Yee Yeong, Ming Jen Tan, Erjia Liu and Shu Beng TorCopyright © 2018 by Nanyang Technological UniversityPublished by Nanyang Technological University ISSN: 2424-8967 :: https://doi.org/10.25341/D4201S

  • Chee Kai Chua, Wai Yee Yeong, Ming Jen Tan, Erjia Liu and Shu Beng Tor (Eds.)

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  • Proc. Of the 3rd Intl. Conf. on Progress in Additive Manufacturing

    537

  • Chee Kai Chua, Wai Yee Yeong, Ming Jen Tan, Erjia Liu and Shu Beng Tor (Eds.)

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  • Proc. Of the 3rd Intl. Conf. on Progress in Additive Manufacturing

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  • Kok, Y., Tan, X.P., Tor, S.B., & Chua, C.K. (2015). Fabrication and microstructural characterisation of additive manufactured Ti-6Al-4V parts by electron beam melting. Virtual and Physical Prototyping, 10(1), 13-21.

    Wang, P., et al. (2016). Recent progress of additive manufactured Ti-6Al-4V by electron beam melting. In Proceedings of the 2016 Annual International Solid Freeform Fabrication Symposium (SFF Symp 2016), Austin: Univ. Tex., 691-704.

    Tan, X.P., et al. (2015). Graded microstructure and mechanical properties of additive manufactured Ti–6Al–4V via electron beam melting. Acta Materialia, 97, 1-16.

    Tan, X.P., et al. (2016). Revealing martensitic transformation and / interface evolution in electron beam melting three-dimensional-printed Ti-6Al-4V. Scientific Reports, 6, 26039.

    Kircher, R. S., Christensen, A. M., & Wurth, K. W. (2009). Electron beam melted (EBM) Co-Cr-Mo alloy for orthopaedic implant applications. In Solid Freeform Fabrication Proceedings. Austin: Univ. Tex. 428-436.

    Gaytan, S. M., et al. (2010). Comparison of microstructures and mechanical properties for solid and mesh cobalt-base alloy prototypes fabricated by electron beam melting. Metallurgical and Materials Transactions A, 41(12), 3216-3227.

    Sun, S. H., Koizumi, Y., Kurosu, S., Li, Y. P., Matsumoto, H., & Chiba, A. (2014). Build direction dependence of microstructure and high-temperature tensile property of Co–Cr–Mo alloy fabricated by electron beam melting. Acta Materialia, 64, 154-168.

    Sun, S. H., Koizumi, Y., Kurosu, S., Li, Y. P., & Chiba, A. (2015). Phase and grain size inhomogeneity and their influences on creep behavior of Co–Cr–Mo alloy additive manufactured by electron beam melting. Acta Materialia, 86, 305-318.

    Kok, Y., et al. (2018). Anisotropy and heterogeneity of microstructure and mechanical properties in metal additive manufacturing: A critical review. Materials & Design, 139, 565-586.

    Tan, X. P., et al. (2018). Carbide precipitation characteristics in additive manufacturing of Co-Cr-Mo alloy via selective election beam melting. Scripta Materialia, 143, 117-121.

    Davis, J. R. (Ed.). (2000). Nickel, cobalt, and their alloys. ASM international.

    Chee Kai Chua, Wai Yee Yeong, Ming Jen Tan, Erjia Liu and Shu Beng Tor (Eds.)

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