University of Oulu

Timo Rautio, Atef Hamada, Jarmo Mäkikangas, Matias Jaskari, Antti Järvenpää, Laser welding of selective laser melted Ti6Al4V: Microstructure and mechanical properties, Materials Today: Proceedings, Volume 28, Part 2, 2020, Pages 907-911, ISSN 2214-7853, https://doi.org/10.1016/j.matpr.2019.12.322

Laser welding of selective laser melted Ti6Al4V : microstructure and mechanical properties

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Author: Rautio, Timo1; Hamada, Atef1; Mäkikangas, Jarmo1;
Organizations: 1Kerttu Saalasti Institute/University of Oulu, Pajatie 5, Nivala 85500, Finland
Format: article
Version: accepted version
Access: embargoed
Persistent link: http://urn.fi/urn:nbn:fi-fe202001283688
Language: English
Published: Elsevier, 2020
Publish Date: 2022-01-16
Description:

Abstract

Ti6Al4V alloy exhibits an excellent potential for biomechanical applications as well as structural engineering applications, especially in the aerospace industry and marine applications. In this study, the effect of laser welding (LW) on grain structure and the mechanical properties in a selective laser melted (SLM) Ti6Al4V is reported. The studied material was SLMed at two different layer thicknesses t, 30 and 50 µm, and respective energy densities 69.4 and 60.3 J/mm3. Post-annealing treatment at 940 °C for 4 h was carried out to relieve stress, induce the β-phase and reduce the acicular ά martensite content, thereby helping to enhance its mechanical properties. Subsequently, LW was employed to join SLMed Ti6Al4V plates using a 2.4 kW laser travelling at 60 mm/s. The microstructures were studied as-built by SLM and after LW, followed by an evaluation of the mechanical properties. X-ray diffraction (XRD) and optical microscopy were applied for phase analysis and uniaxial tensile tests were conducted to study the joint strength. The most relevant results of the present work are that the layer thickness plays a key role on tensile properties of the SLMed Ti6Al4V. The SLMed material with t = 50 µm showed higher strength with yield strength 940 MP and ultimate strength 1130 MPa, while the corresponding properties of t = 30 µm were 910 MPa and 1080 MPa, respectively. However, the fracture elongation of the as-built materials with t = 30 µm was 15% as compared to 9% in the higher t. The tensile results of the laser welded materials did not reveal loss in the mechanical properties at both t.

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Series: Materials today. Proceedings
ISSN: 2214-7853
ISSN-E: 2214-7853
ISSN-L: 2214-7853
Volume: 28
Issue: 2
Pages: 907 - 911
DOI: 10.1016/j.matpr.2019.12.322
OADOI: https://oadoi.org/10.1016/j.matpr.2019.12.322
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Subjects:
Funding: The authors would like to acknowledge the financial support received from the Council of Oulu Region and the European Union (European Regional Development Fund) for the “Hybridi” and “Me3Lab” projects.
Copyright information: © 2020 The Authors. Published by Elsevier Inc. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/.
  https://creativecommons.org/licenses/by-nc-nd/4.0/