Selective laser melting enabled additive manufacturing of Ti-22Al-25Nb intermetallic: Excellent combination of strength and ductility, and unique microstructural features associated

Zhou, Y. H.1,2; Li, W. P.1,3; Wang, D. W.1,2; Zhang, L.1; Ohara, K.4; Shen, J.3; Ebel, T.5; Yan, M.1

2019-07

10.1016/j.actamat.2019.05.008

ACTA MATERIALIA   影响因子和分区

1359-6454

1873-2453

To realize near net-shaping of hard-to-process intermetallics is an often challenging but critical issue to their wider industrial applications. In this work, we report that an intermetallic Ti-22A1-25Nb has been successfully fabricated by selective laser melting (SLM). The as-printed samples show a high room temperature ultimate tensile strength similar to 1090 MPa and excellent ductility similar to 22.7%; both values are higher than most conventionally fabricated Ti-22A1-25Nb intermetallic. We clarify the mechanical performance achieved by detailed microstructure analysis, including dislocation and phase constitution. It is proposed that high-density dislocation networks significantly contribute to the strength and ductility, which are further enhanced by the favorable phase constitution, including the nano-scale O phase precipitates within the disordered beta phase and disappearance of the brittle alpha(2) phase in the microstructure. Phase evolution during solidification, particularly regarding the O phase's formation, has also been clarified using in-situ laser heating, high-temperature synchrotron X-ray diffraction and Scheil simulation. It is demonstrated that the O phase formation involves both displacive transition (B2 -> B19) and chemical ordering (B19 -> O). The metastable B19 phase (as an intermediate stage) may be formed by shearing cubic B2 phase along (110)[1 11]direction into an orthorhombic structure under high residual stress. Furthermore, a demonstrative part of turbine blade has been fabricated to highlight the importance of SLM in fabricating critical structural part like the hard-to-process intermetallics. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Ti-22Al-25Nb intermetallic Selective laser melting Dislocation Phase evolution Strengthening mechanism

SCI ; EI

英语

第一 ; 通讯

National Science Foundation of Guangdong Province[2016A030313756]

Materials Science ; Metallurgy & Metallurgical Engineering

Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering

WOS:000472812300013

PERGAMON-ELSEVIER SCIENCE LTD

20192006929646

3D printers ; Dislocations (crystals) ; Ductility ; Fabrication ; Intermetallics ; Melting ; Microstructure ; Nanotechnology ; Tensile strength ; Turbomachine blades

Metallurgy:531.1 ; Printing Equipment:745.1.1 ; Nanotechnology:761 ; Chemical Operations:802.3 ; Materials Science:951

MATERIALS SCIENCE

Web of Science

1.Southern Univ Sci & Technol, Shenzhen Key Lab Addit Mfg High Performance Mat, Dept Mat Sci & Engn, Shenzhen 518055, Peoples R China
2.Harbin Inst Technol, Sch Mat Sci & Engn, Harbin 150001, Heilongjiang, Peoples R China
3.Shenzhen Univ, Coll Mechatron & Control Engn, Shenzhen 518060, Peoples R China
4.Japan Synchrotron Radiat Res Inst SPring 8, Sayo, Miyagi 6795198, Japan
5.German Helmholtz Zentrum Geesthacht, Inst Mat Res, D-21502 Geesthacht, Germany

Zhou, Y. H.,Li, W. P.,Wang, D. W.,et al. Selective laser melting enabled additive manufacturing of Ti-22Al-25Nb intermetallic: Excellent combination of strength and ductility, and unique microstructural features associated[J]. ACTA MATERIALIA,2019,173:117-129.

Zhou, Y. H..,Li, W. P..,Wang, D. W..,Zhang, L..,Ohara, K..,...&Yan, M..(2019).Selective laser melting enabled additive manufacturing of Ti-22Al-25Nb intermetallic: Excellent combination of strength and ductility, and unique microstructural features associated.ACTA MATERIALIA,173,117-129.

Zhou, Y. H.,et al."Selective laser melting enabled additive manufacturing of Ti-22Al-25Nb intermetallic: Excellent combination of strength and ductility, and unique microstructural features associated".ACTA MATERIALIA 173(2019):117-129.