Acta Metallurgica Sinica (English Letters) ›› 2024, Vol. 37 ›› Issue (12): 2029-2044.DOI: 10.1007/s40195-024-01763-4

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Microstructure Evolution and High Strength-Ductility Synergy of Ti-13Nb-13Zr-2Ta Alloy Fabricated by Laser Powder Bed Fusion

Libo Zhou1,2,3(), Biao Peng1, Jian Chen1, Yanjie Ren4, Yan Niu1, Wei Qiu1, Jianzhong Tang3, Zhou Li2, Wei Chen1, Weiying Huang1, Cong Li1()   

  1. 1Institute of Energy and Power Engineering, Changsha University of Science and Technology, Changsha 410114, China
    2State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China
    3FIR Metals and Resource, LTD, Zhuzhou 412000, China
    4School of Mechanical and Energy Engineering, Zhejiang University of Science and Technology, Hangzhou 310023, China
  • Received:2024-05-21 Revised:2024-07-04 Accepted:2024-07-13 Online:2024-12-10 Published:2024-09-29
  • Contact: Libo Zhou, Libozhou@csust.edu.cn;Cong Li, liconghntu@csust.edu.cn

Abstract:

This work systematically investigates the densification, microstructure evolution and the attainment of high strength-ductility in Ti-13Nb-13Zr-2Ta alloy processed by laser powder bed fusion (LPBF). A narrow and viable process window (Plaser power = 175 W, vscanning speed = 1000 mm/s, hscanning distance = 0.1 mm and dlayer thickness = 0.03 mm) was accordingly determined and the relative density of Ti-13Nb-13Zr-2Ta alloy reaches 99.76%. The depth of molten pool increases gradually with the increase of energy density, and the relationship between the depth of molten pool and energy density has been quantitatively described. Three types of α′ martensites with average grain width less than 3 μm can be observed in the LPBF-fabricated Ti-13Nb-13Zr-2Ta alloys, attributed to the significantly high cooling rate and remelting process. The fine grain size, high density dislocations, nanotwins, ordered oxygen complexes and α + α″ heterostructure all contributed to the high strength (1037.75 ± 25.18 MPa) and ductility (20.32% ± 1.39%) of LPBF-fabricated Ti-13Nb-13Zr-2Ta alloy in this work.

Key words: Laser powder bed fusion, Ti-13Nb-13Zr-2Ta, Microstructure, Mechanical behavior