Acta Metallurgica Sinica (English Letters) ›› 2020, Vol. 33 ›› Issue (12): 1601-1608.DOI: 10.1007/s40195-020-01115-y

Previous Articles     Next Articles

Typical Microstructural Characteristics of Ti-5Al-5Mo-5V-3Cr-1Fe Metastable β Ti Alloy Forged in α+β Region

Zhiying Zheng1, Linjiang Chai1(), Kang Xiang1, Weijiu Huang2(), Yongfeng Wang3, Liangliang Liu3, Lin Tian3   

  1. 1College of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China
    2College of Materials Science and Engineering, Chongqing University of Arts and Sciences, Chongqing, 402160, China
    3Chongqing Kingsley Aeronautical Material Technology Co. Ltd, Chongqing, 404100, China
  • Received:2020-02-25 Revised:2020-04-23 Accepted:2020-05-24 Online:2020-12-10 Published:2020-12-11
  • Contact: Linjiang Chai,Weijiu Huang

Abstract:

In this study, typical microstructural characteristics of a metastable β Ti alloy (Ti-5Al-5Mo-5V-3Cr-1Fe) forged in a dual-phase region (strain of 54% at 820 °C) were investigated in detail by the combined use of X-ray diffraction, energy dispersive spectroscopy, electron channeling contrast imaging and electron backscatter diffraction techniques. Results show that the microstructure of the forged alloy is composed of bulk α grains, α plates and β matrix. The bulk α grains correspond to retained primary α phase (αp, average grain size~2.4 μm), while the α plates are secondary α phase (αs, width~70 nm) precipitated from the β matrix during air cooling. During forging, the β matrix experiences dynamic recovery with many subgrains and significant orientation gradients formed. Analyses of the orientation relationship between the α and β phases show that the Burgers orientation relationship is not maintained between some αp and β phases, which should be related to thermal deformation-induced changes of their orientations. In contrast, all of the αs plates are found to maintain well the Burgers orientation relationship with the β phase.

Key words: Metastable β Ti alloy, α+β forging, Dynamic recovery, Orientation relationship, Electron backscatter diffraction (EBSD)