Microstructures analysis and quantitative strengthening evaluation of powder metallurgy Ti-Fe binary extruded alloys with (α plus β)-dual-phase

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:803

Article

Umeda, Junko¹  Tanaka, Takayuki¹  Teramae, Takuma¹  Kariya, Shota¹  Fujita, Junji¹  Nishikawa, Hiroshi¹  Shibutani, Yoji²  Shen, Jianghua³  Kondoh, Katsuyoshi¹ 

[1] Osaka Univ, Joining & Welding Res Inst, 11-1 Mihogaoka, Ibaraki, Osaka 5670047, Japan

[2] Osaka Univ, Dept Mech Engn, 2-1 Yamadaoka, Suita, Osaka 5650871, Japan

[3] Northwestern Polytech Univ, Dept Aeronaut Struct Engn, Xian 710072, Shaanxi, Peoples R China

关键词: Titanium alloys;    Powder metallurgy;    Solid solution;    Grain refinement;    Phase transformation;    Strengthening behavior;   

DOI  :  10.1016/j.msea.2020.140708

来源: Elsevier

【 摘 要 】

In this study, Fe, one of the inexpensive beta-phase stabilizers, was employed to fabricate Ti alloys by the powder metallurgy route. The formation mechanism of unique microstructures and texture of the extruded Ti-Fe alloy was elucidated through scanning electron microscopy-electron backscatter diffraction (SEM-EBSD) and transmission electron microscopy-energy-dispersive X-ray spectroscopy (TEM-EDS). For the Ti-Fe alloys consolidated from the pre-mixed pure Ti powder and Fe particles by spark plasma sintering and following hot extrusion, the additive Fe atoms existed as solid solution atoms in beta-Ti phase. The increment in the Fe content was effective in increasing the beta-Ti phase volume fraction and refining the alpha-Ti grains. The mean alpha-Ti grain size of Ti-4 wt.% Fe alloy was 1.27 mu m, which was about ten times less than that of the pure Ti material (12.42 mu m). The alpha and beta phases of the extruded Ti-1-4 wt.% Fe material were aligned in parallel to the extrusion direction, and they suppressed the grain growth of each other. Although yield stress (YS) and tensile strength (TS) remarkably increased to 1093 MPa and 1183 MPa, respectively, with an increase in the Fe content, a large elongation of 28-38% was obtained in the extruded Ti-Fe alloys. These tensile properties were favorable compared to the commercial Ti-6 wt.% Al-4 wt.% V alloy. The dominant strengthening factors for the Ti-Fe alloys were alpha-Ti grain refinement and beta-Ti hard phase dispersion. In the case of 4 wt% Fe addition, 50% of the YS increment was due to the latter strengthening mechanism.

【 授权许可】

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