Fracture toughness anisotropy of Ti17 billet processed by the β forging

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

卷:807

Article

Chen, Wei^1,2,3  Zeng, Weidong^1,2,3  Zhao, Yaohua^1,2,3  Gao, Pan^1,2,3  Xu, Jianwei^1,2,3  Zhao, Qinyang⁴ 

[1] Northwestern Polytech Univ, State Key Lab Solidificat Proc, Sch Mat Sci & Engn, Xian 710072, Peoples R China

[2] Northwestern Polytech Univ, Def Technoloies Innovat Ctr Precis Forging & Ring, Sch Mat Sci & Engn, Xian 710072, Peoples R China

[3] Northwestern Polytech Univ, Shaanxi Key Lab High Performance Precis Forming T, Xian 710072, Peoples R China

[4] Changan Univ, Sch Mat Sci & Engn, Xian 710064, Peoples R China

关键词: Titanium alloy;    β forging;    Fracture toughness;    Anisotropy;    Delamination;   

DOI  :  10.1016/j.msea.2021.140825

来源: Elsevier

【 摘 要 】

The fracture behavior of Ti17 billet processed by the beta forging was examined. The results demonstrate that the specimen orientation has a pronounce effect on the fracture toughness value as well as on the crack propagation path. The fracture anisotropy can be attributed to the elongated and aligned beta grain. The crack preferentially nucleates and propagates along the precipitate-free zone nearby the grain boundary. It causes either crack deflection or delamination, enhancing the fracture resistance as compared to one weak specimen orientation. The exceptionally good combination of strength and fracture toughness can be achieved by activating delamination toughening. The delamination transforms the fracture under plane-strain condition into a series of fracture processes in plane-stress condition through the thickness, and the fracture toughness is enhanced. Furthermore, a fracture toughness prediction model considering both the intrinsic and extrinsic contributions is constructed. The results show that the extrinsic toughness varies greatly than the intrinsic toughness in different orientations, indicating that the extrinsic toughness plays a significant role in the fracture toughness anisotropy of the Ti17 billet.

【 授权许可】

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