Factors influencing superplasticity in the Ti-6Al-4V alloy Processed by high-pressure torsion

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

卷:718

Article

Shahmir, Hamed¹  Naghdi, Fariba¹  Pereira, Pedro Henrique R.¹  Huang, Yi¹  Langdon, Terence G.¹ 

[1] Univ Southampton, Mat Res Grp, Facil Engn & Environm, Southampton SO17 1BJ, Hants, England

关键词: High-pressure torsion;    Phase transformation;    Severe plastic deformation;    Superplasticity;    Ti-6Al-4V alloy;   

DOI  :  10.1016/j.msea.2018.01.091

来源: Elsevier

【 摘 要 】

Two different initial microstructures, martensitic and lamellar, were developed in a Ti-6Al-4V alloy to examine their effect on the high temperature mechanical properties and superplasticity after high-pressure torsion (HPT). Significant grain refinement was achieved in both conditions with grain sizes after HPT processing of similar to 30 and similar to 40 nm, respectively. The nanocrystalline alloy in both conditions was subjected to mechanical testing at 923-1073 K with strain rates in the range from 10(-3) to 10(-1) s(-1). The martensitic and lamellar alloys exhibited excellent ductility at these high temperatures including superplastic elongations at 973 K with maximum elongations of 815% and 690%, respectively. The fcc phase was stable at elevated temperatures in the martensitic alloy and the results suggests the fcc phase may contribute to the superior superplastic properties of the martensitic alloy.

【 授权许可】

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