Creep behaviour and superplasticity in UFG Ti-6Al-4V alloy

0450341 - ÚFM 2016 RIV CZ eng A - Abstract
Král, Petr - Dvořák, Jiří - Kudrjavtsev, E. - Zherebtsov, S. - Salishchev, G. A. - Kvapilová, Marie - Sklenička, Václav
Creep behaviour and superplasticity in UFG Ti-6Al-4V alloy.
Book of Abstracts. 17th International Conference on the Strength of Materials (ICSMA-17). Brno: Ústav fyziky materiálů AV ČR, v. v. i., 2015 - (Dlouhý, A.; Kunz, L.). s. 230-230. ISBN 978-80-87434-07-9.
[ICSMA-17 International Conference on the Strength of Materials /17./. 09.08.2015-14.08.2015, Brno]
Institutional support: RVO:68081723
Keywords : creep behaviour * superplasticity * microstructure * ultrafine-grained alloy
Subject RIV: JJ - Other Materials

In this paper, the creep behaviour of a Ti-6Al-4V alloy processed by multiaxial forging was investigated. The originally as-received coarse –grained titanium alloy was processed by multiaxial forging in the temperature range from 973 to 748 K. The initial strain rate was 10-3 s-1 strain per deformation step was about 0.5. Ultrafine-grained Ti alloy with mean grain size d~150 nm was tested at 648-873 K at constant stress in compression and under constant load in tension. The values of the stress exponent of the minimum creep rate n and creep activation energy Qc were determined. The microstructure of specimens after creep testing was examined by FIB/SEM Tescan Lyra 3 equipped with NordlysNano EBSD detector operating at an accelerating voltage of 20 kV with specimen tilted at 70°. The EBSD analyses of both gauge length and head of specimens were performed in the longitudinal sections parallel to the stress direction. The results of the uniaxial creep tests showed different values of the stress exponents of the minimum creep rate n at 673 K and 873 K. The values of creep activation energy Qc indicated the change of creep deformation mechanism above 773 K.
Permanent Link: http://hdl.handle.net/11104/0251714