Effect of composition, annealing temperature, and high pressure torsion on structure and hardness of Ti–V and Ti–V–Al alloys

2019 ◽  
Vol 125 (8) ◽  
pp. 082522 ◽  
Author(s):  
Alena S. Gornakova ◽  
Alexandr B. Straumal ◽  
Igor I. Khodos ◽  
Ivan B. Gnesin ◽  
Andrey A. Mazilkin ◽  
...  
Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 766
Author(s):  
Boris Straumal ◽  
Askar Kilmametov ◽  
Anna Korneva ◽  
Pawel Zięba ◽  
Yuri Zavorotnev ◽  
...  

Cu–14 wt% Sn alloy was annealed at temperatures of 320 and 500 °C. The concentration of tin cinit in the copper-based matrix increased with annealing temperature. The annealed samples were subjected to high-pressure torsion (HPT) at 6 GPa, 5 turns, 1 rpa. HPT led to the refinement of Cu grains. The shape of the colonies of α + ε phases changed only slightly. The HPT-driven enrichment of the Cu-based solid solution with Sn atoms cHPT–cinit decreased with increasing cinit. The performed theoretical analysis explained this behavior of the HPT-driven enrichment.


2021 ◽  
Vol 1016 ◽  
pp. 338-344
Author(s):  
Wan Ji Chen ◽  
Jie Xu ◽  
De Tong Liu ◽  
De Bin Shan ◽  
Bin Guo ◽  
...  

High-pressure torsion (HPT) was conducted under 6.0 GPa on commercial purity titanium up to 10 turns. An ultrafine-grained (UFG) pure Ti with an average grain size of ~96 nm was obtained. The thermal properties of these samples were studied by using differential scanning calorimeter (DSC) which allowed the quantitative determination of the evolution of stored energy, the recrystallization temperatures, the activation energy involved in the recrystallization of the material and the evolution of the recrystallized fraction with temperature. The results show that the stored energy increases, beyond which the stored energy seems to level off to a saturated value with increase of HPT up to 5 turns. An average activation energy of about 101 kJ/mol for the recrystallization of 5 turns samples was determined. Also, the thermal stability of the grains of the 5 turns samples with subsequent heat treatments were investigated by microstructural analysis and Vickers microhardness measurements. It is shown that the average grain size remains below 246 nm when the annealing temperature is below 500 °C, and the size of the grains increases significantly for samples at the annealing temperature of 600 °C.


2019 ◽  
Vol 771 ◽  
pp. 317-321 ◽  
Author(s):  
Kun Xia Wei ◽  
J. Horky ◽  
Wei Wei ◽  
M.J. Zehetbauer ◽  
D. Setman ◽  
...  

2012 ◽  
Vol 66 (5) ◽  
pp. 227-230 ◽  
Author(s):  
X.H. An ◽  
S.D. Wu ◽  
Z.F. Zhang ◽  
R.B. Figueiredo ◽  
N. Gao ◽  
...  

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 181
Author(s):  
Yuanyuan Dong ◽  
Zhe Zhang ◽  
Zhihai Yang ◽  
Ruixiao Zheng ◽  
Xu Chen

316LN stainless steel is a prospective structural material for the nuclear and medical instruments industries. Severe plastic deformation (SPD) combined with annealing possesses have been used to create materials with excellent mechanical properties. In the present work, a series of ultrafine-grained (UFG) 316LN steels were produced by high-pressure torsion (HPT) and a subsequent annealing process. The effects of annealing temperature on grain recrystallization and precipitation were investigated. Recrystallized UFG 316LN steels can be achieved after annealing at high temperature. The σ phase generates, at grain boundaries, at an annealing temperature range of 750–850 °C. The dislocations induced by recrystallized grain boundaries and strain-induced nanotwins are beneficial for enhancing ductility. Moreover, microcracks are easy to nucleate at the σ phase and the γ-austenite interface, causing unexpected rapid fractures.


2016 ◽  
Vol 838-839 ◽  
pp. 287-293 ◽  
Author(s):  
Zenji Horita

Grain refinement is an important prerequisite for advent of superplasticity. In particular, as the grain size is smaller, the superplasticity appears at higher strain rates and lower temperatures. Severe plastic deformation (SPD) is a useful process for achieving significant grain refinement. This presentation shows that applicability of the SPD process is enhanced when it is operated under high pressure through high-pressure torsion (HPT) and high-pressure sliding (HPS). It is demonstrated that commercially available conventional alloys but less ductile alloys such as Mg alloys, age-hardenable high-strength Al alloys (A2024, A7075) and Ti alloys become superplastic after processing by HPT or HPS.


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