Investigation of the effects of stresses on the formation of ω-phase crystals in β-titanium alloys

2022 ◽  
pp. 569-572
Author(s):  
E. Sukedai ◽  
H. Nishizawa ◽  
J. Okuhara ◽  
H. Hashimoto
Keyword(s):  
Titanium Alloys ◽  
Ω Phase

High-resolution EM investigation about effect of stress on formation of ω-phase crystals in β-tttanium alloys

1996 ◽  
Vol 54 ◽  
pp. 1006-1007
Author(s):  
E. Sukedai ◽  
M. Shimoda ◽  
A. Fujita ◽  
H. Nishizawa ◽  
H. Hashimoto
Keyword(s):  
High Resolution ◽  
Titanium Alloys ◽  
High Resolution Electron Microscopy ◽  
Dark Field ◽  
Zone Refining ◽  
Ω Phase ◽  
Α Phase ◽  
Nucleation Sites ◽  
Resolution Electron ◽  
Bcc Structure

ω-phase particles formed in β-titanium alloys (bcc structure) act important roles to their mechanical properties such as ductility and hardness. About the ductility, fine ω-phase particles in β–titanium alloys improve the ductility, because ω-phase crystals becomes nucleation sites of α-phase and it is well known that (β+α) duplex alloys have higher ductility. In the present study, the formation sites and the formation mechanism of ω-phase crystals due to external stress and aging are investigated using the conventional and high resolution electron microscopy.A β-titanium alloy (Til5Mo5Zr) was supplied by Kobe Steel Co., and a single crystal was prepared by a zone refining method. Plates with {110} surface were cut from the crystal and were pressured hydrostatically, and stressed by rolling and tensile testing. Specimens for aging with tensile stress were also prepared from Ti20Mo polycrystals. TEM specimens from these specimens were prepared by a twin-jet electron-polishing machine. A JEM 4000EX electron microscope operated at 400k V was used for taking dark field and HREM images.

scholarly journals Exploration of Nano-scale Structural Instabilities in Metastable β Titanium Alloys Using Advanced Electron Microscopy

2020 ◽  
Vol 321 ◽  
pp. 12001
Author(s):  
Yufeng Zheng ◽  
Dong Wang ◽  
Rajarshi Banerjee ◽  
Dipankar Banerjee ◽  
Yunzhi Wang ◽  
...  
Keyword(s):  
Titanium Alloys ◽  
Mechanical Performance ◽  
Advanced Characterization ◽  
Hexagonal Structure ◽  
Experimental Conditions ◽  
Nano Scale ◽  
Ω Phase ◽  
Transformation Mechanisms ◽  
Structural Instabilities ◽  
O Phase

A variety of nano-scale structural instabilities formed in different metastable β titanium alloys have been systematically investigated using advanced characterization techniques. The characteristics of three different types of nano-scale structural instabilities, the transformation mechanisms and pathways involved and the critical experimental conditions to generate such nano-scale phases will be reviewed and summarized, including athermal ω phase with hexagonal structure, O’ phase with orthorhombic structure, and incommensurate modulated nanodomains. The athermal ω phase has been observed in the as-quenched state in Ti-xMo (x=12, 15 and 181), Ti-18Mo-5Al, Ti-20V, Ti-5Fe, Ti-5Al-5Mo-5V-3Cr (Ti-5553) and Ti-24Nb-4Zr-8Sn (Ti-2448). O’ phase has been characterized to co-exist with athermal ω phase in the as-quenched state isomorphous titanium alloys, including Ti-26Zr-2Al (at.%), Ti-18Mo, Ti-18Mo-5Al, Ti-5553 and Ti-2448. Incommensurate modulated nanodomains were found in compositionally graded Ti-xFe alloy when the athermal ω phase is suppressed. These various nano-scale structural instabilities need to be taken into consideration when designing novel metastable β titanium alloys to optimize the mechanical performance by microstructure engineering.

Surface Effect in a Metastable β Ti-Nb-Sn Alloy

2021 ◽  
Vol 1035 ◽  
pp. 562-567
Author(s):  
Li Chun Qi ◽  
Wen Xiao Qu ◽  
Yong Qi Zhu ◽  
Qing Liu
Keyword(s):  
Titanium Alloys ◽  
Orientation Relationship ◽  
Surface Effect ◽  
Phase Region ◽  
Martensite Phase ◽  
The Other ◽  
Β Phase ◽  
Ω Phase

The phase compositions of surface and interior in Ti-32Nb-4Sn metastable b alloy were investigated. It was found that this alloy exhibits surface effect significantly different from the effects reported in Ti-10V-2Fe-3Al, Ti-22Nb-9Zr and the other titanium alloys. The surface of Ti-32Nb-4Sn specimen quenched from single b phase region was characterized by dominant b phase and a few of α″ and ω phase. While in the interior of the alloy, a large amount of α² martensite phase was observed in addition to b phase The orientation relationship between the α″ martensite and β phase is (110)β∥(002)α″, (020)β∥(022)α″ and [001]β∥[100]α″.

Revisiting ω phase embrittlement in metastable β titanium alloys: Role of elemental partitioning

2021 ◽  
Vol 193 ◽  
pp. 38-42
Author(s):  
M.J. Lai ◽  
T. Li ◽  
F.K. Yan ◽  
J.S. Li ◽  
D. Raabe
Keyword(s):  
Titanium Alloys ◽  
Ω Phase

Suppression of isothermal ω phase by dislocation tangles and grain boundaries in metastable β-type titanium alloys

2013 ◽  
Vol 550 ◽  
pp. 35-38 ◽  
Author(s):  
Shun Guo ◽  
Qingkun Meng ◽  
Liang Hu ◽  
Guangyue Liao ◽  
Xinqing Zhao ◽  
...  
Keyword(s):  
Titanium Alloys ◽  
Grain Boundaries ◽  
Ω Phase

scholarly journals The indirect influence of the ω phase on the degree of refinement of distributions of the α phase in metastable β-Titanium alloys

2016 ◽  
Vol 103 ◽  
pp. 165-173 ◽  
Author(s):  
Yufeng Zheng ◽  
Robert E.A. Williams ◽  
John M. Sosa ◽  
Talukder Alam ◽  
Yunzhi Wang ◽  
...  
Keyword(s):  
Titanium Alloys ◽  
Indirect Influence ◽  
Ω Phase ◽  
Α Phase

On the completeness of the β→ω transformation in metastable β titanium alloys

2017 ◽  
Vol 50 (1) ◽  
pp. 283-287 ◽  
Author(s):  
Jana Šmilauerová ◽  
Petr Harcuba ◽  
Dominik Kriegner ◽  
Václav Holý
Keyword(s):  
Single Crystal ◽  
Titanium Alloys ◽  
Radial Profile ◽  
Diffraction Maximum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase ◽  
Ω Phase ◽  
Diffraction Peaks ◽  
Integrated Intensities

The completeness of the β→ω transformation in ω particles in a Ti–8 at.%Mo (Ti–15 wt%Mo) single crystal was investigated by measuring the X-ray diffraction maximum 20{\overline 2}2, which is forbidden in both the pure body-centred cubic β phase and the hexagonal ω phase, and also the diffraction maxima 0001, 0002 and 10{\overline 1}1, which are forbidden in the β phase and allowed in ω. From a comparison of the integrated intensities and widths of the diffraction peaks with simulations, the effective (mean) degree of the transformation was determined and the radial profile of the transformation degree in an ω particle was estimated.

Non-isothermal phase transformation kinetics of ω phase in TB-13 titanium alloys

2010 ◽  
Vol 527 (20) ◽  
pp. 5100-5104 ◽  
Author(s):  
Zhongbo Zhou ◽  
Minjie Lai ◽  
Bin Tang ◽  
Hongchao Kou ◽  
Hui Chang ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Titanium Alloys ◽  
Transformation Kinetics ◽  
Ω Phase ◽  
Phase Transformation Kinetics ◽  
Kinetics Of
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