Formation mechanism of α lamellae during β→α transformation in polycrystalline dual-phase Ti alloys

2021 ◽  
Vol 71 ◽  
pp. 98-108
Author(s):  
Jia Sun ◽  
Min Qi ◽  
Jinhu Zhang ◽  
Xuexiong Li ◽  
Hao Wang ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Dual Phase ◽  
Ti Alloys

New insights into formation mechanism of interfacial twin boundary ω-phase in metastable β-Ti alloys

2020 ◽  
Vol 164 ◽  
pp. 110363 ◽  
Author(s):  
Wei Chen ◽  
Shuo Cao ◽  
Jinyu Zhang ◽  
You Zha ◽  
Qingmiao Hu ◽  
...  
Keyword(s):  
Twin Boundary ◽  
Formation Mechanism ◽  
Ti Alloys ◽  
Ω Phase

Investment Casting of Ti Alloys for Biomedical Application

2006 ◽  
Vol 510-511 ◽  
pp. 794-797
Author(s):  
Si Young Sung ◽  
Young Jig Kim
Keyword(s):  
Formation Mechanism ◽  
Biomedical Application ◽  
Melting Furnace ◽  
Formation Mechanisms ◽  
Interstitial Oxygen ◽  
Reaction Products ◽  
Thermodynamic Consideration ◽  
Electron Probe Micro Analyzer ◽  
Ti Alloys ◽  
Net Shape Forming

The aim of this study is to clarify the alpha-case formation mechanisms for the economic net-shape forming of Ti and Ti alloys. The α-case formation reaction between Ti and Al2O3 mold was examined in a plasma arc melting furnace. The reaction products were characterized by using an electron probe micro-analyzer and transmission electron microscopy. The α-case generation between Ti and Al2O3 mold could not be explained by the conventional α-case formation mechanism, which is known to be formed by the interstitials, especially oxygen dissolved from mold materials. However, on the basis of our experimental results and thermodynamic consideration, it was confirmed that the α-case is formed not only by interstitial oxygen atoms but also by substitutional metal atoms dissolved from mold materials. Based on the α-case formation mechanism, α-case free net-shape forming of Ti and Ti alloys could be possible for biomedical applications.

scholarly journals Design and development of a dual-phase TRIP-TWIP alloy for enhanced mechanical properties

2020 ◽  
Vol 321 ◽  
pp. 11014
Author(s):  
Lola Lilensten ◽  
Yolaine Danard ◽  
Fan Sun ◽  
Philippe Vermaut ◽  
Loïc Perrière ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Single Phase ◽  
Second Phase ◽  
Dual Phase ◽  
Body Centered Cubic ◽  
Transformation Induced Plasticity ◽  
Ti Alloys ◽  
Semi Empirical ◽  
Alloy Analysis

Triggering transformation induced plasticity (TRIP) and twinning induced plasticity (TWIP) mechanisms in metastable β titanium alloys (bcc, body centered cubic) have helped reaching unprecedented mechanical properties for Ti-alloys, including high ductility and work-hardening. Yet the yield strength of such alloys generally remains rather low. So far, mostly single-phase metastable bcc alloys have been developed. In this study, a dual phase TRIP/TWIP alloy is designed and investigated. While the β-matrix is expected to display TRIP/TWIP deformation mechanisms, the addition of a second phase, α in the present study, aims at increasing the yield strength. The composition was designed in the Ti-Cr-Sn system, based on Calphad prediction and on the semi-empirical d-electron alloy design approach. Results were compared to the published full β Ti – 8.5Cr – 1.5Sn (wt%) TRIP/TWIP alloy. The dual-phase alloy was prepared and processed to reach the desired microstructure containing about 20% α. It displays remarkable mechanical properties such as a ductility of 29%, an ultimate tensile strength of 1200 MPa and a yield strength of 760 MPa, 200MPa higher than the Reference single-phase β alloy. Analysis of the mechanical properties and deformation microstructures confirm the TRIP and TWIP effects, validating the proposed approach.

scholarly journals Microstructure globularization of high oxygen concentration dual-phase extruded Ti alloys via powder metallurgy route

2021 ◽  
Vol 172 ◽  
pp. 110855
Author(s):  
Abdollah Bahador ◽  
Junko Umeda ◽  
Hamidreza Ghandvar ◽  
Tuty Asma Abu Bakar ◽  
Ridvan Yamanoglu ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Oxygen Concentration ◽  
High Oxygen ◽  
Dual Phase ◽  
High Oxygen Concentration ◽  
Ti Alloys ◽  
Powder Metallurgy Route

Diffusion-controlled formation mechanism of dual-phase structure during Al induced crystallization of SiGe

2012 ◽  
Vol 100 (7) ◽  
pp. 071908 ◽  
Author(s):  
Tian-Wei Zhang ◽  
Fei Ma ◽  
Wei-Lin Zhang ◽  
Da-Yan Ma ◽  
Ke-Wei Xu ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Phase Structure ◽  
Dual Phase ◽  
Diffusion Controlled ◽  
Induced Crystallization

scholarly journals Formation Mechanism of Nano-Strengthening Particles in Dispersion Strengthened W-Ti Alloys

2020 ◽  
Vol 15 (0) ◽  
pp. 1205021-1205021 ◽  
Author(s):  
Hiroyuki NOTO ◽  
Yoshimitsu HISHINUMA ◽  
Takeo MUROGA ◽  
Hideo BENOKI
Keyword(s):  
Formation Mechanism ◽  
Ti Alloys ◽  
Strengthening Particles

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

Direct Observation of the Diffusionless β → β + ω Transformation in Titanium Alloys

1971 ◽  
Vol 29 ◽  
pp. 122-123
Author(s):  
N. E. Paton ◽  
D. de Fontaine ◽  
J. C. Williams
Keyword(s):  
Electron Microscope ◽  
Titanium Alloys ◽  
Direct Observation ◽  
Dark Field ◽  
X Ray Diffraction ◽  
Resistivity Measurements ◽  
Selected Area Electron Diffraction ◽  
Ti Alloys ◽  
Thin Foils ◽  
Field Device

The electron microscope has been used to study the diffusionless β → β + ω transformation occurring in certain titanium alloys at low temperatures. Evidence for such a transformation was obtained by Cometto et al by means of x-ray diffraction and resistivity measurements on a Ti-Nb alloy. The present work shows that this type of transformation can occur in several Ti alloys of suitable composition, and some of the details of the transformation are elucidated by means of direct observation in the electron microscope.Thin foils were examined in a Philips EM-300 electron microscope equipped with a uniaxial tilt, liquid nitrogen cooled, cold stage and a high resolution dark field device. Selected area electron diffraction was used to identify the phases present and the ω-phase was imaged in dark field by using a (101)ω reflection. Alloys were water quenched from 950°C, thinned, and mounted between copper grids to minimize temperature gradients in the foil.

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