Microstructure Evolution of Ti-5Al-5V-5Mo-3Cr after Hot Deformation at Large and Moderate Strains

Cecilia Poletti; Ricardo H. Buzolin; Sanjev Kumar; Peng Wang; Thierry Franz Jules Simonet-Fotso

doi:10.4028/www.scientific.net/MSF.941.1443

Paper Titles

Microstructure and Texture of MX20 after Conventional Rolling and Rolling from Twin Rolled Cast Strip
p.1418

Simulation of Thermal Phenomena in Reverse Strip-Rolling Process
p.1424

Magnesium Twin-Roll Casting Technology for Flat and Long Products - State of the Art and Future
p.1431

Microstructure Characterization of AlSi10Mg Fabricated by Selective Laser Melting Process
p.1437

Microstructure Evolution of Ti-5Al-5V-5Mo-3Cr after Hot Deformation at Large and Moderate Strains
p.1443

Material Flow in Lap Joint of Dissimilar Metallic Foils by Friction Stir Diffusion Bonding with Micro Indentation
p.1450

Analytical Design of Superelastic Ring Springs for High Energy Dissipation
p.1457

An In Situ Observation of Slip Deformation in a Compressed Ti-Mo-Al Single Crystal
p.1463

Simultaneous Prediction of Bendability and Deep Drawability Based on Orientation Distribution Function for Polycrystalline Cubic Metal Sheets
p.1468

HomeMaterials Science ForumMaterials Science Forum Vol. 941Microstructure Evolution of Ti-5Al-5V-5Mo-3Cr...

Microstructure Evolution of Ti-5Al-5V-5Mo-3Cr after Hot Deformation at Large and Moderate Strains

Abstract:

This work deals with the analysis and modelling of the microstructural evolution of the metastable titanium alloy Ti-5Al-5V-5Mo-3Cr during hot deformation up to moderate and large strains. Experimental flow curves and deformed samples are obtained by hot compression and hot torsion tests using a Gleeble ® 3800 device. The samples are deformed above and below the beta transus temperature and in a wide range of strain rates. Microstructures are characterized after deformation and in-situ water quenching using light optical and scanning electron microscopy and electron back scattered diffraction (EBSD). Dynamic recovery of the beta phase is found to be the main deformation mechanism up to moderated strains. By increasing the strain, continuous dynamic recrystallization (cDRX) is confirmed by the progressive conversion of low angle boundaries into high-angle boundaries. Alpha phase plays a secondary role in the deformation of the material by pinning the movement of beta high angle grain boundaries (HAGB). The evolution of the microstructure is modelled using dislocation density as internal variable in the single β field.

You might also be interested in these eBooks

View Preview

Info:

Periodical:

Materials Science Forum (Volume 941)

Pages:

1443-1449

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.941.1443

Citation:

Cite this paper

Online since:

December 2018

Authors:

Cecilia Poletti*, Ricardo H. Buzolin, Sanjev Kumar, Peng Wang, Thierry Franz Jules Simonet-Fotso

Keywords:

Dynamic Recovery, Hot Deformation, Large Plastic Deformation, Ti5553

Export:

RIS, BibTeX

Price:

Permissions:

Request Permissions

* - Corresponding Author

References

[1] 33E+07 700.

07.

27 230 110.

[1] 4 47721-20.15 T.

[3] 16E-10 The yield stress was difficult to determine due to a discontinuous yielding occurring at almost all temperatures but could be fitted linearly with respect to the log (strain rate). Fig.7 shows a good correlation between the measured experimental data and the modelled flow stresses. Only the discontinuous yielding could not be catch well at any deformation condition. The softening at high strain rates must be related to the lack of recovery and the fast formation of locally new recrystallized grains. The model must be optimized to describe the dislocation cumulation at HAGB and the local generation of new recrystallized grains. Figure 7 Measured (full line) and modelled (dashed line) flow stresses in the single b field. Fig.8 shows the calculated increment in the dislocation density for different deformation conditions: slower strain rates and higher temperatures are related to lower dislocation density. One of the characteristics of this model is that the dislocation density saturates with the strain. This steady-state is achieved at lower strains if the strain rate is low due to favourable conditions for recovery. Figure 8 Modelled dislocation density evolution at different strain rates and temperatures. Summary and Conclusions The hot deformation behaviour of Ti5553 was studied by experimental and modelling approaches. The following could be concluded: - Dynamic recovery occurs heterogeneously for all the samples - The grain size of the grain formed by cDRX is the same as of the subgrain in all the cases. - The cumulation of dislocations at grain boundaries produces local recovery and local cDRX. - Deformations at high strain rates are characterized by the formation of many bands of dislocations starting at HAGB. After saturation of dislocations, new bands are formed. - Flow softening in α+b field occurs due to the fragmentation of α and the increment in the size of b subgrains - A simple model was successfully developed but could not catch the softening due to cDRX Acknowledgments The authors carried out this work under the following projects: FWF Project P 29727, CD-Laboratory for Design of High-Performance Alloys by Thermomechanical Processing, and FWF Project P 2747. References.

Google Scholar