Microstructure and mechanical properties of ultra-fine grained titanium alloys

• Název práce v češtině: Mikrostruktura a mechanické vlastnosti ultrajemnozrnných slitin titanu
• Název v anglickém jazyce: Microstructure and mechanical properties of ultra-fine grained titanium alloys
• Klíčová slova: titanium alloys, ultra-fine grained microstructure, dislocation density, microhardness
• Klíčová slova anglicky: titanium alloys, ultra-fine grained microstructure, dislocation density, microhardness
• Akademický rok vypsání: 2013/2014
• Typ práce: diplomová práce
• Jazyk práce: angličtina
• Ústav: Katedra fyziky materiálů (32-KFM)
• Vedoucí / školitel: doc. PhDr. RNDr. Josef Stráský, Ph.D.
• Řešitel: skrytý - zadáno a potvrzeno stud. odd.
• Datum přihlášení: 18.02.2014
• Datum zadání: 26.06.2014
• Datum potvrzení stud. oddělením: 10.02.2015
• Datum a čas obhajoby: 10.06.2015 00:00
• Datum odevzdání elektronické podoby: 07.05.2015
• Datum odevzdání tištěné podoby: 15.05.2015
• Datum proběhlé obhajoby: 10.06.2015
• Oponenti: prof. RNDr. Vladimír Šíma, CSc.

Zásady pro vypracování

1) Student will compose literature review covering ultra-fine grained materials, biomedical titanium alloys and metastable beta titanium alloys.
2) Student will measure microhardness of different alloys after high-pressure torsion.
3) Student will observe microstructure of studied materials using light microscopy and electron microscopy.
4) Student will participate on dislocation density measurements.
5) Student will use in-situ experimental techniques to determine thermally activated processes in studied materials.
6) Microhardness measurements and microstructure observation will be correlated with parameters of severe-plastic deformation processes.
7) Recovery, recrystallization and phase transformation processes will be identified and correlated to thermal treatment.
8) Achieved results will be summarized in diploma thesis.

Seznam odborné literatury

G. Lutjering, J.C. Williams; Titanium; Springer; 2007
A.P. Zhilayev, T.G. Langdon; Using high-pressure torsion for metal processing: Fundamentals and applications; Prog Mat Sci 53; 2008
O. Srba; Komplexní studium jemnozrnných polykrystalů Cu a slitiny CuZr připravených metodami equal channel angular pressing a high pressure torsion; disertační práce; 2011
R. Z. Valiev, I.P. Semenova, E. Jakushina, V.V. Latysh, H. Rack, T.C. Lowe, J. Petruželka, L. Dluhoš, D. Hrušák, J. Sochová; Nanostructured SPD Processed Titanium for Medical Implants, Mat Sci Forum Vols. 584-586; 2008
M. Janeček, J. Stráský, J Čížek, P. Harcuba, K. Václavová, V.V. Polyakova, I.P. Semenova; Mechanical properties and dislocation structure evolution in Ti6Al7Nb alloy processed by high pressure torsion, Met Mat Trans, April 2013
L.F. Zeipper, M.J. Zehetbauer, Ch. Hozleitner; Defect based micromechincal modelling and simulation of nanoSPD CP-Ti in post-deformation; Mat Sci Eng A 410-411, 2008
J. Čížek, M. Janeček, O. Srba, R. Kužel, Z. Barnovská, I. Procházka, S. Dobatkin; Evolution of defects in copper deformed by high-pressure torsion, Acta Mat 59, 2011

Předběžná náplň práce

The advantages of ultra-fine grained microstructure on mechanical properties have been studied for last two decades. However, production of ultra-fine grained (UFG) titanium and especially UFG titanium alloys has been made possible only in last few years. Experimental data describing properties of these materials are scarce and relations between material preparation, microstructure and mechanical properties are unrevealed. Simultaneously, there is increased interest in metastable beta titanium alloys that provide unique properties thanks to extreme hardening capabilities via series of phase transformations. The effect of ultra-fine grained microstructure on these phase transformations is unknown.
The diploma thesis aims on experimental characterization of UFG titanium alloys employing wide spectrum of experimental techniques. Furthermore, microstructure and defect structure evolution at elevated temperatures will be studied by in-situ and ex-situ methods.