Microstructural factors in the primary creep stage of two-phase titanium alloy

• Autorzy: Ziaja W. , Motyka M. , Sieniawski J.

Identyfikatory

DOI

10.15199/28.2016.4.8

Warianty tytułu

PL

Oddziaływanie mikrostruktury na proces pełzania nieustalonego dwufazowego stopu tytanu

• Języki publikacji: EN

Abstrakty

EN

One of the major areas of titanium alloys application includes discs and blades of compressors in turbine engines. In titanium alloys, significant strain can accumulate as a function of time, at stresses well below the yield strength at the homologous temperature below 0.25, even at room temperature. Life prediction for elements made of titanium alloys which is based solely on steady state creep parameters is in some cases not adequate due to large primary creep strains. In the case of rotating components of aero-engines small dimensional tolerances can be threatened and transient creep strains must be taken into account in modelling of overall creep deformation. Creep and fatigue properties of two-phase titanium alloys show strong dependence on microstructure, especially morphology of the α and β phases which can be controlled to certain extent by proper selection of hot working and heat treatment conditions. In the paper the primary creep behaviour of Ti–6Al–2Mo–2Cr alloy (VT3–1) at elevated temperature was investigated. The microstructure of the alloy was varied by means of changing conditions of heat-treatment. Creep tests were carried out on the alloy with globular and lamellar microstructure at the temperature of 450°C. Primary stage of the creep process was described using various constitutive laws. Applicability of power-law and logarithmic equations for describing strain evolution was verified. The influence of the initial microstructure on the primary creep strain and strain rate at the onset of steady-state creep stage was analysed.

PL

W pracy podjęto próbę określenia oddziaływania morfologii mikrostruktury dwufazowego stopu tytanu Ti–6Al–2Mo–2Cr na jego właściwości w stadium pełzania nieustalonego w temperaturze 450°C. Istotnym celem badań był dobór równań konstytutywnych opisujących krzywe pełzania stopu, które mogą być zastosowane do ilościowej oceny wpływu morfologii mikrostruktury stopu na wielkości charakteryzujące proces pełzania. Zagadnienie to jest istotne w procesie projektowania elementów konstrukcyjnych, zwłaszcza w przypadku małych tolerancji wymiarów (np. łopatki wirnika sprężarki silnika turbinowego), ze względu na skłonność stopów tytanu do osiągania znacznych odkształceń trwałych, zależnych od czasu, nawet w zakresie temperatury homologicznej poniżej 0,25.

Słowa kluczowe

EN

two-phase titanium alloys; primary creep; microstructure

PL

stop tytanu dwufazowy; pełzanie nieustalone; mikrostruktura

• Wydawca: Wydawnictwo SIGMA-NOT
• Czasopismo: Inżynieria Materiałowa
• Rocznik: 2016
• Tom: Vol. 37, nr 4
• Strony: 196--200
• Opis fizyczny: Bibliogr. 16 poz., fig., tab.

Twórcy

autor

Ziaja W.

• Department of Material Science, Rzeszów University of Technology, Rzeszów, Poland

autor

Motyka M.

• Department of Material Science, Rzeszów University of Technology, Rzeszów, Poland

autor

Sieniawski J.

• Department of Material Science, Rzeszów University of Technology, Rzeszów, Poland

Bibliografia

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• [7] Motyka M., Ziaja W., Kubiak K., Sieniawski J.: Influence of thermomechanical processing conditions on microstructure and hot plasticity of Ti- 6Al-4V alloy. Inżynieria Materiałowa Materials Engineering 30 (5) (2009) 322÷325.
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• [14] Gollapudi S., Satyanarayana D. V. V., Phaniraj C., Nandy T. K.: Transient creep in titanium alloys: Effect of stress, temperature and trace element concentration. Mater. Sci. Eng. A 556 (2012) 510÷518.
• [15] Balasundar I., Raghu T., Kashyap B. P.: Correlation between microstructural features and creep strain in a near-α titanium alloy processed in the α + β regime. Mater. Sci. Eng. A 609 (2014) 241÷249.
• [16] Barboza M. J. R., Moura Neto C., Silva C. R. M.: Creep mechanisms and physical modelling for Ti–6Al–4V. Mater. Sci. Eng. A 369 (2004) 201÷209.

Uwagi

Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę.