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Original title:
THE EFFECT OF MO AND/OR C ADDITION ON MICROSTRUCTURE AND PROPERTIES OF TIAL ALLOYS
Authors: Chlupová, Alice ; Kruml, Tomáš ; Roupcová, Pavla ; Heczko, Milan ; Obrtlík, Karel ; Beran, Přemysl
Document type: Papers
Conference/Event: METAL 2015 - International Conference on Metallurgy and Materials /24./, Brno (CZ), 2015-06-03 / 2015-06-05
Year: 2015
Language: eng
Abstract: Cast TiAl alloys with high Nb content are subject of extensive research with the aim to develop material with low density, good corrosion resistance and high strength at elevated temperatures. Disadvantage of their broad applications is restricted workability, machinability and low fracture toughness especially at room temperature. Improvement of properties of TiAl based materials can be achieved by tailoring the microstructure by modification of chemical composition. For this purpose 5 types of TiAl alloys with 7 % of Nb were prepared having variable content of Mo and/or C. Addition of Mo and/or C resulted in three types of microstructure and different phase composition. All modified alloys contain colonies consisting of thin lamellae of a and g phases sometimes complemented by g and/or b phase at the grain boundaries. Variable microstructure and phase composition resulted in differences in mechanical behaviour. The most promising tensile properties at both room and elevated temperature were observed for alloy doped with 2 % of Mo having the mixed microstructure containing b phase and for alloy doped with 0.5 % of C with nearly lamellar microstructure without b phase. 2Mo alloy exhibited reasonably good ductility while 0.5C alloy reached the highest tensile strength. Also low cycle fatigue behaviour of these two materials was the best of all five materials under investigation. Fatigue deformation characteristics were better in the case of 2Mo alloy while 0.5C alloy exhibited higher cyclic stresses. Fracture mechanisms were determined using fractographic analysis. The major fracture mode of all alloys was trans-lamellar.
Keywords: effect of alloying; fractography; mechanical properties; microstructure; TiAl
Project no.: GAP107/11/0704 (CEP), GA15-08826S (CEP), ED1.1.00/02.0068
Funding provider: GA ČR, GA ČR, GA MŠk
Host item entry: Metal 2015: 24th International Conference on Metallurgy and Materials, ISBN 978-80-87294-58-1
Institution: Institute of Physics of Materials AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0251584
Permalink: http://www.nusl.cz/ntk/nusl-200947
The record appears in these collections:
Research > Institutes ASCR > Institute of Physics of Materials
Conference materials > Papers
Authors: Chlupová, Alice ; Kruml, Tomáš ; Roupcová, Pavla ; Heczko, Milan ; Obrtlík, Karel ; Beran, Přemysl
Document type: Papers
Conference/Event: METAL 2015 - International Conference on Metallurgy and Materials /24./, Brno (CZ), 2015-06-03 / 2015-06-05
Year: 2015
Language: eng
Abstract: Cast TiAl alloys with high Nb content are subject of extensive research with the aim to develop material with low density, good corrosion resistance and high strength at elevated temperatures. Disadvantage of their broad applications is restricted workability, machinability and low fracture toughness especially at room temperature. Improvement of properties of TiAl based materials can be achieved by tailoring the microstructure by modification of chemical composition. For this purpose 5 types of TiAl alloys with 7 % of Nb were prepared having variable content of Mo and/or C. Addition of Mo and/or C resulted in three types of microstructure and different phase composition. All modified alloys contain colonies consisting of thin lamellae of a and g phases sometimes complemented by g and/or b phase at the grain boundaries. Variable microstructure and phase composition resulted in differences in mechanical behaviour. The most promising tensile properties at both room and elevated temperature were observed for alloy doped with 2 % of Mo having the mixed microstructure containing b phase and for alloy doped with 0.5 % of C with nearly lamellar microstructure without b phase. 2Mo alloy exhibited reasonably good ductility while 0.5C alloy reached the highest tensile strength. Also low cycle fatigue behaviour of these two materials was the best of all five materials under investigation. Fatigue deformation characteristics were better in the case of 2Mo alloy while 0.5C alloy exhibited higher cyclic stresses. Fracture mechanisms were determined using fractographic analysis. The major fracture mode of all alloys was trans-lamellar.
Keywords: effect of alloying; fractography; mechanical properties; microstructure; TiAl
Project no.: GAP107/11/0704 (CEP), GA15-08826S (CEP), ED1.1.00/02.0068
Funding provider: GA ČR, GA ČR, GA MŠk
Host item entry: Metal 2015: 24th International Conference on Metallurgy and Materials, ISBN 978-80-87294-58-1
Institution: Institute of Physics of Materials AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0251584
Permalink: http://www.nusl.cz/ntk/nusl-200947
The record appears in these collections:
Research > Institutes ASCR > Institute of Physics of Materials
Conference materials > Papers
Record created 2015-11-14, last modified 2022-09-29