TY - JOUR

T1 - Precipitation behavior of hexagonal carbides in a C containing intermetallic γ-TiAl based alloy

AU - Burtscher, Michael

AU - Weißensteiner, Irmgard

AU - Wartbichler, Reinhold

AU - Kirchheimer, Katharina

AU - Bernhard, Christian

AU - Kiener, Daniel

AU - Clemens, Helmut

PY - 2023/10/4

Y1 - 2023/10/4

N2 - Intermetallic γ-TiAl based alloys are currently used as structural materials in high-temperature applications such as turbocharger wheels, valves and turbine blades. Adding C yields solid solution and precipitation hardening of the TiAl alloys, which raises their service temperature. Within this work, the effect of C on the TNM alloying system is analyzed by complementary differential scanning calorimetry measurements and selected heat treatments in conjunction with detailed electron microscopy analysis. This allowed the determination of the transition temperatures and revealed the precipitation onset of hexagonal Ti2AlC carbides between 1450 °C and 1475 °C. The precipitation kinetics of the carbides were further investigated by laser scanning confocal microscopy and revealed a preferred and steady growth in the length direction. Further, orientation relationships between the TiAl phases and the carbides from Blackburn and Burgers type could be determined by electron back-scatter diffraction. The results of this study provide a better understanding of the effect of C addition on the TNM alloy and thus enable further improvement of the alloying design process.

AB - Intermetallic γ-TiAl based alloys are currently used as structural materials in high-temperature applications such as turbocharger wheels, valves and turbine blades. Adding C yields solid solution and precipitation hardening of the TiAl alloys, which raises their service temperature. Within this work, the effect of C on the TNM alloying system is analyzed by complementary differential scanning calorimetry measurements and selected heat treatments in conjunction with detailed electron microscopy analysis. This allowed the determination of the transition temperatures and revealed the precipitation onset of hexagonal Ti2AlC carbides between 1450 °C and 1475 °C. The precipitation kinetics of the carbides were further investigated by laser scanning confocal microscopy and revealed a preferred and steady growth in the length direction. Further, orientation relationships between the TiAl phases and the carbides from Blackburn and Burgers type could be determined by electron back-scatter diffraction. The results of this study provide a better understanding of the effect of C addition on the TNM alloy and thus enable further improvement of the alloying design process.

U2 - 10.1016/j.jallcom.2023.172400

DO - 10.1016/j.jallcom.2023.172400

M3 - Article

VL - 2023

JO - Journal of alloys and compounds

JF - Journal of alloys and compounds

SN - 0925-8388

IS - 969

M1 - 172400

ER -