TY - JOUR

T1 - On the stability of Ti(Mn,Al)2 C14 Laves phase in an intermetallic Ti–42Al–5Mn alloy

AU - Graf, Gloria

AU - Seyffertitz, Malina

AU - Spörk-Erdely, Petra

AU - Clemens, Helmut

AU - Stark, Andreas

AU - Hatzenbichler, Lukas

AU - Holec, David

AU - Burtscher, Michael

AU - Kiener, Daniel

AU - Li, Xiaobing

AU - Liu, Kui

N1 - Publisher Copyright: © 2023 The Authors

PY - 2023/6/11

Y1 - 2023/6/11

N2 - In order to facilitate a more widespread use of intermetallic γ-TiAl based alloys in the aircraft and automotive sector, recent research focuses on the development of low-cost titanium aluminides. The strong β-stabilizing effect as well as the increased ductility upon Mn addition renders this alloying element a promising candidate to fully or partially substitute other, more expensive, alloying elements such as Mo, Ta and Nb. Mn-containing γ-TiAl based alloys, however, are prone to the formation of the undesired, brittle Ti(Mn,Al) 2 C14 Laves phase during long-term exposure at the targeted service temperatures, which can deteriorate the ductility at ambient temperatures. In this study, the transformation kinetics as well as the chemical and thermal existence range of the C14 Laves phase in the low-cost Ti–42Al–5Mn (at.%) alloy were investigated by complementary experimental and computational approaches. In situ and ex situ high-energy X-ray diffraction in combination with microstructural investigations were used to study the occurrence and transformation kinetics of possible Laves phase formation in the course of annealing treatments. The chemical stability range of the C14 Laves phase was addressed by chemical analysis in conjunction with complementary ab initio modeling. Using these combined approaches, the critical local Mn concentration of ∼16 at.% for Laves phase formation within lamellar α 2 and ∼17 at.% within β o in the Ti–42Al–5Mn alloy was determined. These results should be critically considered for future design of advanced low-cost γ-TiAl based alloys.

AB - In order to facilitate a more widespread use of intermetallic γ-TiAl based alloys in the aircraft and automotive sector, recent research focuses on the development of low-cost titanium aluminides. The strong β-stabilizing effect as well as the increased ductility upon Mn addition renders this alloying element a promising candidate to fully or partially substitute other, more expensive, alloying elements such as Mo, Ta and Nb. Mn-containing γ-TiAl based alloys, however, are prone to the formation of the undesired, brittle Ti(Mn,Al) 2 C14 Laves phase during long-term exposure at the targeted service temperatures, which can deteriorate the ductility at ambient temperatures. In this study, the transformation kinetics as well as the chemical and thermal existence range of the C14 Laves phase in the low-cost Ti–42Al–5Mn (at.%) alloy were investigated by complementary experimental and computational approaches. In situ and ex situ high-energy X-ray diffraction in combination with microstructural investigations were used to study the occurrence and transformation kinetics of possible Laves phase formation in the course of annealing treatments. The chemical stability range of the C14 Laves phase was addressed by chemical analysis in conjunction with complementary ab initio modeling. Using these combined approaches, the critical local Mn concentration of ∼16 at.% for Laves phase formation within lamellar α 2 and ∼17 at.% within β o in the Ti–42Al–5Mn alloy was determined. These results should be critically considered for future design of advanced low-cost γ-TiAl based alloys.

UR - http://www.scopus.com/inward/record.url?scp=85161636605&partnerID=8YFLogxK

U2 - 10.1016/j.intermet.2023.107962

DO - 10.1016/j.intermet.2023.107962

M3 - Article

VL - 2023

JO - Intermetallics

JF - Intermetallics

SN - 0966-9795

IS - 161

M1 - 107962

ER -