The Influence of Nb, Zr, and Zr + Hf on the Lattice Parameters and Creep Behavior of β-Solidifying γ-TiAl Alloys

Imayev, V. M.; Parkhimovich, Nikolay; Trofimov, Denis; Imayev, R. M.

doi:10.1007/s11665-022-06673-z

Cited by 5 publications

(1 citation statement)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[1] For RB and PT, a lattice mismatch exists at the interface which leads to condition of coherency stresses or misfit dislocations. [7,8,[14][15][16][17][18] The role of these rotational interfaces on slip transmission has been studied before, [10,[19][20][21][22][23][24] but the role of each isolated interface on the deformation behavior is not clear.…”

Section: Introductionmentioning

confidence: 99%

How Coherent and Semi‐Coherent Interfaces Govern Dislocation Nucleation in Lamellar TiAl Alloys

Chauniyal

Janisch

2023

Adv Eng Mater

View full text Add to dashboard Cite

γ/γ interfaces drive plastic deformation in lamellar TiAl alloys. Due to the ordering and resulting tetragonal nature of γ phase, γ/γ twin interfaces exist as different variants, some of which exhibit coherency stresses or semicoherent interface structures. While geometric parameters, such as the lamella spacing and orientation, are explored extensively in experiments, the isolation of individual influence of different interfaces in a nanolamellar microstructure remains a challenge. Herein, the range of γ/γ interface states is modeled using bilayers of the coherent γ/γTrueTwin, and the coherent or semicoherent γ/γPseudoTwin, and their deformation behavior is compared. It is shown that residual coherency stresses arise due to misfit accommodation in coherent γ/γPT specimens, which causes early preferential nucleation in one γ layer. Similarly, semicoherent specimens show preferential nucleation from misfit dislocations at the interface, which obeys Schmid's rule. In contrast, coherent γ/γTT specimens show no preferential nucleation and therefore exhibit higher strength. Thus, it is demonstrated that the presence of rotational γ/γ interfaces with misfit is responsible for localized and early plasticity, that lowers the strength of a lamellar microstructure. The interface type, which considers the coherency state, is used as a criterion for alloy microstructure design in the future.

show abstract