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In situ Observation of the Initial Stage of γ Lamella Formation in Ti48Al2Cr2Nb Alloy
Author(s) -
Li Xiaolei,
Li Jinshan,
Kou Hongchao,
Song Lin
Publication year - 2017
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201600670
Subject(s) - lamella (surface anatomy) , lamellar structure , materials science , nucleation , alloy , in situ , electron backscatter diffraction , grain boundary , crystallography , composite material , microstructure , thermodynamics , chemistry , organic chemistry , physics
In situ observation is carried out in Ti48Al2Cr2Nb (at%) alloy to obtain a comprehensive understanding on the growth mechanisms of γ lamellae. The results reveal that the grain‐boundary nucleated γ embryos occur first and grow into the adjacent α grains. Both the γ lamellae nucleated at the grain boundary and within α grain prefer to grow in pair by nucleation of the new γ lamella adjacent to the precedent γ lamella or branching of the growth tip. The widening of γ lamellae is controlled by the migration of α/γ interface, and the distance between growth pairs directly influences the lamellar width. The EBSD results exhibit that the two γ lamellae in growth pairs have a true‐twin or pseudo‐twin relationship. The underlying growth mechanism of γ lamellae is discussed.