Ordinary dislocation configurations in high Nb-containing TiAl alloy deformed at high temperatures

Lin Song, Junpin Lin, Jinshan Li

科研成果: 期刊稿件文章同行评审

7 引用 (Scopus)

摘要

High Nb-containing TiAl (Nb–TiAl) alloys possess mechanical properties at elevated temperatures superior to conventional TiAl alloys. However, the strengthening mechanisms induced by Nb addition have been discussed controversial for a long time. In the present study, the dislocation structures in a polycrystalline high Nb–TiAl alloy after tensile tests at 700 and 900 °C were investigated by transmission electron microscope (TEM) observation. The results show that abundant double cross slip of ordinary dislocations is activated in the samples deformed at 700 °C. The dislocations are pinned at the jogs and numerous dipoles are observed. Debris can be commonly observed in the vicinity of screw dislocations. Trace analysis shows that the cross-slip plane is (1 1 0)γ at 700 °C but (1 1 1)γ octahedral plane at 900 °C. Three-dimensional (3D) dislocation structures, caused by cross-slip and annihilation of ordinary dislocations, were observed along the screw orientation. The dipoles and debris produced by high-temperature cross slip can be important for the strengthening of high Nb–TiAl alloys.

源语言英语
页(从-至)515-526
页数12
期刊Philosophical Magazine
97
7
DOI
出版状态已出版 - 3 3月 2017

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