STRUCTURE AND FORMATION MECHANISM OF DISLOCATION NETWORKS IN TiAl+
来源期刊：中南大学学报(英文版)1995年第1期
论文作者：Qu Xuanhui Huang Baiyun
文章页码：12 - 15
Key words：ordered alloy; intermetallic compound; dislocation networks; TEM; ductility/TiAl;titanium aluminide
Abstract: The structure and characteristics of dislocation networks in Ti50 Al ordered alloy deformed at room temperature were studied by means of TEM diffraction contrast analysis technique. The results show that the observed dislocation networks consist of three types of dislocations with the Burgers vectors of 1/2 and 1/2 respectively. It is proposed that these networks are produced from the intersection of a group of ordinary dislocations on (111) plane with the superdislocations moving on the coupling plane,and at the intersection points dislocation nodes with are formed by dislocation reaction. In the networks, most of the dislocation segments are lying in the directions corresponding to their deep Peierls valleys due to the directional Ti-Ti covalent bonds and tend to be sessile, which is believed to be one of the factors responsible for the low-temperature brittleness of TiAl. In addition, the effects of alloying on the dislocation networks and ductility of TiAl alloy are also discussed.
Qu Xuanhui; Huang Baiyun
(Powder Metallurgy Research Institute, Central South University of Technology, Changsha, 410083, China)
Abstract:The structure and characteristics of dislocation networks in Ti50 Al ordered alloy deformed at room temperature were studied by means of TEM diffraction contrast analysis technique. The results show that the observed dislocation networks consist of three types of dislocations with the Burgers vectors of 1/2 and 1/2 respectively. It is proposed that these networks are produced from the intersection of a group of ordinary dislocations on (111) plane with the superdislocations moving on the coupling plane,and at the intersection points dislocation nodes with are formed by dislocation reaction. In the networks, most of the dislocation segments are lying in the directions corresponding to their deep Peierls valleys due to the directional Ti-Ti covalent bonds and tend to be sessile, which is believed to be one of the factors responsible for the low-temperature brittleness of TiAl. In addition, the effects of alloying on the dislocation networks and ductility of TiAl alloy are also discussed.
Key words:ordered alloy; intermetallic compound; dislocation networks; TEM; ductility/TiAl;titanium aluminide
