Evolution of solid-liquid interface
morphology of primary TiB2 in non-
equilibrium solidified Ti-Al-B alloys
morphology of primary TiB2 in non-
equilibrium solidified Ti-Al-B alloys
(1. School of Materials Science and Engineering,
Beijing University of Aeronautics and Astronautics, Beijing 100083, China;
2. School of Materials Science and Engineering,
Harbin Institute of Technology, Harbin 150001, China)
Beijing University of Aeronautics and Astronautics, Beijing 100083, China;
2. School of Materials Science and Engineering,
Harbin Institute of Technology, Harbin 150001, China)
Abstract: Ti-Al-B alloys were produced by in-situ synthesis method. The phase constitut ions, microstructure of these alloys and the morphology of the primary TiB2 we re investigated by XRD and SEM. The results show that these alloys are composed of TiAl and TiB2, and the primary TiB2 is hexagonal prism shape. Growth terraces, pyramidal protrusion, and rod shape dendrites are observed on (0001) plane of primary TiB2. There are thin flake convexes on plane of primary TiB2, parallel to (0001) plane of the primary TiB2. The rod-shaped crystal orientation and thin flake convexes are parallel to primary TiB2 where they protrude out. The solid-liquid interface morphology of primary TiB2 during solidification was also investigated. It was indicated that the solid-liquid interface morphology of primary TiB2 is instable and gradually develops into a complicated interface consisted of a few separated secondary interfaces. These secondary interfaces are facet with the same crystalline orientation.
Key words: TiAl; TiB2; titanium alloys; crystal growth