Influence of microstructure on the mechanical properties of heat-treated cast lamellar structure
- Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Materials Science and Engineering
The lamellar structure of ({alpha} + {gamma}) two-phase Ti-Al alloys is known as a promising structure because of its good fracture toughness and creep properties, despite its comparatively low ductility at ambient temperature. The purpose of the present work was to investigate the effect of lamellar structure on the mechanical properties of cast lamellar structure by controlling, as precisely as possible, its lamellar grain size, lamellar spacing, and ordered domain sizes. The volume fraction effect of {alpha}{sub 2} phase has been also investigated. It is normally difficult to obtain a small sized grain (i.e., {approximately}300 {micro}m) in a cast lamellar structure since the grain size of as-cast structure is already large (i.e., {approximately}600 {micro}m). To circumvent this difficulty, the authors have fully coarsened the cast lamellar structure by discontinuous coarsening before solutionizing it in an {alpha} single phase field. This has produced a starting grain size of 10--130 {micro}m, lamellae of which are fully coarsened. The tensile yield stress has been measured using a miniaturized disk bend test (MDBT) used by Ardell and his coworkers. This method has, in particular, an advantage to monitor the yield stress of alloys using a small amount of specimen and to control precisely the grain and lamellar sizes of testing specimens because of its small dimension.
- OSTI ID:
- 247978
- Journal Information:
- Scripta Materialia, Vol. 34, Issue 10; Other Information: PBD: 15 May 1996
- Country of Publication:
- United States
- Language:
- English
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