Discontinuous coarsening of primary alpha(2)/gamma lamellae at colony boundaries in gamma-TiAl-based alloys

作者：Qin GW^*; Wang JJ; Hao SM

来源：Intermetallics, 1999, 7(1): 1-4.

DOI：10.1016/S0966-9795(98)00003-X

• based on TiAl
• phase stability
• grain boundaries
• phase transformation

The discontinuous coarsening of primary alpha(2)/gamma lamellae at lamellar colony boundaries was studied by TEM and optical microscopy for the Ti-40Al, Ti-42Al and Ti-45Al (in at%) alloys which were isothermally aged at 1000 degrees C for various time after being solution-treated in the a single-phase field, and then water quenched to room temperature. Discontinuous coarsening nuclei form at lamellar colony boundaries and grow into the neighboring colony. With increasing Al concentrations in the alloys, the degree of the discontinuous coarsening becomes greater. The size of discontinuous coarsening cells increases linearly with time in the first hour for the Ti-42Al alloy and the growth velocity is about 1.17x10(-8)ms(-1). However, at larger times, the microstructure stabilizes and further discontinuous coarsening occurs at much slower rates.

• 出版日期1999-1
• 单位东北大学