The thermal stability of the as-cast lamellar structure of the Ti-48Al, Ti
45Al-3Ga, Ti-45Al-2Nb-2Cr, Ti-46Al and Ti-46Al-1.0Si alloys tin at.%) at 11
50 and 1000 degreesC was studied by optical microscopy. The addition of 1.0
Si has been demonstrated to have a remarkable improvement on the thermal st
ability of the lamellar structure of TiAl alloy at high temperatures, but t
he precise mechanism for this improvement needs to be clarified. (C) 2001 E
lsevier Science Ltd. All rights reserved.