Lamellae growth in fully lamellar TiAl alloys and its factors

It is important to control the lamellar spacing of fully la mellar TiAl alloy for improving its mechanical properties. The factors affecting the lamellar spacing of fully lamellar TiAl alloy and the dependence of the lam ellar spacing on the factors were investigated by means of OM and TEM. The resul ts show that the lamellar spacing depends on cooling rate and Al content. The la mellar spacing is inversely proportional to cooling rate and increases with the increase of Al content. At the same time, a theoretical expression of the lamell ar spacing of fully lamellar TiAl alloy during continuous cooling has been deriv ed on the basis of the ledge mechanism of lamellae growth. The theoretical resul ts are in agreement with the experimental findings.