Microstructural Characteristics of Ti-48Al-2Cr Alloy

摘要

The microstructural characteristics of two-phase #alpha#_2 + #gamma# titanium aluminide before and after deformation are investigated by transmission electron microscopy (TEM). The orientation relationships associated with the #gamma#-#gamma# combinations can be divided into three types: true twin, order domain, and pseudo-twin. Of the three orientation relationships, true twin accounts for more than 50 percent, which is most likely due to a minimization of interfacial energy related to misfit and interaction energy of interface atoms. During deformation, lamellar boundaries cause different resistance to the propagation of intersecting twin. Experimental observations and theoretical analysis consistently show that the resistance has the following sequence: F_(120 deg)< F_(180 deg)< F_(60 deg)< F_(#alpha#2/#gamma#).