EBSD investigation on the interface microstructure evolution of Ti-Al3Ti laminated composites during the preparation process

Abstract

In present work, two Ti-Al3Ti laminated composites containing different fractions of Al were fabricated by vacuum hot pressing sintering with the same process but different reaction time at 660 °C. Electron back scattering diffraction (EBSD) technology was used to characterize the microstructure evolution of Al3Ti layer at Ti/Al3Ti interface and Al3Ti/Al interface of the two specimens respectively, including the mean grain size, the distribution of grain boundaries, the crystallographic orientation distribution and the dislocation density. The results showed that: for the mean grain size of Al3Ti, a decreased tendency was occurred at Ti/Al3Ti interface with the reaction time prolonging, while at Al/Al3Ti interface, it was an increased tendency; for the fraction of low angle grain boundary, at Ti/Al3Ti interface, it decreased with a longer reaction time, while at Al/Al3Ti it increased, which resulted from continuous dynamic recrystallization and discontinuous dynamic recrystallization mechanism, respectively. The Al3Ti grains close to Ti exhibited the (100)〈001〉 and (110)〈001〉 textures but no texture existed at Al3Ti close to Al. Meanwhile, the texture strength decreased due to the effect of recrystallization.