The structural stability of the intermetallics AlTi3, Al2Ti, Al3Ti4 and Al3Ti in the Al-Ti system has been investigated using density functional theory （DFT） and density functional perturbation theory （DFPT）. The calculated ground-state convex hull is in agreement with the experimental researches. Al3Ti4 （hP7） is metastable at 0 K and may be stabilized as the temperature increases due to the effects of the vibration entropy. For Al2Ti, r-Al2Ti is stable at 0 K and h-Al2Ti is stabilized by the vibration entropy at high temperatures. Al3Ti （tI16） is unstable considering vibration effects and Al3Ti （tI8） is the most stable structure at 0 K.
Hui Zhang and Shaoqing Wang Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China
