Al-Ti was electrodeposited from 1-ethyl-3-methyl-imidazolium chloride (EMIC)-AlCl3 ionic liquid containing TiCl4 on a copper working electrode using a potentiostatic or potential-pulse polarization. Deposits of Al-Ti alloy was obtained beneath the loose precipitate composed of mainly insoluble titanium chloride. Potential-pulse polarization that switched the potential between the two cathodic reduction potential of the multistep reduction of Ti ions improved the efficiency of electrodeposition of Al-Ti alloy. The ratio of Al-Ti alloy against the loose precipitate was increased by adding the Mg powder to the ionic liquid bath. It was supposed that Ti[IV] was reduced to Ti[II] by the substitutional dissolution of Mg and the resultant Ti[II] species such as TiCl42- contributed the electrodeposition of Ti. Simultaneous deposition of Al protected as-deposited Ti from re-oxidation (chlorination) by encapsulation them in the Al-Ti alloy. Although the deposition efficiency increased using Mg additive, the atomic content of Ti in Al-Ti deposits was reduced from ca. 21% for the bath absent of Mg powder to ca. 10% for the bath containing Mg. The decrease in the Ti content in the deposits was probably due to the insufficient supply rate of Ti[II] ions compared to the deposition rate of Al. (C) 2019 The Electrochemical Society.