A method of fabricating a component having a directionally solidified microstructure or a single crystal microstructure, the method comprising the steps of: depositing a nickel-base superalloy powder with a composition comprising gamma nickel solid solution and gamma prime Ni 3 Al solid solution phases onto a seed crystal (305; 602), the seed crystal having a predetermined primary orientation; melting the deposited nickel-base superalloy powder and a portion of the seed crystal at a superliquidus temperature to form an initial layer, the initial layer having the predetermined primary orientation; heat treating the initial layer at subsolvus temperatures to precipitate particles of the gamma prime solid solution phase; depositing additional nickel-base superalloy powder over the initial layer after heat treating the initial layer at subsolvus temperatures to precipitate particles of the gamma prime solid solution phase; melting the deposited additional nickel-base superalloy powder and a portion of the initial layer at a superliquidus temperature to form a successive layer (802, 902, 903), the successive layer having the predetermined primary orientation; heat treating the successive layer at a subsolvus temperature to precipitate particles of the gamma prime solid solution phase; and repeating the steps of depositing additional nickel-base superalloy powder after heat treating the successive layer at subsolvus temperatures to precipitate particles of the gamma prime solid solution phase, melting the deposited additional nickel-base superalloy powder and a portion of the successive layer at the superliquidus temperature, and heat treating the successive layer at the subsolvus temperature to form the component; wherein the steps of melting at the superliquidus temperature and heat treating at the subsolvus temperature are performed using a laser beam or an electron beam. depositing a nickel-base superalloy powder with a composition comprising gamma nickel solid solution and gamma prime Ni 3 Al solid solution phases onto a seed crystal (305; 602), the seed crystal having a predetermined primary orientation; melting the deposited nickel-base superalloy powder and a portion of the seed crystal at a superliquidus temperature to form an initial layer, the initial layer having the predetermined primary orientation; heat treating the initial layer at subsolvus temperatures to precipitate particles of the gamma prime solid solution phase; depositing additional nickel-base superalloy powder over the initial layer after heat treating the initial layer at subsolvus temperatures to precipitate particles of the gamma prime solid solution phase; melting the deposited additional nickel-base superalloy powder and a portion of the initial layer at a superliquidus temperature to form a successive layer (802, 902, 903), the successive layer having the predetermined primary orientation; heat treating the successive layer at a subsolvus temperature to precipitate particles of the gamma prime solid solution phase; and repeating the steps of depositing additional nickel-base superalloy powder after heat treating the successive layer at subsolvus temperatures to precipitate particles of the gamma prime solid solution phase, melting the deposited additional nickel-base superalloy powder and a portion of the successive layer at the superliquidus temperature, and heat treating the successive layer at the subsolvus temperature to form the component; wherein the steps of melting at the superliquidus temperature and heat treating at the subsolvus temperature are performed using a laser beam or an electron beam.