A method of making a component, comprising: depositing a metallic powder on a workplane; directing a beam from a directed energy source to fuse the powder in a pattern corresponding to a cross-sectional layer of the component; repeating in a cycle the steps of depositing and fusing to build up the component in a layer-by layer fashion; and during the cycle of depositing and melting, using an external heat control apparatus (144, 146, 150, 154) separate from the directed energy source, characterized in that the external heat control apparatus (144, 146, 150, 154) controls both the temperature and the heating rate of the component during the cycle of depositing and fusing to maintain a predetermined temperature profile of the component, such that the resulting component has a directionally-solidified or single-crystal microstructure, and another induction heater is to be used to more directly control remelt and solidification of the component by moving the induction heater into an extended position over a freshly directed-energy-melted layer of the component and activating to heat that layer as desired; and after completion of the desired heating cycle the induction heater is retracted out of the way of the rest of the apparatus so that the next layer of powder could be applied and directed-energy melted to the layer below. depositing a metallic powder on a workplane; directing a beam from a directed energy source to fuse the powder in a pattern corresponding to a cross-sectional layer of the component; repeating in a cycle the steps of depositing and fusing to build up the component in a layer-by layer fashion; and during the cycle of depositing and melting, using an external heat control apparatus (144, 146, 150, 154) separate from the directed energy source, characterized in that the external heat control apparatus (144, 146, 150, 154) controls both the temperature and the heating rate of the component during the cycle of depositing and fusing to maintain a predetermined temperature profile of the component, such that the resulting component has a directionally-solidified or single-crystal microstructure, and another induction heater is to be used to more directly control remelt and solidification of the component by moving the induction heater into an extended position over a freshly directed-energy-melted layer of the component and activating to heat that layer as desired; and after completion of the desired heating cycle the induction heater is retracted out of the way of the rest of the apparatus so that the next layer of powder could be applied and directed-energy melted to the layer below. during the cycle of depositing and melting, using an external heat control apparatus (144, 146, 150, 154) separate from the directed energy source, characterized in that the external heat control apparatus (144, 146, 150, 154) controls both the temperature and the heating rate of the component during the cycle of depositing and fusing to maintain a predetermined temperature profile of the component, such that the resulting component has a directionally-solidified or single-crystal microstructure, and another induction heater is to be used to more directly control remelt and solidification of the component by moving the induction heater into an extended position over a freshly directed-energy-melted layer of the component and activating to heat that layer as desired; and after completion of the desired heating cycle the induction heater is retracted out of the way of the rest of the apparatus so that the next layer of powder could be applied and directed-energy melted to the layer below.