WE CLAIM:
1. A method for direct writing of single crystal super alloys and
metals, the method comprising:
heating a substrate (23) to a predetermined temperature using a first heater
(24), wherein the predetermined temperature is below the substrate’s melting
point;
using a laser (26) to form a melt pool (34) on a surface of the substrate
(23), wherein the substrate (23) is positioned on a base plate (22), and wherein the
laser (26) and

5. The method as claimed in claim 1, further comprising:
using a cooling source (60) in communication with the controller (36) to
adjust the temperature of the melt pool (34).
6. A method for direct writing of single crystal super alloys and
metals, the method comprising:
heating a substrate (23) to a predetermined temperature using a first heater
(24), wherein the predetermined temperature is below the substrate’s melting
point;
using a laser (26) to form a melt pool (34) on a surface of the substrate
(23), wherein the substrate (23) is positioned on a base plate (22), and wherein the
laser (26) and the base plate (22) are movable relative to each other, the laser (26)
being used for direct metal deposition;
introducing a superalloy powder to the melt pool (34);
measuring the temperature of the melt pool (34);
receiving the temperature measured at a controller (36); and
using a cooling source (60) in communication with the controller (36) to
adjust the temperature of the substrate (23).
7. The method as claimed in claim 6, wherein the cooling source (60)
is a cooling gas (62) directed at the substrate (23) with a variable gas flow.
8. The method as claimed in claim 6, wherein the cooling source (60)
is a furnace, and wherein the substrate is positioned within the furnace (60).
9. An apparatus (20) for direct writing of single crystal super alloys
and metals comprising:
a laser (26) having a power output;
a base plate (22) configured for holding a substrate (23) thereon;
a DMD head (28) configured to supply a stream of superalloy powder (32)
onto the substrate (23);

an induction heating source (24) positioned to heat the substrate (23) on
the base plate (22) to a predetermined temperature;
at least one of an auxiliary heating means (41) and a cooling means (60);
and
a controller (36) for controlling the at least one of the auxiliary heating
means (41) and the cooling means (60), wherein the controller (36) is responsive
to a measured temperature of at least one of a melt pool (34) on the substrate (23)
and the substrate (23).
10. The apparatus as claimed in claim 9, comprising the cooling means
(60), wherein the cooling means (60) comprises a furnace into which the substrate
(23) is positioned.