Method of manufacturing billet for plastic working for producing composite member, and billet manufactured thereby

A method of manufacturing a billet for plastic working for producing a composite member, the method comprising:

• (A) ball-milling aluminum powder and carbon nanotubes (CNT) to produce a plurality of composite powders;
• and
• (B) preparing a multi-layered billet using the plurality of composite powders,
• wherein in the step (B), the preparing of the multi-layered billet comprises subjecting the composite powder to spark plasma sintering performed at a pressure of 30 to 100 MPa and a temperature of 280° C. to 600° C. for a duration of 1 second to 30 minutes,
• wherein the multi-layered billet comprises a first billet having a can shape and serving as a second shell layer;
• a second billet disposed inside the first billet as a first shell layer;
• and a third billet disposed inside the second billet as a core layer,
• wherein the first billet is made of aluminum, and the second billet comprises one of the plurality of composite powders and the third billet comprise another one of the plurality of the composite powders, and
• wherein the second billet comprises 0.09 to 10 parts by volume of the carbon nanotubes with respect to 100 parts by volume of the aluminum powder, and the third billet comprises 0.08 part by volume of the carbon nanotubes with respect to 100 parts by volume of the aluminum powder.