A method of manufacturing a heterogeneous composite material thin plate, the method comprising:
- (a) preparing a composite powder by ball-milling an aluminum or aluminum alloy powder and a carbon nanotube powder;
- (b) manufacturing a multilayer billet containing the composite powder and comprising a core layer and two or more shell layers surrounding the core layer, wherein the core layer is made of the composite powder or an aluminum alloy,
- each of the shell layers excluding the outermost shell layer is made of the composite powder, and
- the outermost shell layer is made of (i) aluminum or aluminum alloy powder or (ii) the composite powder;
- (c) manufacturing an extruded material by extruding the multilayer billet;
- and
- (d) shaping the extruded material into a thin plate by rolling.