The invention discloses the internal structures and processes to synthesize the structure of self-healing materials, especially metallic materials, metal matrix micro and nanocomposites. Self-healing is imparted by incorporation of macro, micro or nanosize hollow reinforcements including nanotubes, filled with low melting healing material or incorporation of healing material in pockets within the metallic matrix; the healing material melts and fills the crack. In another concept, macro, micro and nanosize solid reinforcements including ceramic and metallic particles, and shape memory alloys are incorporated into alloy matrices, specially nanostructured alloy matrices, to impart self healing by applying compressive stresses on the crack or diffusing material into voids to fill them. The processes to synthesize these self-healing and nanocomposite structures, including pressure or pressureless infiltration, stir mixing and squeeze casting in addition to solid and vapor phase consolidation processes are part of this invention.