Abstract: A composite material suitable for use as an armor includes a first layer of a metallic material and a second layer, metallurgically bonded with the first layer. The second layer includes a matrix of the material of the first layer and a plurality of brittle particles dispersed in the matrix. A method for making a composite structure suitable for use as an armor from a workpiece of a metallic material includes the steps of plasticizing a fractional thickness of the workpiece using a friction stir process, introducing a plurality of brittle particles into the plasticized, fractional thickness of the workpiece, and dispersing the plurality of brittle particles into the plasticized, fractional thickness of the workpiece using the friction stir process.