Laser fabrication of discontinuously reinforced metal matrix composites

Disclosed are reinforced metal matrix composites and methods of shaping powder materials to form such composites. Articles of manufacture are formed in layers by a laser fabrication process. In the process, powder is melted and cooled to form successive layers of a discontinuously reinforced metal matrix. The matrix exhibits fine grain structure with enhanced properties over the unreinforced metal, including higher tensile modulus, higher strength, and greater hardness. In some preferred embodiments, an in-situ alloy powder, a powder metallurgy blend, or independently provided powders are reinforced with boron and/or carbon to form the composite.