The present invention provides for assemblies comprising metal matrix composite bars where the bars only intermittently have mutual contact. Minimally two bars of metal matrix composite are joined, for example by lap joints, or by the use of incorporated tabs and slots or over-lapping slots, at areas of mutual contact to form the assemblies. The metal matrix composite assemblies of the present invention may be readily assembled to provide structures, supports, or sub-assemblies, and the like, that may exhibit high strength and stiffness coupled with relatively low mass. Additionally, such assemblies may withstand exposure to elevated temperatures higher than can be tolerated by polymeric composites. Such assemblies are expected to be particularly suitable for lightweight, stiff support structures for space booms, satellite structures, mirror backings, solar panel supports, wall reinforcement, and the like.