Experimental results are presented on laser alloying of Co nanorods with Al spherical nanoparticles by laser exposure of their mixture in liquid ethanol. It is demonstrated that the initial morphology of the nanoparticles is modified upon laser exposure. The Co nanorods are transformed into Co nanospheres covered by a layer of Al. The evolution of the size distribution is studied as a function of the time of laser exposure. The average size of the nanoparticles has a maximum level with a corresponding optimal irradiation time. The results are discussed from the viewpoint of the interaction of molten nanoparticles inside a cavitation bubble filled with a liquid vapor.