Mechanical milling (MM) and a combination of MM and temperature heating were used to synthesize the intermetallic MmNi5 and a MmNi5-Ni mixture, respectively. The process evolution with time was analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). SEM was used to characterize size and morphology of particles in order to reveal the governing mechanisms during the milling of each system. X-ray diffraction (XRD) was utilized to determine strain and crystallite size changes introduced by milling. The effects of integrated milling time on the sorption properties of the MmNi5-Ni mixture were analyzed. Results were correlated to defects introduced into microstructure. A comparison of the final characteristics of alloys obtained in each case is also shown.