Critical states and phase diagram in the packing of uniform spheres

This paper presents a study of the structural transition of the packing of uniform spheres with a wide range of packing fractions. Several critical states are identified including the onset of local jamming, onset of global jamming and maximally random jammed (MRJ) states. With the increase of packing fraction Ï, the packing structure transforms from one-dimensional chains to two-dimensional triangles and finally three-dimensional tetrahedra, correspondingly undergoing phase changes from non-jamming to local jamming, global jamming, MRJ and finally crystal structure. There is a competition between FCC (face-centred cubic) and HCP (hexagonal closed packed) in the transition from disordered to ordered structure with the increase of Ï. HCP can transform to FCC after reaching its maximum at Ï=0.7.