Zhou and Bakker (Acta Metall Mater 1994; 42:3009) reported the formation of progressively disordered L1 2 and also a distinct disordered fcc solid solution on ball-milling Ni 3 Si with the ordered L1 2 structure. The formation of disordered phases was accompanied by a decrease in lattice parameter, 0.53% for partially disordered L1 2 at a 1ro parameter of ~0.56, and as much as 2.44% for the disordered fcc. These contractions were attributed to antisite defects. This behaviour is at variance with the generally observed small expansion on such disordering. Further, of the several L1 2 structures disordered by mechanical means, this is the only observation of the co-existence of a disordered L1 2 and a distinct disordered fcc phase. These results have been re-interpreted to show that the diffraction peak identified by them as characteristic of fcc in fact belongs to hexagonal Ni 3 1 Si 1 2 phase, thus accounting for the major anomaly. The small decrease on partially disordering L1 2 is possibly due to an increase in the valence of Si.