CoryPad;
The ASM Metals Handbook, Desk Edition, 2nd Ed (Appendix 2, page 113) lists the allotropic transformation at 1 atm for elemental cobalt as alpha phase(FCC crystal structure) above 422 deg C , and epsilon phase (HCP crystal structure)at and below this temperature.
On page 616 of the ASM Metals Handbook, Desk Edition, 2nd Ed, the HCP crystal structure is once again reported at temperatures below 417 deg C, at and above this temperature and up until the melting point, the FCC crystal structure is reported. I would think it was beta phase as well until I looked it up out of curiosity.