An investigation of the Al-Re phase diagram

The Al-Re binary system was studied by analysing are-melted samples with op tical microscopy, scanning electron microscopy, energy dispersive X-ray spe ctroscopy and X-ray diffraction. There was good agreement with the most rec ent published phase diagram up to 25 at.% Re. The following phases were ide ntified to form from solidification: (Al), Al12Re, Al6Re, Al4Re, Al3Re (of nominal composition Al11Re4), Al2Re3, Al2Re and (Re). The (Al)+Al12Re eutec tic was confirmed, and a previously unreported eutectic: L-->Al3Re+Al2Re3 w as identified. The remaining reactions were peritectic, except for the form ation of Al3Re, which was congruent. Phase limits were derived for all phas es, except Al12Re. The solubility limit for (Re), similar to 83 at.% Re, wa s found to correspond with the composition for the Al5Re24, and the h.c.p. structure was confirmed by X-ray diffraction. (C) 1999 Elsevier Science S.A . All rights reserved.