Coarsening behavior of Ll2 structured Al3(Zrx V1−x) precipitates in rapidly solidified AlZrV alloy
1987; Pergamon Press; Volume: 21; Issue: 7 Linguagem: Inglês
10.1016/0036-9748(87)90143-8
ISSN1878-2663
AutoresYu‐Ru Chen, M. E. Fine, J. Weertman, R. E. Lewis,
Tópico(s)High Temperature Alloys and Creep
ResumoA supersaturated Al alloy with 1.1 wt.% of Zr and 1.7 wt.% of V, which gives rise to about 5 vol.% of metastable Ll/sub 2/ phase after aging, was prepared by melt spinning. Both spherical and cellular Ll/sub 2/ structured precipitates form during aging. A higher aging temperature suppresses the cellular and favors the spherical Ll/sub 2/ precipitates. Because of the growth of grain boundary Al/sub 10/V particles during aging, precipitate free zones (PFZs) form adjacent to the grain boundaries. The average PFZ width is proportional to the square root of the annealing time. A slow volumetric particle coarsening rate of 1.0 x 10/sup -28/ m/sup 3//h at 425/sup 0/C was measured for the Ll/sub 2/ structured Al/sub 3/(Zr/sub .25/V/sub .75/) precipitate. An interfacial energy of 0.03 J/m/sup 2/ is calculated for the Ll/sub 2/ particles. The resistance at 425/sup 0/C to transformation to the stable DO/sub 23/ form and to Ostwald ripening suggests that the phase is a promising dispersoid for high temperature Al alloys. Preliminary creep results support this suggestion.
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