Abstract
A metallographic study has been made of an Al-1.78 wt % Hf alloy after rapid solidification, and after high temperature annealing of the as-cast alloy. After solidification, Hf stays in supersaturated solid solution with a rather inhomogeneous distribution. On annealing, spheres and dendrites of an intermediate Al3Hf phase withLI 2 structure, and perfectly coherent with the matrix, are formed. The spheres form by a continuous, the dendrite by a discontinuous precipitation reaction. After continued annealing theLI 2 structure is replaced by a laminated structure ofLI 2 andDO22, whereDO22 is the equilibrium structure of Al3Hf. The precipitation reactions in the systems Al-Hf and Al-Zr are compared.
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Ryum, N. Precipitation in an Al-1.78 wt % Hf alloy after rapid solidification. J Mater Sci 10, 2075–2081 (1975). https://doi.org/10.1007/BF00557486
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DOI: https://doi.org/10.1007/BF00557486