| The purpose of this paper was observation of and kinetic analysis of the precipitation process in heat-resistant alloys to improve the mechanical properties and the thermal properties. Al-Cr alloys were rapidly solidified into a ribbon shape by a melt spinner. The decomposition process of rapidly solidified Al-Cr alloys were examined by means of TEM, X-ray diffraction and micro-Vickers hardness. As a result of an isothermal aging of massively transformed Al-3.43wt.%Cr alloy at 450℃, subgrains formed by polygonization process. With more aging, precipitation occurred on the subgrain boundaries. The decomposition process of massively transformed Al-3.43wt%Cr alloy was analyzed by the cylindrical precipitation model. In the initial stave, n in the Johnson-Mehl-Avrami equation is 2.98 corresponding to the characteristics of the interface-controlled growth of a fixed number of particles. In the middle and the final stage, n is 1.85 corresponding to the characteristics of the diffusion-controlled growth of a fixed number of particles. |
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