【摘 要】
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The nucleation and growth of grains in a series of Al-based alloys produced by electrolysis are observed under SEM. The atomicTi/Al ratios of the nuclei and the
【机 构】
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Laboratory of Materials Physics of Henan Province,Department of Materials Engineering
论文部分内容阅读
The nucleation and growth of grains in a series of Al-based alloys produced by electrolysis are observed under SEM. The atomicTi/Al ratios of the nuclei and the distribution of Ti at certain points are analyzed by point EDS. The particles in differentatomic Ti/Al ratios might act as the nuclei of α-Al. At the early stage of growth, the spherical Ti-enriched regions might formaround these particles within very limited temperature ranges in which the reactions such as the peritectic reactions etc occur.At the latter stage of growth, the dendrites freely develop in the radial orientations, and the concentration of Ti decreaseslinearly along the dendrite arm and becomes negligible in the region near the periphery of the dendrite. It is believed that thenucleation is closely related with the number and dispersion of primary spherical areas in the melts, and the segregation of Tileads to the free growth of dendrite, which is necessary for the formation of equiaxial grains.
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