The columnar to equiaxed transition in the directional solidification of aluminum based multicomponent alloys

Rem: Revista Escola de Minas

Otávio Lima Rocha¹  Laércio Gouvea Gomes¹  Daniel Joaquim Conceição Moutinho¹  Ivaldo Leão Ferreira¹  Amauri Garcia¹ 

关键词: Directional solidification;    Macrostructures;    Columnar/equiaxed transition;    Al-Si-Cu alloys;    solidificação direcional;    macroestruturas;    ransição colunar/equiaxial;    ligas Al-Si-Cu;   

DOI  :  10.1590/0370-44672015680237

来源: SciELO

【 摘 要 】

In this work the columnar to equiaxed transition (CET) was experimentally investigated in the unidirectional solidification of three aluminum based multicomponent alloys (Al-nSi-3Cu), with "n" equal to 5.5, 7.5 and 9 wt.%. The main parameters analyzed include the tip temperature gradient (GL), tip growth rate (VL), tip cooling rate (TR) and Si content. A water-cooled solidification experimental setup was developed, and specimens were solidified under unsteady state heat flow conditions. It is shown that for the alloys examined, the solute concentration influences the position of the CET, which occurs for an average cooling rate of about 1.17 0C/s. A comparative analysis between the results of this work and those from literature proposed to analyze the CET during upward vertical solidification of Al-Si alloys is reported and the results show that the end of the columnar region is abbreviated as a result of seven times higher critical cooling rate than that verified for Al-Si alloys.

【 授权许可】

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