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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Transient directional solidification of a eutectic Al-Si-Ni alloy: Macrostructure, microstructure, dendritic growth and hardness

Texto completo
Autor(es):
Kakitani, Rafael [1] ; Cruz, Clarissa B. [1] ; Lima, Thiago S. [1] ; Brito, Crystopher [2] ; Garcia, Amauri [1] ; Cheung, Noe [1]
Número total de Autores: 6
Afiliação do(s) autor(es):
[1] Univ Campinas UNICAMP, Dept Mfg & Mat Engn, BR-13083860 Campinas, SP - Brazil
[2] Sao Paulo State Univ UNESP, Campus Sao Joao da Boa Vista, BR-13876750 Sao Joao Da Boa Vista, SP - Brazil
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: MATERIALIA; v. 7, SEP 2019.
Citações Web of Science: 3
Resumo

The Al-11 wt%Si-5 wt%Ni eutectic alloy was directionally solidified (DS) under transient heat flow conditions at cooling rates in a range of about 1-25 degrees C/s along the length of the casting. For comparison purposes binary Al-11 wt%Si and Al-5 wt%Ni alloys were also solidified under similar experimental conditions. Initially characterized by columnar grains, the macrostructure of the ternary DS alloy casting evolved during solidification to a columnar to equiaxed transition (CET) at critical cooling rates of about 1.3-1.6 degrees C/s, i.e. more than 7 times higher than the CET critical value determined in the literature for Al-Ni and Al-Si alloys. The microstructure of the ternary alloy casting is shown to be constituted by primary Si crystals and alpha-Al dendritic branches surrounded by the eutectic phase (alpha-Al+Si+Al3Ni), with the Al3Ni phase having initially a plate-like morphology, which with the decrease in the solidification kinetics, evolved to a fishbone morphology. The pertinent scaling laws representing the dendritic growth of the eutectic ternary alloy, properly compared to those of the examined Al-Si and Al-Ni binary alloys are outlined. The scale of the dendritic alpha-Al phase is shown to affect the Vickers hardness (HV) along the length of the ternary eutectic alloy casting, and a Hall-Petch type equation is proposed relating HV to the secondary dendritic arm spacing. (AU)

Processo FAPESP: 17/15158-0 - Caracterização microestrutural e de propriedades na avaliação de ligas para contato térmico interfacial
Beneficiário:Amauri Garcia
Linha de fomento: Auxílio à Pesquisa - Regular