| 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 |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |