Mechanical Blocking Mechanism for the Columnar to Equiaxed Transition

Autor(es)

Biscuola, V. B. ^[1] ; Martorano, M. A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Met & Mat Engn, BR-05508900 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE; v. 39A, n. 12, p. 2885-2895, DEC 2008.
• Citações Web of Science: 30

Resumo

Mechanical blocking of the columnar front during the columnar to equiaxed transition (CET) is studied by quantitatively comparing the CET positions obtained with one stochastic model and two deterministic models for the unidirectional solidification of an Al-7 (wt pct) Si alloy. One of the deterministic models is based on the solutal blocking of the columnar front, whereas the other model is based on the mechanical blocking. The solutal-blocking model and the mechanical-blocking model with the traditional blocking fraction of 0.49 give columnar zones larger than those predicted with the stochastic model. When a blocking fraction of 0.2 is adopted, however, the agreement is very good for a range of nucleation undercoolings and number density of equiaxed grains. Therefore, changing the mechanical-blocking fraction in deterministic models from 0.49 to 0.2 seems to model more accurately the mechanical-blocking process that can lead to the CET. (AU)

• Processo FAPESP: 03/08576-7 - Modelagem matemática da solidificação de ligas binárias sob efeito de convecção natural no líquido e movimentação da fase sólida
• Beneficiário: Marcelo de Aquino Martorano
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores