Evaluation of Functionally Graded Ceramic Crucible for Induction Melting of TiAl Based Alloys

• Tipo: Artigo em Livro de Atas de Conferência Internacional
• Data: 2013

Autores

Gomes, F (Autor) Outra; Barbosa, J (Autor) Outra; Carlos Silva Ribeiro (Autor) FEUP

Ata de Conferência Internacional

Título: ADVANCED MATERIALS FORUM VI, PTS 1 AND 2

Páginas: 769-774

6th International Materials Symposium (MATERIALS 2011)/15th Meeting of SPM

Guimaraes, PORTUGAL, APR 18-20, 2011

Indexação

ISI Web of Knowledge - 0 Citações

Scopus - 4 Citações

Outras Informações

ID Authenticus: P-005-3PW

DOI: 10.4028/www.scientific.net/msf.730-732.769

Abstract (EN): During the last years a very significant effort to develop a melting crucible for induction melting of Ti based alloys at competitive cost has been carried out by many researchers, where the authors are included. Results obtained so far have shown that no material accomplishes the melting crucibles two main demands: inertness facing titanium alloys and suitable/enough thermal-shock resistance. Until now, yttrium and calcium oxides were those materials that performed best on what concerns to thermodynamic stability. However, in both cases, crucibles thermal-shock resistance was very poor, and there are references to crucibles that cracked during melting. Besides, calcium oxide reveals manipulation problems, due to its high higroscopicity. This paper concerns to the evaluation of zircon based crucibles with Y2O3 inner layer for induction melting of TiAl based alloys. A novel multi layered crucible production technique based in a centrifugally assisted slip casting process followed by a sintering operation is described, and results concerning to crucibles porosity and wall composition and morphology are presented. Crucibles obtained in different processing conditions were used to melt a Ti48Al alloy which was poured in graphite moulds. Experimental results include alloy chemical contamination with residual elements, mainly yttrium and oxygen, microhardness measurement and the presence of yttrium oxide and zircon inclusions in the cast samples. Results concerning to the crucibles behaviour are also presented with particular attention to cracks development. The Y2O3 crucible layer was found to suffer some erosion and be slightly dissolved by the molten alloy and the extent of those phenomena depends on the porosity of the layer surface, for fixed experimental melting conditions.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 6