Avaliação da tixoconformabilidade das ligas AA7075 a AA7004 / Evaluation of thixoformability of AA7075 and AA7004 alloys

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The goal of this work was to evaluate the thixoformability of AA7075 and AA7004 alloys, including all the stages process: characterization in terms of micro and macrostructures; characterization of the rheological behavior; and the tixoforging process in an eccentric press using a matrix-type close. The alloys were submitted to re-heating treatment for 0s, 30s, 90s and 210s in two conditions of solid fraction, 45% and 60%; had been realized tests of viscosity under the same conditions and thixoforging tests with the time 210s and solid fraction of 45%. Finally, had been the mechanical properties of the thixoforged piece. Re-heating treatment times promote the solid phase particles globularization, from that the best results of viscosity been reached for alloys treated during 210s and solid fractions of 45%: AA7075 and AA7004 alloys presented resulted of apparent viscosity of 103 a 105 (Pa.s), literature according to materials that if find in this index of viscosity possess the similar behavior the casting glass and demonstrate high conformability. To be outstanding the AA7004 alloy with the time of 210s and solid fraction of 45% got optimum result of apparent viscosity, (6,52E+3 Pa.s), revealing more viable the process thixoforming. The thixoforged piece presented total fulfilling of the matrix, however presented results low the mechanical properties in terms the resistance and elongation when compared the original casting structures

ASSUNTO(S)

rheology aluminun alloys casting ligas de aluminio viscosidade ligas de aluminio - tratamento termico viscosity fundição reologia aluminun alloys

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