S18  Processos Mecânico-Metalúrgicos    Titulo: OBTENÇÃO DE ESTRUTURA REOFUNDIDA DA LIGA AL-4,5WT%CU: COMPARAÇÃO ENTRE O ULTRA-REFINO E A AGITAÇÃO ELETROMAGNÉTICA.   Resumo : OBTENTION RHEOCAST STRUCTURE FOR AL-4,5WT%CU ALLOY: COMPARISON ULTRA-REFINING AND ELECTRO-MAGNETIC STIRRING ABSTRACT: THE PRESENT WORK ANALYSES THE MECHANISMS INVOLVED IN THE FORMATION OF THE RHEOCAST STRUCTURE (GLOBULAR) FOR THE AL-4,5WT%CU ALLOY, PRODUCED BY ELECTRO-MAGNETIC STIRRING (EMS) OF THE LIQUID DURING SOLIDIFICATION, UNDER THE FOLLOWING BASIC CONDITIONS: POURING TEMPERATURES OF 750 AND 800°C WITH AND WITHOUT ADDITION OF A GRAIN REFINER. THE OBJECTIVE IS TO DIRECTLY COMPARE BETWEEN THE ELECTRO - MAGNETIC STIRRING AND ULTRA - REFINING AS METHODS OF OBTAINING RHEOCAST MATERIALS, AS WELL AS TO VERIFY THE POSSIBILITY OF USING THESE METHODS TOGETHER. THE EXPERIMENTAL APPARATUS WAS MADE OF A WRAPPED METALLIC INGOT MOULD SURROUNDED BY A SEQUENCE OF INDUCTION COILS AND A POWER SOURCE THAT GENERATED NA ESTIMATED POWER OF ELECTROMAGNETIC FIELD WITH 26WATTS, WHICH WAS ENOUGH FOR A FIXED AMOUNT OF 1KG OF MOULTING METAL). THE MACRO AND MICROSTRUCTURES INGOTS OBTAINED HAD THE CHARACTERISED BY OPTICAL MICROSCOPY TO MEASURE THE GLOBULAR SIZE AND THE ROUNDNESS OF THE GLOBULAR STRUCTURES (TO VERIFY THE EFFICIENCY OF THE GLOBULARIZATION). THE PRINCIPAL OBJECTIVE IS TO COMPARE ELECTRO-MAGNETIC STIRRING AND ULTRA-REFINING TO DETERMINE THE BETTER STRUCTURE (LEVEL OF GLOBULARIZATION), DETERMINING THE FACTOR OF LARGER INFLUENCE: THE GRAIN REFINER OR THE ELECTRO-MAGNETIC INDUCED FIELD. KEY-WORDS: RHEOCASTING, ALUMINIUM-COPPER ALLOYS, ELECTRO-MAGNETIC STIRRING, ULTRA-REFINING.     Autores : Paes, Marcelo 0 Zoqui, Eugênio José     Trabalho Completo :   COBEM99 | Comissão  Organizadora | Palestras | Sessões Técnicas | Autor | Simpósios e Sessões Especiais | Revisores |  Título  dos  Trabalhos | Local