COBEM99

S19 Usinagem dos Materiais

Title:

INDICAÇÃO DO MODO DE REMOÇÃO EM CERÂMICAS AVANÇADAS ATRAVÉS DA EMISSÃO ACÚSTICA (EA) INDICATION OF REMOVAL MODE IN ADVANCED CERAMICS BY THE ACOUSTIC EMISSION (AE)

Summary :

INDICATION OF REMOVAL MODE IN ADVANCED CERAMICS BY THE ACOUSTIC EMISSION (AE) SUMMARY. IN THIS WORK IS PRESENTED THE BEHAVIOUR OF ACOUSTIC EMISSION (AE) IN ADVANCED CERAMICS SCRATCHING, TAKING THE ALUMINA 96% AS THE MAIN REPRESENTATIVE. IN OPPOSITION TO THE ADVANCED CERAMICS, WHICH HAS GRANULAR STRUCTURE, IT’S ALSO USED THE GLASS AS NON-GRANULAR CERAMIC MATERIALS. THE USED ALUMINA IS CHARACTERIZED BY AN IRREGULAR MICROSTRUCTURE COMPOSED BY GRAINS OF HETEROGENEOUS SIZE. TWO TYPES OF DIFFERENT SCRATCHING WERE CARRIED OUT USING VARIABLE DEPTHS AND CONSTANT LOAD. IN THE FIRST, THE PARAMETER PRINCIPAL STUDIED IS THE SCRATCHING DEPTH WHEREAS THE SECOND IS LOAD AND ACCUMULAD DAMAGE EFECT DUE THE REPEATED PASSES ON THE SAME TRACK. AS A RESULT, IT WAS OBSERVED THAT AE SIGNALS AND TIME-FREQUENCY ANALYSIS IS COMMENSURATE WITH THE DAMAGES IN THE MATERIAL. ALSO IS SHOWN THAT THERE ARE DIFFERENCES IN THE AE SIGNALS OF THE SCRATHES MADE IN ALUMINA AND THE GLASSES, DUE TO THE DIFFERENT REMOVAL MECHANISMS ASSOCIATED WITH THE STRUCTURE OF THESE MATERIALS. IT IS STILL OBSERVED AN INCREASE OF AE SIGNAL LEVEL WITH THE GRADATIVE INCREASE OF THE NUMBER OF REPEATED PASSES DUE TO THE ACCUMULATION OF DAMAGES IN THE MATERIAL. KEYWORDS: ADVANCED CERAMICS, SCRATCHING, ACOUSTIC EMISSION, REMOVAL, CRACKS.

Author :

Coelho, Reginaldo Teixeira
Fortulan, Carlos Alberto
Oliveira, João Fernando Gomes
Sanchez, Luiz Eduardo de Angelo

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