Encontrados 5 documentos, a visualizar página 1 de 1
Influence of indirect ultrasonic vibration on the microstructure and mechanical...
Puga, Hélder; Barbosa, J.; Costa, Sónia; Ribeiro, Carlos Silva; Pinto, A. M. P.; Prokic, MiodragThe influence of high intensity ultrasound (US) propagating through a steel mold on the microstructure and mechanical properties of die-cast AlSi9Cu3, for different levels of electric power and at different distances to the waveguide/mold interface. The influence of those parameters on the morphology of -Al and eutectic Si and on the volume of porosity were investigated and characterized. The morphological ch...
Evaluation of ultrasonic aluminium degassing by piezoelectric sensor
Puga, Hélder; Gabriel, Joaquim; Barbosa, J.; Seabra, Eurico; Ribeiro, Carlos Silva; Prokic, MiodragThe purpose of this work was the development of a reliable technique to evaluate the intensity of acoustic cavitation during degassing of aluminium melts and to use it to select the optimum processing time for an envisaged degassing efficiency. A high sensitivity piezoelectric disk type device was used as a sensing feedback in water and liquid AlSi9Cu3 alloy. The signal acquisition and processing was carried ou...
Influence of ultrasonic melt treatment on microstructure and mechanical propert...
Puga, Hélder; Costa, Sónia; Barbosa, J.; S. Ribeiro, Carlos; Prokic, MiodragA novel MMM (Multi-frequency, Multimode, Modulated) ultrasonic (US) technology was used to refine the as cast microstructure and improve the mechanical properties of a AlSi9Cu3 alloy. Ultrasonic vibration was isothermally applied to the melt for 120 seconds at different temperatures slightly above the liquidus temperature of the alloy, using different electric power values, before pouring into a metallic mould....
The combined effect of melt stirring and ultrasonic agitation on the degassing ...
Puga, Hélder; Barbosa, J.; Teixeira, J. Carlos; Seabra, Eurico; Ribeiro, Carlos Silva; Prokic, MiodragThe combined effect of high intensity ultrasound and melt stirring on the degassing of AlSi9Cu3 using simultaneously the novel MMM (Multi-frequency Multimode Modulated) ultrasonic technology to promote cavitation, and low frequency mechanical vibration to induce melt stirring, was studied. On a first stage single low frequency mechanical vibration experiments were carried out in water in order to visualize and ...
The inluence of processing variables on the ultrasonic degassing of molten AlSi...
Puga, Hélder; Barbosa, J.; Seabra, Eurico; Ribeiro, Carlos Silva; Prokic, MiodragThe effect of high intensity ultrasound on the degassing of AlSi9Cu3 alloy using the novelMMM(Multi-frequency Multimode Modulated) technology was studied. Different ultrasonic parameters (power and frequency), melt temperature and processing times were tested and their influence on the degassing efficiency evaluated. RPT (Reduced Pressure Test) was used to evaluate the hydrogen content in the alloys and the sam...
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