EFEITO DO TRATAMENTO TERMICO T6 NO COMPORTAMENTO MECÂNICO DA LIGA Al3Si2,5Cu TIXOJORJADA

Ano: 2019

Instituições de ensino: Instituto Federal de Educação, Ciência e Tecnologia de São Paulo, Universidade Estadual de Campinas, Universidade Estadual de Campinas

Idioma: Portugues

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Resumo

This work presents the comparative results of the mechanical properties of microhardness, tensile strength and fatigue strength of aluminum alloy Al-3wt%Si-2.5wt Cu under the conditions, as-cast, thixoforged, (with controlled partial melting), and subsequent heat treatment T6. For this, the alloy under study was manufactured using techniques that allowed the refining and globularization of its microstructure to facilitate the thixoforging process, through the use of grain refining with the imposition of electromagnetic stirring during solidification. The subsequent thixoforging was performed in a 12 ton pneumatic press after reheating the material at temperature of 616 °C with maintenance at this stage for about 30 s using an inductive furnace. This temperature corresponds to the liquid fraction of about 55% according to Thermo-Calc® thermodynamic simulation software. The thixoforged part were analyzed in microstructural and mechanical terms in the conditions as thixoforged and after heat treatment of solubilization and artificial aging T6. The microhardness was practically doubled after T6 from 59HV to 127HV, the tensile strength in terms of yield stress (sy) and rupture limit (sr) goes from 114 to 257 and 171 to 294 MPa respectively with decreasingo elongation (?) from 3.4 to 2.8. The fatigue limit (Se) increases from 64 to 78 MPa. It was evidenced the importance of T6 for the improvement of the mechanical properties of thixoforged parts in this material.

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