Resumen de Thermomechanical behavior of Al-Cu-Si commercial alloy modified with rare earths
J. Camarillo Cisneros, R. Pérez Bustamante, R. Martínez Sánchez
Microstructural and mechanical effects were studied on automotive-grade 319 aluminum alloy after cerium/lanthanum rare earth additions at room and hot working conditions. Cerium/lanthanum additions formed micrometric phases in AA319, which were stable under room and hot working conditions. In comparison with reference alloy, Ce/La doped alloys reduced the eutectic-Si up to 85%. The effect of the Ce/La addition produced an increase in hardness and UTS under room temperature while improved mechanical performance in high-temperature working conditions. These improvements were attained to the presence of well-dispersed Ce/La micrometric needles, and the amount increase of θ’-phase (Al_(2)Cu) across the aluminum matrix. The θ’ interfered directly with crack diffusion in the solid in two crystallographic directions. Additionally, it was observed through transmission electron microscopy, that Ce/La presence altered the precipitation kinetics in the formation of the coherent θ from the θ’.
