Manufacturing and property evaluation of A356/Saffil and hybrid A356/(Saffil + SiC_p) composites fabricated via melt infiltration technique

摘要

The incorporation of alumina short fibers (SAFFIL) into aluminum alloys increases significantly the modulus and strength of the alloy. Melt infiltration techniques have been emerged as an attractive fabrication route to manufacture high-volume-fraction high-performance net-shape alumina short fiber (SAFFIL) reinforced aluminum matrix composites. The production of porous SAFFIL preforms and hybrid SAFFIL +SiC_p preforms and the composite there from using squeeze casting technique have been the main steps of this research. The preforms were produced by mixing SAFFIL fibers (and SiC_p) with colloidal silica binder, and different surfactants and deflocculants followed by spontaneous settlement of reinforcement(s) from the homogenous slurry, natural drying, heating and final strengthening. The effect of different process parameters on the properties of these preforms will be discussed in this paper. The influence of different superheats above the liquidus of the infiltrating A356 alloy on the infiltration profile and depth of infiltration of the A356 aluminum alloy into the preforms and properties of the A356/SAFFIL and hybrid A356/(SAFFIL+ SiC_P) composites were also determined.