MICROSTRUCTURE AND PROPERTIES OF Al_2O_3sf/Al -1.5Mg COMPOSTITE MANUFACTURED BY EXTRUSION DIRECTLY FOLLOWING LIQUID INFILTRATION

摘要

The microstructure and properties of short alumina fiber reinforced Al-1.5Mg composite (Al_2O_3sf/Al-1.5Mg) manufactured by extrusion directly following liquid infiltration (EDFLI) were experimentally investigated. It was found that the microstructure of Al_2O_3sf/Al-1.5 Mg composite is characterized by a well-densified matrix, with fine recrystallized grains and free from microvoids and non-wetting defects, and quite uniformly and quasi unidirectionally distributed fibers maintaining adequate aspect ratios, which leads to a better strengthening effect. It was also found that the mechanical properties E, σ_(0.2), σ_b and the thermal expansion resistance of the composite simultaneously increase with the enhancement of the fiber volume fraction while the elongation δ is still maintained at a relative high level. Besides, the Al_2O_3sf/Al-1.5Mg composite possesses corrosion resistance equivalent to that of the Al-1.5Mg alloy.