Abstract
Cast aluminum alloys with a wide range of spherical α size were prepared utilizing the inclined cooling plate technique. In addition to the change in the α size, the sizes of grain and Si and intermetallic compound particles were significantly reduced and spheroidized by the introduction of semi-solid process. Although almost all the mechanical properties became highest in rheocast material with a α size of 38 μm, the increment was merly 10 % compared to squeeze cast material. Although differences in damage accumulation behavior during tensile loading was quantified by in-situ studies, there did not seem to be discernible effects on fatigue properties. The less than expected improvement was not attributed to differences in grain structure according to the quantitative investigation on microrientation angles between neighboring grains utilizing the SEM-EBSP technique. Relatively modest improvement in comparison to literature seems to be rational, considering that the rheocast process changes only the spatial distribution pattern of the Si particles.
