Effect of Polygonal Rotor Process on Solidification Structure of Lead-Free Bismuth Bronze
Semi-solid slurry with fine solid granules for rheocasting was made from lead-free bismuth bronze by passing the low-superheat melt through an opening between a rotating regular octagonal rotor and a circumscribed chill block. We mainly investigated the effect of rotational speed on the structure of a solidified small ingot. The ingot structures changed from the dendrite of rotor-free condition to the rosette at the rotational speed of 50rpm and to the granular with a mean grain size of about 50m at higher than100 rpm. If the slurry made at 100rpm was rheocast to a disk shape by the use of a high pressure casting machine, the disk had almost uniform granular structures from the center to the edge regions.
Jian-Feng Nie and Allan Morton
T. Kose et al., "Effect of Polygonal Rotor Process on Solidification Structure of Lead-Free Bismuth Bronze", Materials Science Forum, Vols. 654-656, pp. 1389-1392, 2010