Thixoforming A356 Aluminum Bipolar Plates at High Solid Fractions

摘要: Thixoforming investigations have been developed primarily for the manufacturing of bulk components, and current knowledge is very limited with respect to fabrication thin cross sections alloys. We studied effectiveness thixoforming process A356 aluminum alloy bipolar plates microchannels on both sides. Feedstock semisolid slurries, different solid contents ~55, 50, 45 pct, were prepared at 858 K, 863 868 K (585 °C, 590 595 °C), respectively, used thixoform 1.20-mm-thick plates. The microstructures thixoformed consisted (i) large primary α-Al globular grains, (ii) a quenched liquid phase, (iii) fine secondary particles. fraction size grains decreased, became more spherical increasing temperature. It seemed that these changes in microstructural features led reduction agglomeration interaction among surrounded by matrix during thixoforming. This enabled slurry effectively flow fill sharp corners (such as microchannels) die cavity higher temperatures. (595 consequently, exhibited highest dimensional stability fewest internal defects. surrounding solidified inside after Either phase was instantly or particles formed cavity. latter increased surface hardness measured, values correlated