A Study of the Method of Manufacturing Bimaterial Composite Parts through Semisolid Metal Processing

This work evaluated the method of manufacturing bimaterial composite parts by semisolid metal processing (SSP) through strain-induced melt-activated thixo-forging. Sn-15 pct Pb and Pb-30 pct Sn semisolid alloys were chosen as model alloys. Bimetal composite parts were manufactured successfully by forging the semisolid alloys into the same die simultaneously. Optical photography, scanning electron microscopy, energy dispersive X-ray spectroscopy, and Vickers hardness were employed to characterize the samples. The results showed that the composite semisolid fluid flowed in a laminar way. Globular primary grains in the two semisolid alloys maintained their respective geometry and constitutions. The mixture of two liquid phases was limited in a thin layer beneath the interface between the two semisolid alloys. The absence of an oxide-enriched layer at the interface suggests that the oxide skins of the feedstock were torn during the processing, leading to the formation of metallurgical bonding at the composite interface. This work showed that SSP is a promising technology for bimaterial/multimaterial composite manufacturing. The bimaterial composite parts achieved by SSP have a good composite interface and well-located material distribution.