한국주조공학회

Effects of the zinc coating layer thickness on cast-bonding characteristics of layered type steel/aluminum bimetals, fabricated using high-pressure die casting process, were investigated. The interfacial bonding strength showed a tendency to decrease sharply with an increment of the coating layer thickness. When galvanized steels with a 2.5 μm coating thickness were used as inserts, submicrometer thick Al-Fe-Si intermetallic compound layers were uniformly formed at the joint interface, resulting in ductile fracture behavior and a high interfacial bonding strength of 130 MPa. On the other hand, when galvanized steels with a coating thickness of 5 μm or more were used, or in regions where the molten metal injection direction branched vertically, the interfacial bonding reaction did not occur sufficiently. In addition, undesirable solidification structures, including coarse primary Si phases and Zn-rich segregated cell boundaries, were evolved in the aluminum matrix near the joint interface.

Aluminum alloys, Galvanized steels, Bimetals, High-pressure die casting and Interfacial bonding strength.