Horizontal twin-roll casting technology was successfully introduced to produce high-performance copper/aluminum (Cu/Al) laminated composites. The interface morphology, electrical properties and peeling strength after different annealing and cold rolling processes were investigated and contrasted with Cu/Al clad plates fabricated by conventional methods. The results show that sound metallurgical bonding between the copper and aluminum matrix can be attained after the horizontal twin-roll casting processes and Al 2 Cu is the only intermetallics at the interfacial region, the thickness of interfacial interlayer is about 0.7 mm. The peeling strength is 31.4 N/mm and can be further increased to 37.1 N/mm after annealing at 250 8C. However, higher temperature like 400 8C will cause the excessive growth of intermetallics so that peeling strength sharply decreases to 9.2 N/mm. Electrical conductivity of the clad plate is 51 MS/m. At the same electrical current intensity, the temperature-rise of the composite plate is between the pure copper plate and the aluminum plate, and closer to the copper plate. All of the properties are outstanding than that of Cu/Al clad plate fabricated by conventional methods.

A study of the formation of gouging pits in Mn7CrZ steel zinder impact abrasizie wear conditions was conducted using theories of elastic impact and contact, analysis of photoelasticity, and scanning electron microscopy (SEM). The results show that the maximum shear stress occurs at z = 0.48~1, and this initiates a crack; the crack propagates at an angle of 45" from the horizontal; and the gouging pit is conical. The SEM observations are in agreement with the theoretical calculations.

A mathematical model has been developed and validated for the horizontal twin-roll casting of copper/aluminum clad sheet. The influences of the heat transfer coefficient for copper/roll interface, casting speed and clad sheet thickness on the sump depth and temperature distribution of the copper/aluminum interface were studied. The interface morphologies and chemical compositions of the intermetallic compound layers were analyzed. The results showed the sump depth decreased with the increase of heat transfer coefficient for copper/roll interface and moved to the outlet with the increase of the casting speed. Casting speed was linear with the sump depth ratio to set-back distance on the centerline for different clad sheet thicknesses. The thickness of the intermetallic compound layer increased with the increase of the clad sheet thickness. Only Al 2 Cu layer formed on the copper/aluminum interface with clad sheet thickness of 6 mm, and the second layer of Al 4 Cu 9 formed near the copper side with the increase of the thickness.