Abstract
Magnesium–magnesium bimetal composites were prepared by insert molding method in this study. To achieve good metallurgical bonding between AZ31 insert and AZ91 matrix, different fabrication process parameters such as volume ratio (V91:V31 = 1:1 or 2:1) and insert temperature (650 °C, 675 °C, 700 °C), were tested. It was shown that high-quality metallurgical interface bonding could be achieved when the volume ratio (VAZ91:VAZ31) is 2:1 and the insert temperature is 675 °C. The average interface tensile strength of the bimetal fabricated by insert molding could approach 100 MPa, which is close to the reported as-cast AZ91 tensile strength value. The fracture analysis also indicated that during the tensile test of bimetal composite, the crack initiation began in the weak zone of casting AZ91 alloy. Moreover, the bonding mechanism of the interface were also investigated in details combined the temperature measurement experiments and the corresponding numerical simulation work in this study. The results presented in this paper indicated that the insert molding method is a promising and effective approach to develop advanced Mg/Mg bimetal composites for widening the application of magnesium alloys.
