An investigation on bonding mechanism and mechanical properties of Al/Ti compound materials prepared by insert moulding

Abstract

Al/Ti metallic composites prepared by insert moulding are attracting more attention now because of their low production costs, low energy consumption, simple production procedure and high interface bonding strength. However, the insert moulding of pure Al and pure Ti has not been reported so far though it can be considered as a fundamental in studying Ti-alloy/Al-alloy interface bonding. Therefore, the insert moulding of pure Al and pure Ti is intended in this paper and the corresponding microstructure, elements distribution and mechanical properties of the interface are also analyzed. As a result, a good metallurgical bonding can be achieved at the interface of Al and Ti, which is mainly comprised of intermetallic compounds TiAl2 and TiAl3 formed in the transition zone around Ti insert and Al matrix, respectively, depending on different heat treatment parameters and cooling conditions. It is shown that the hardness of the interface layer varies with the types of interface sublayers. For the compact sublayer, the hardness is higher than those of both base metals (Al and Ti) with the maximum value reaching HV520. However, the hardness of the granular interface sublayer depends on the proportion of the intermetallic compounds and aluminum matrix. The average shear strength of the interface layer could reach about 60MPa, which is higher than that of the aluminum matrix (43MPa) tested in this experiment. The result also shows that shear crack initiates at bottom face of the specimen (adjacent to locator) in the aluminum matrix nearby the interface.