Modification of the mechanical properties of Ti/Ta multilayer composites with heterogeneous lamella structure

Multilayer composites are promising to improve the comprehensive mechanical properties of conventional metals. In this study, a series of Ti/Ta multilayer composites with different thickness ratio between titanium layer and tantalum layer are prepared. The relationship between microstructure and mechanical properties of these Ti/Ta multilayer composites is investigated. It has been found that heterogeneous lamella structure, including alpha + beta titanium layer, pure beta-titanium layer ana tantalum layer, is developed in these composites. The volume fraction of alpha + beta titanium layer and tantalum layer decreases and the volume fraction of beta-titanium increases with the increase of bonding temperature. The composites bonded at 1300 degrees C has got the best comprehensive mechanical properties. Furthermore, the mechanical properties of the composites can be modified by adjusting the thickness ratio between titanium layer and tantalum layer. The mechanical properties of Ti/Ta30 multilayer composites are much better than that of Ti/Ta100 multilayer composites. The fracture morphology of the Ti/Ta multilayer composites prepared at different bonding temperatures are similar. However, the fracture morphology of tantalum layer and titanium layer are different. And a fracture mode is proposed.