Effect of original layer thicknesses on the interface bonding and mechanical properties of Ti[sbnd]Al laminate composites

Abstract

It is of great significance in high-temperature aeroengine applications for large-surface-area TiAl laminate composites to be fabricated into Ti-Al3Ti parts by plastic forming and subsequent vacuum hot pressing. Then the original layer thicknesses have an important influence on the interface bonding and mechanical properties of TiAl laminate composites, but only few reports about it have been published so far. In the present study, vacuum hot pressing was employed to fabricate TiAl laminate composites using Ti and Al foils of different thickness. The resulting interface bond and mechanical properties of TiAl laminate composites were then studied to determine the optimum sheet configuration and thickness. To further assess their formability and develop a forming limit diagram (FLD), 0.1/0.15 TiAl laminate composites were operated on bending and forming tests to provide guidance for subsequent plastic forming of complex geometries. The results indicated that hot pressed laminates composed of alternating 0.1 (Al) and 0.15 (Ti) mm thick sheets exhibited enhanced superior interface bonding and mechanical properties compared with 0.2/0.25 and 0.4/0.4 sheets. The 0.1/0.15 TiAl laminate composites had excellent bending characteristics and reasonable formability. Fabrication of a drawn cup further confirms the potential for hot pressed TiAl laminate composites to be fabricated into complex shapes.