Effects of interface roughness on the annealing behaviour of laminated Ti-Al composite deformed by hot rolling

Abstract

The preparation of the Ti-Al alloys based on intermetallic phases N Kosova, V Sachkov, I Kurzina et al. -Investigation of physical and mechanical properties of coatings based on intermetallics of the Ti-Al system obtained in acetylene environment from vacuum-arc discharge plasma E L Vardanyan, A Yu Nazarov, K N Ramazanov et al. Abstract. A laminated Ti-Al composite has been fabricated by hot compaction and hot rolling of alternate layers of commercial purity Ti and Al sheets with a thickness of 200 μm. The hot compaction temperature was 500˚C and in a following step the composite has been reduced 50% in thickness by hot rolling. The fully consolidated composite has been annealed at 300˚C and 500˚C for different length of time. As a result of the differences in crystal structure and mechanical properties between Ti and Al protrusions and retrusions formed at the interface. A heterogeneous interface has thereby been created. The heterogeneity affected the recovery kinetics of the aluminium phase which at 300˚C was faster near the interface than in the middle of the Al layer. This effect of a heterogeneous interface is of relevance when optimizing the thermomechanical processing of the composite to obtain high strength and formability for application.

Laminated Ti-Al composites: Processing, structure and strength

“…Since Ti and Al are strong and light, respectively, it is important to study laminated Ti-Al composites (LMCs) to fill a requirement of strong and light materials for automobile and aerospace industry. Hot-rolled laminated Ti-Al composites have been designed and fabricated in our previous study [26]. The interfaces of the hot-rolled laminated Ti-Al composites have been carefully characterized by SEM/EBSD, revealing that a rough interface creates heterogeneity, which affect the annealing behavior of the LMCs.…”

Revealing extraordinary tensile plasticity in layered Ti-Al metal composite

“…Finally, LMC was rolled to a total thickness reduction of 50% after 6 rolling passes and annealed at 500 °C for 10 minutes after each rolling pass. The details of rolling conditions have been mentioned elsewhere37.…”

Effect of Interface on Mechanical Properties of Ti/Al/Mg/Al/Ti Laminated Composites

“…Ma et al 28 and Xia et al 31 also didn't find intermetallic phases at Ti/Al peeling surface of rolled and explosive welded Ti/Al layered composites because of the shorter reaction time. While Du et al 32 detected TiAl 3 phase with a DO22 structure at Ti/Al interface fabricated by vacuum hot-pressing and hot-rolled. Also, Yu et al 21 proved that TiAl 3 was the only phase that could form and grow at Ti/Al interface after annealing at 873 K for 6 h for as-rolled Al/Ti/Al.…”

“…Also, the difference in thermal conductivity between layers causes a local temperature increase. During cooling after deformation, due to different cooling rate, regions with severe thermal stresses are generated, which results in thermal unmatched dislocations at the interface 32 . All above factors lead to high dislocation density at the interface, so dislocation strengthening theory can explain this strengthening behavior.…”