Effect of interfacial reaction layers on crack propagation behavior of Ti/Al layered metal composites in uniaxial tensile test from the perspective of local strain

This study investigates the effect of the interfacial reaction layer on the crack propagation behavior of Ti/Al layered metal composites (LMCs) under uniaxial tensile testing. Ti/Al and Ti/TiAl₃/Al LMCs were fabricated using vacuum hot-pressing. In-situ tensile tests, coupled with digital image correlation methods, were conducted to analyze crack propagation behavior from the perspective of local strain. These results show that the fracture elongation of LMCs decreases significantly with the presence of an interfacial reaction layer. Crack propagation shifts from following the layer interface to propagating perpendicularly to it. At low-tensile strain levels, microcracking occurs within the interfacial reaction layer. However, the adjacent ductile layers effectively suppress the instability of these microcracks. During tension deformation, the stress fields at the crack-tip in the neighboring interfacial reaction layers bridge together, forming stress-concentrated bands, that cause significant strain localization. More importantly, the accelerated accumulation of dislocation in the strain-localized regions depletes the work-hardening capacity, thereby promoting crack propagation along the localized path. Therefore, inhibiting the formation of the interfacial reaction layer in LMCs can enhance strain delocalization and improve fracture elongation.