| Explosive welding materials with the excellent comprehensive performance have been widely applied in Engineering. Researches about explosive welding so far have focused mostly on the formation of the welding interface and integrate compound of welding materials, and researches about the service behavior and performance are relatively weak. The studies of explosive welding interface tensile shear behavior which determine and evaluate the welding interface performance, and they have an important significance. In this article shear experiment of 2024 Al-Al explosive welding composite material was carried out(without heat-treated) to study the shear damage behavior of explosive welding interface. Observing the fracture interface, found that specimen welding interface shear strength is decreasing with loading rate rising, and the fracture characteristics changed from brittle to ductile, it shows negative strain-rate effect. Furthermore, This paper use fractal theory to characterize the specimens shear fracture interface, and try to establish the relationship between fracture interface shear strength and its fracture profile fractal dimension value and multifractal spectrum. In addition, numerical simulation based on the experimental results is carried out to reveal the mechanism of shear failure of the specimens. This article consists of a series of researches to get the following conclusions:1. The results suggest that the shear strength decreased by the increasing of strain rate, and the fracture surface morphology and its profile fractal dimension revealed the reasons of the fracture interface Shear strength changed. Besides, the differences of vertical and horizontal direction between two endpoints of the multifractal spectrum reflect the stereoscopic vision of the surface, and they have positive relationship with shear strength too.2. Because the shear specimens are made by explosive welding materials, There are work-hardening in the welding interface. In the shear experiments the work-hardening soon achieve threshold and no longer increase, while softening of the shear interface grows with load increasing, eventually lead to the welding interface shear strength decreasing and fracture ductile characteristics increasing. The welding interface shear strength not changed directly with strain rate, but the softening of the material caused by strain rate, it ultimately affect the shear strength of the material and the evolution of the brittle and ductile fracture.3. Contrasting the numerical simulation results of 2024 Al and explosive welding materials, found that the 2024 Al specimen has tensile fracture morphology and the change of shear layer stress is relatively simple, the explosive welding specimen owns shear fracture morphology and the variation of shear layer stress has a great fluctuation characteristics. It suggests that welding interface changes the cracking mechanism of specimen. |
PDF Full Text Request