Laminated metal composites have broad development prospects and have been applied in many fields, such as aerospace, equipment manufacturing, and chemical industries [1
]. Explosive welding (EXW) is one of the effective technologies to manufacture laminated metal composites with controllable thermal conductivity, ideal mechanical properties, better erosion resistance, and obvious economic benefits. Over 260 various similar and dissimilar materials can be fabricated by using explosive welding techniques [1
Explosively driven impact welding belongs to the field of multidisciplinary research, which relates to complex chemical reactions (e.g., explosive explosion), physical processes (e.g., hypervelocity impact), and metallurgical processes (e.g., welding of metals) [5
]. Due to the fact that these phenomena mentioned above complete in a very short duration under high temperature and high pressure, the transient forming process is difficult to be observed and measured in an experiment, and the time history seems difficult to understand as well.
With the development of computer software and hardware technologies, the finite element method (FEM) has been applied to study the explosive/impact welding in recent works. Nassiri and Kinsey [6
] studied the process of the high-velocity impact welding by using SPH (smoothed particle hydrodynamics) and ALE (arbitrary Lagrangian-Eulerian) methods, respectively. Simulation results of both of these methods, such as interfacial waves, the shear stress, and velocity in the vicinity of the collision point were consistent. However, the phenomenon of jetting was only reproduced in the simulation by using the SPH method. Wang et al. [7
] applied the SPH method to study the mechanisms and the physical phenomenon of the explosion welding of titanium and its alloys. In their simulations, the changing physical processes involving shear stress and effective plastic strain of materials were clearly shown. Nassiri et al. [8
] predicted the weldability window of the high-velocity impact welding by using ALE finite element method. An experiment was conducted to validate the FEA (finite element analysis) model and the weldability window. The results of the experiments and numerical simulations were completely consistent. Aizawa et al. [9
] investigated the chemical composition, the intermediate layers at explosive-welded Al/Fe joint interfaces by experimental and numerical analyses. The temperature distribution near the interface shown by the SPH simulation explained the formation mechanism of two types of intermetallic compound. Abe [10
] used a two-dimensional finite difference scheme to research the mechanism of the wavy interface generation in explosive welding. The computational results agreed very well with the experimental results. Yuan et al. [11
] studied the process of 6061 Al/AZ31B explosive welding using SPH. The wavy interface and the phenomenon of jetting were reproduced, but the detailed mechanism of the interface wavy structure was not illustrated. Grignon et al. [12
] studied the conditions for a straight, smooth weld formation in the explosive welding of 6061 T0 and 6061 T0. In their study, the numerical simulation and the analytical calculations were used to confirm the experimental results and explain the difficulties met with obtaining a continuous straight interface. The numerical simulation results demonstrated that the change in the collision angle was directly responsible for the change in the interface morphology from wavy to smooth. Mousavi and Al-Hassani [5
] used an Euler processor to model the explosive/impact welding process, but the historical process data of explosive welding was difficult to be understood using Euler computation. Carrino et al. [13
] studied the effect of workpiece thickness in superplastic forming/diffusion bonding of a titanium alloy by using finite element analysis.
However, the numerical models in aforementioned research simplified the actual explosive welding process, and ignored the explosion of explosives and the acceleration of the flyer plate [6
]. Basing on the Gurney formula or Richter formula, they regarded the explosive welding process as high-velocity impact welding (HVIW). Specifically, the simulation was performed by imposing a constant impact velocity for the flier plate (V) and giving an initial angle (β) between the flier and base plates as the initial conditions, as shown in Figure 1
. In order to reproduce the actual physical process of explosive welding, the explosion of explosives and the acceleration of the flyer plate should be also considered.
Ti/Al bimetal composites have been widely used in the industry [1
]. There are many reports concerning the EXW of Ti and Al. Most previous experimental studies focused on the microstructure and mechanical characteristics of Ti/Al layered materials [3
]. However, the forming process of explosive welding of Ti/Al is still not clear. Few studied the explosive welding process of Ti/Al layered materials by simulation.
The present work is motived by the research involving numerical simulation of a Ti/Al bimetal composite fabricated by explosive welding. The numerical model that is closer to reality is applied to study the explosive welding of the Ti/Al composite plate. The characteristic phenomena in the Ti/Al explosive welding process are reproduced and some physical parameters, such as collision velocity, pressure, effective plastic strain, and shear stress, are also discussed. The interfacial morphology of the Ti/Al composite in the numerical simulations was compared with an experimental test. The numerical simulations provide an efficient way to make us study the inherent physics of explosive welding. This paper may provide a new contribution in the field of Ti/Al laminated composite manufacturing.