This paper presents a systematic study of structure and mechanical behavior of Ti/Fe explosive-bonded interfaces. The transient fluid-like behavior at the bonding zone is simulated using Smoothed Particle Hydrodynamic (SPH) numerical method. The interface is featured by a wave structure, resulted from heavy plastic deformation during the explosive welding. Melted zone resulted from the trapped jetting is surrounded by strongly deformed bulk materials. Fe2Ti intermetallic compounds with a mixture of FeTi+Fe phases are observed in the melted zone. A reaction layer (~700nm) consisted of nano-sized FeTi grains is formed at Ti/Fe material boundary. Nanoindentation tests and fracture observation confirm the brittle nature of Fe-Ti intermetallics formed in the explosive-bonded joint. Extremely temperature accumulated near the interface leads to recovery and recrystallization in deformed grains, which can accommodate relatively large strain near the interface.

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Experimental and numerical investigation of microstructure and mechanical behavior of titanium/steel interfaces prepared by explosive welding

This paper presents a systematic study of structure and mechanical behavior of Ti/Fe explosive-bonded interfaces. The transient fluid-like behavior at the bonding zone is simulated using Smoothed Particle Hydrodynamic (SPH) numerical method. The interface is featured by a wave structure, resulted from heavy plastic deformation during the explosive welding. Melted zone resulted from the trapped jetting is surrounded by strongly deformed bulk materials. Fe 2 Ti intermetallic compounds with a mixture of FeTi+Fe phases are observed in the melted zone. A reaction layer (~700nm) consisted of nano-sized FeTi grains is formed at Ti/Fe material boundary. 

Nanoindentation tests and fracture observation confirm the brittle nature of Fe-Ti intermetallics formed in the explosive-bonded joint. Extremely temperature accumulated near the interface leads to recovery and recrystallization in deformed grains, which can accommodate relatively large strain near the interface.

This paper presented a systematic study of microstructure and mechanical properties of Cu/Fe explosive-bonded interfaces. The periodic wavy bonding structure with both vortex region and solid-solid bonding region was embedded in the interface. Typical annealing twin structures were observed in the texture and orientation analysis of Cu matrix. The ASBs filled with some much smaller size equiaxed grains and orientation variations in different areas were found in the Fe matrix. The transition layer consisted of nano-sized grains of 60 nm was formed between the copper and steel plate. The microindentation results showed that the hardness of the interface (330.9 MPa) and deformation area (Cu 100 HV and Fe 286.8 HV) was higher than the matrix regions. The higher hardness of the transition layer (15.707 GPa) determined by nanoindentation analysis was explained by the existence of nanocrystallines in this zone. The induced tensile tests showed that the cracks didn’t extent along the interface wave structure but inside the copper matrix, reflecting the high quality of the bonding.

Microstructure and mechanical properties investigations of copper-steel composite fabricated by explosive welding

Microstructure evolution and mechanical properties of an AA6061/AZ31B alloy plate fabricated by explosive welding

The ability to combine multiple materials (MM) into a single component to expand its range of functional properties is of tremendous value to the ceaseless optimization of engineering systems. Although fusion and solid-state joining techniques have been typically used to join dissimilar metals, additive manufacturing (AM) has the potential to produce MM parts with a complex spatial distribution of materials and properties that is otherwise unachievable. In this work, the selective laser melting (SLM) process was used to manufacture MM parts which feature steep material transitions from 316L stainless steel (SS) to Ti-6Al-4V (TiA) through an interlayer of HOVADUR® K220 copper–alloy (CuA). The microstructure in both the CuA/SS and TiA/CuA interfaces were examined in detail and the latter was found to be the critical interface as it contained three detrimental phases (i.e. L21 ordered phase, amorphous phase, and Ti2Cu) which limit the mechanical strength of the overall MM part. By making use of the non-homogeneity within the melt pool and limiting the laser energy input, the relatively tougher interfacial α′-Ti phase can be increased at the expense of other brittle phases, forming what is essentially a composite structure at the TiA/CuA interface. During tensile testing, the interfacial α′-Ti phase is capable of deflecting cracks from the relatively brittle TiA/CuA interface towards the ductile CuA interlayer and an overall tensile strength in excess of 500 MPa can be obtained. This method of introducing an interfacial composite structure to improve MM bonding is envisioned to be applicable for the SLM of other metallic combinations as well.

Min Zhang

Papers

Experimental and numerical investigation of microstructure and mechanical behavior of titanium/steel interfaces prepared by explosive welding

Experimental and numerical investigation of microstructure and mechanical behavior of titanium/steel interfaces prepared by explosive welding

Influence of vanadium filler on the properties of titanium and steel TIG welded joints

Joining of CP-Ti/Q345 sheets by Cu-based filler metal and effect on interface