Numerical Simulations And Preparation Of Al/Mg/Al Explosively Welded Composite Plate

Magnesium has the advantages of light-weight,high-strength and abundant resources,thus is used in aerospace,automotive and other fields.However,lack of corrosion resistance seriously restricts the wide application of magnesium and magnesium alloys.Adopt the method of surface cladding aluminum,two layers of 6061 aluminum alloy materials in on both sides of AZ31 B magnesium alloy,the composite plate material can not only possess the characteristics of high toughness and corrosion resistance of aluminum alloy,but also improve the surface performance and comprehensive mechanical properties of magnesium alloy materials.In this paper,providing the explosive welding method to preparing Al/Mg/Al composite plates,this paper also research the weldability window,welding processes and generation of wavy morphology.The practical explosive welding has the characteristics of instantaneous and dangerous,it is hardly to observe the welding processes.Thus it is necessary to research the welding processes by numerical simulations.In This paper,the weldability window of Al/Mg/Al explosive welding is calculated by means of ANSYS finite element numerical simulations;The numerical simulation tests also describe the processes and the bonding mechanism of Al/Mg/Al explosivewelding;Through the analysis of numerical simulations for the composite plate interface,The formation processes of wavy morphology and the influence of the material performance on interface morphology can be described by simulations;According to the results of simulations,this paper prepare Al/Mg/Al composite plates successfully by practical explosive welding.The theory of stress wave and numerical simulations can be used to research the method of three layers explosive welding in one stage.By the research of weldability window for explosive welding,this paper select the minimum collision velocity,minimum thickness of flyer plate and minimum collision angle as the lower limit;It also select the melting collision velocity and maximum flyer angle as the upper limit.The value of weldability limits are solved by numerical simulations.Thus this paper build a practical weldability window for Al/Mg/Al explosive welding successfully.The processes of Al/Mg/Al explosive welding in simulations indicate that wavy morphology and jet flow are appeared at interface.The velocity and pressure of material at the collision point reach the maximum.The peak pressure of Mg alloys and Al alloys can reach 34 GPa and 48 GPa,which are far more than the yield strength of material itself;The peak value of effective plastic strain of Mg alloys and Al alloys are up to 510% and 250%;The interface of composite plates have a thin layer of melting zone,The peak value of temperature of Mg alloys and Al alloys are up to 1200 K and 1000 K,which are far more than the melting points of material itself.Thus the results ofsimulations provide theoretical evidence for successful plastic joining at Al/Mg interface of Al/Mg/Al composite plates.According to the results of simulations for Al/Mg/Al explosive welding processes,This paper research and describe the generation processes and the effect of blasting impact load of wavy morphology in explosive welding by simulations.Illustrating the effect factors of formation for wavy interface in explosive welding: The density ratio and strength ratio of materials in base plate and flyer plate would influence the morphology of interface.The materials of composite plates decide the jet flow generate or not.The jet flow of flyer plate is an essential factor for the generation of complete wavy morphology.If the flyer plate can't generate jet flow,the jet flow of base plate can only generate "quasi-wavy" or "semi-wavy" at interface.This paper prepare Al/Mg/Al composite plates by explosive welding in one stage successfully.Welding parameters are selected by Al/Mg/Al weldability window and the parameters of numerical simulations.Analysising the interface morphology of Al/Mg/Al alloy composite plates: The wavy morphology appeared at the two sides interface of composite plates clearly;The stress wave have influenced the Al/Mg/Al explosive welding and cause reflecting fracture on composite plates.This paper research the reasons of generation for reflecting fracture by theory of stress wave and demonstrate by numerical simulations.