Microstructure And Properties Of Magnesium-Aluminum Composite Board Prepared Through Explosive Welding

Magnesium alloys are a kind of important light alloys,which are mainly used in aviation and automotive fields.However,magnesium alloys have been limited in their applications due to their poor corrosion resistance,high surface notch sensitivity and low toughness.AZ31B magnesium alloy has low density,good shock absorption and heat dissipation.In order to expand its application range,the magnesium-aluminum compositeboards can be prepared by coating the 5052 rust-proof aluminum alloy,so that the magnesium-aluminum composite board gets good corrosion resistance and better toughness.In this paper,magnesium-aluminum composite boards are prepared by explosive welding.Ultrasonic flaw detection was used to detect the combination of explosive composite boards,and the unbonded areas were cut off.The remaining composite boardswere analyzed by OM,XRD,SEM and EDS.The interface morphology,diffusion layer thickness and phase composition of the composite boards were studied.Then tensile,bending,shearing,impact and hardness mechanical properties of the explosive and annealed composite boards were tested.The magnesium-aluminum explosive composite boards were prepared under 25+5?explosive thickness is 25mm,space between base plate and flyer plate is 5mm?,20+5 and18+3 three sets of explosion parameters.The results showed that the interface of the composite board is a wave interface.As the explosive energy decreases,that is,when the explosion welding parameters are 25+5,20+5,and 18+3,the wavelength and waveheight of the interface waveform decrease gradually.The wavelength decreases from 800?m to 150?m and the waveheight decreases from 250?m to 25?m.The thickness of the interface diffusion layer of the composite board is reduced from 9?m to 1?m;The intermetallic compounds Al₃Mg₂ and Mg₁₇Al₁₂ are formed at the interface of the composite board,and the gap between the magnesium plate and the aluminum plate is reduced from 7?m thick to 0?m;The mechanical properties test shows that the interface shear strength of the magnesium-aluminum composite board prepared under 18+3 parameter increases by 15.3%compared with that prepared under 25+5 parameters.The magnesium-aluminum composite boards prepared under the parameters of 25+5were annealed at 300°C,350°C and 400°C for 1 h respectively.The results showed that the gap at the interface disappears and the thickness of the diffusion layer increases significantly after annealing;The interface shear strength after annealing at 300°C were higher than annealed at 350°C and 400°C.Compared with the explosive composite board,the reduction of area of the composite plate after annealing at 300°C increases by 236.4%,the elongation after fracture increases by 421.9%,and the impact absorption energy increases by 10.3%.Comparing the properties of the explosive composite boards which were prepared by using 25+5,20+5,18+3 three sets of explosion parameters after annealing at 300°C for 1 h,it was found that the interface shear strength of the 18+3 magnesium-aluminum composite board after annealing was the highest,reaching 75.28MPa.The 18+3 magnesium-aluminum explosive composite board after annealing at 300°C for 1 h was rolled.After the first pass,the magnesium side of the composite board was not cracked,but the interface of the composite board was delaminated.Because the deformation of the magnesium side and the aluminum side of the composite board during the rolling process is not coordinated,the traction at the interface exceeds the interface shear strength of the composite boardand delamination occurs.