Research On Explosive Composite Materials With High Utilization Rate And Its Impact Damage Characteristics

In order to improve the utilization rate of materials and reduce the amount of welding charge,a study on high utilization rate explosive composite materials and their impact damage characteristics was proposed.The experiment used an emulsified matrix as the basis,hollow glass microspheres as sensitizer and diluent,and honeycomb aluminum plate as explosive frame.double-layer honeycomb structure explosive with a total thickness of 8mm was prepared for copper/steel explosive welding research.The explosive welding of 1050 aluminum plate and Q235 steel plate was studied by combining numerical simulation and experiment.SEM,EDS and microhardness tester were used to characterize and analyze the microstructure of the interface of aluminum-steel composite plate,and the forming mechanism was studied by ANSYS/AUTODYN software.The explosive welding of 200μm titanium foil and steel plate was studied by adding a protective layer of salt.The microscopic morphology of the interface was observed by metallographic microscope,scanning electron microscope and energy dispersive spectrometer,and the forming mechanism was studied by numerical simulation software.The brittleness of molybdenum foil and copper explosive welding was studied by means of microscopic observation and elemental and hardness analysis.Through the analysis of microstructure and element changes,it could be analyzed,explain and propose solutions of the formation of microscopic cracks.The following conclusions can be drawn:In order to improve the utilization rate of explosive explosion energy and reduce the amount of welding charge,a self-contained structural charge was proposed to carry out explosive welding research.T2 copper and Q345 steel were used as fly layer and base layer respectively to obtain copper/steel explosion welding window by theoretical calculation.Experimental research on copper/steel explosive welding was carried out by using double-layer honeycomb structure explosives as welding energy.Explosive welding with self-contained structural explosives had good bonding properties of copper/steel clad plates.Compared with the detonation velocity of 2505m s^-1 and 3512m s^-1 single-layer charge structure explosives,the copper/steel explosion welding of double-layer honeycomb explosives could save 54.4%and 31.4%of the charge respectively.As the collision point moves,the copper/steel composite interface changed from a flat bond to a wave bond.SEM and EDS tests showed that intermolecular diffusion of wide range was difficult to occur at the composite interface,but there were copper/steel melting blocks.The microhardness showed that the collision at the interface was more severe,so the hardness had a higher increase,and the hardness gradually stabilized with the increase of the distance.The average maximum tensile force of the copper/steel composite plate was22.5KN,and the shear strength was 237.0MPa.Plastic deformation occurred on the copper side of the composite plate during tensile shear failure.The greater the distance from the bonding surface,the greater the degree of plastic deformation.Work hardening caused by plastic deformation will lead to an increase in the hardness of the composite plate.In order to reduce the usage of titanium/steel composite rare metal titanium and explore the formation mechanism of its explosive welding interface,explosive welding of 200μm thick TA1 titanium foil and Q235 steel plate was carried out.Scanning electron microscopy and metallographic microscopy were used to analyze the microscopic morphology of the interface,and ANSYS/AUTODYN was used to simulate the formation process of the interface wave and the melting block in the vortex.The test results showed that the salt pressure transfer layer could play a good buffer role in the collision between the fly plate and the base plate in the explosive welding of the foil plate.The joint surface formed a regular waveform,and no holes,cracks and other defects were observed in it.this could indicate that the titanium foil/steel composite plate had good welding quality.It was observed that there was a molten layer at the interface and a molten block in the vortex,in which there are intermetallic compounds such as Fe Ti and Fe₂Ti in the molten block,and there might be a small amount of metal oxides.In order to reduce the generation of brittle intermetallic compounds,an electroless copper layer was added to carry out the study of explosive welding of aluminum-steel.Copper was plated on the surface of the steel plate,and the copper layer was used to replace part of the steel to melt,so as to improve the welding effect of the composite plate.The influence of copper on the interface of aluminum-steel explosively welded clad plate was studied by combining numerical simulation and experiment.The result shows:Copper with a low melting point and low hardness could be used to replace part of the Fe melting,and explosive welding of 1060 Al and Q235 steel could be realized with parameters outside the explosive welding window.High atomic content of copper in the melting zone and in the vortex,it caused the hardness of the melted area to drop to between the hardness of the fly and base materials,it could avoid areas of excessive hardness at the welding interface of the clad plate.This work was for reducing the hardness of the melting zone,improving the toughness of the welding interface of the composite plate,and preventing the formation of cracks.The collision energy was more converted into the internal energy of the copper layer,crash melting layers of copper will consume less energy than steel,this could provide a new idea for saving explosive welding charge.In order to explore the impact damage performance of composite materials,the explosive welding of molybdenum foil and copper was studied.Through the analysis of microstructure and elements,ideas for the processing of molybdenum-copper heat sink materials were provided.Protecting the foil with a salt layer could reduce the embrittlement of the molybdenum foil.This word was for increasing the explosive thickness within the weldability window results in a thicker melting of the molybdenum,which in turn reduces the generation of microscopic cracks.The welding strength of the wave waist region was lower than that of the wave front region,and the thermal stress exceeding the strength limit of the molybdenum foil might be the reason for the formation of microcracks.Delamination cracks in the isotherm direction and interface cracks in the joint direction could be observed.The method of thermal explosion welding could reduce the temperature gradient,thereby improving the bonding quality of the composite plate.From the outer position of the vortex to the center of the vortex,the content of copper element was gradually decreasing,and its molybdenum content was gradually increasing.Therefore,the formation of the vortex depended more on the movement of copper.The molybdenum element in the transition layer was more introduced by element diffusion,while the molybdenum element in the vortex structure was more produced by the melting of molybdenum particles,which would lead to the uneven ratio of molybdenum element in the vortex.Compared with copper at the same distance from the interface,the change in hardness with distance was more significant on the molybdenum side,and its degree of work hardening was higher.Figure 40 Table 29 Reference 96...