Study On Explosively Compacted Sintered Nano-Cu-Sn Alloy And Its Properties

Explosive compaction is to use the shock wave produced by explosive explosion to compact powder.Under the action of shock wave,powder produces plastic deformation and ultra-high speed consolidation,and the powder is quickly compacted to alloy shape in a short time.Specimens prepared by explosive compaction usually have the characteristics of high density and high hardness.At present,copper-tin alloy specimens prepared by traditional powder metallurgy process usually have relatively low density and hardness,and need further processing(cold rolling,electric pulse treatment)to become high-strength copper-tin alloy.Therefore,this paper selects nano-copper-tin powder as raw material,and analyzes and studies the explosive compaction sintering nano-copper-tin alloy through theory,experiment and numerical simulation.In this paper,the theory of explosive compaction is discussed in detail,and the macro and micro theories of explosive compaction are discussed.The loading process and unloading process of powder induced by shock wave were analyzed theoretically,and the p-v relation of copper-tin powder was calculated.The JWL parameters of explosives at different detonation speeds are analyzed and studied.The causes of Mach reflection were analyzed theoretically,and the Mach hole and loose powder region where the central powder appeared were studied,which provided theoretical guidance for the subsequent experiment and numerical simulation.In this paper,the best ratio of powder to powder for explosive compaction of nanocopper-Sn alloy under different devices is studied.The best ratio of powder to powder for explosive compaction of nano-copper-Sn alloy under two devices is obtained,which is0.917 for single-layer tube and 1.292 for double-layer tube.A device is designed to reduce the influence of Mach reflection on powder(center bar device).The experiment shows that the device can reduce the influence of Mach reflection.The results show that if the detonation velocity is greater than 3467m/s,cracks or Mach holes will appear at the axial position of the specimen,but if the detonation velocity is too low,the axial discharge compaction will be incomplete.The experimental results show that when the detonation speed of emulsified explosive is adjusted to around 3467m/s,the nano-copper-tin alloy bars with better shape can be prepared.The particle size and initial density of nanometer copper-tin powder were analyzed,and the smaller the particle size,the more energy absorbed,the more difficult to be compacting.And the higher the initial density,the better the compaction effect will be,but when the initial density exceeds 52%,the impact of increasing the initial density is small;The experimental research on underwater explosive compaction is carried out.The research proves that underwater explosive compaction under the same condition can improve the absorption of powder impact energy generated by explosive explosion and improve the compaction effect.The numerical simulation of explosive compaction process was carried out by LSDYNA software,and the pressure change and deformation of powder were simulated.The powder distribution in the process of explosive compaction was simulated under different detonation velocity and initial density.The simulation results show that in the process of explosive compaction,the highest internal pressure of the powder is at the intersection of the top shock wave and the side shock wave.With the progress of sliding detonation,Mach reflection is more easily generated at the bottom of the powder.The simulation analysis of different detonation velocity shows that increasing detonation velocity can increase the internal pressure of powder,improve the deformation degree of powder and strengthen the compaction effect,but too high detonation velocity will lead to the severe Mach reflection in the center of the powder leading to the failure of the specimen.In the numerical simulation of copper tin powder with different initial density,it is found that the internal pressure of the powder increases with the increase of initial density,and the compaction density increases with the increase of initial density,and then tends to be stable,which is consistent with the experimental results.