| Active material is a kind of energetic material which can produce strong deflagration reaction and release a lot of energy under impact load.Compared with the traditional energetic material,the reactive material has higher mechanical strength and stability.Because this kind of material has the dual characteristics of mechanical strength and energy release,it can be used as a structural material to replace the inert metal structure in ammunition(such as warhead shell,shaped charge liner,etc.).However,at this stage,the theoretical research on this kind of materials is not deep enough.In this paper,the Al/PTFE active material is taken as the research object,and the research methods of theoretical analysis and experiment are used to study the dynamic characteristics and reaction release energy of the this material.The preparation and micro analysis of Al/PTFE specimens were carried out;the SHPB system was constructed to study the dynamic compression characteristics of Al/PTFE specimens;the energy distribution relationship corresponding to the actual impact induced reaction process was established and the evaluation method of each part of energy was determined in terms of the energy release distribution of the impact reaction of Al/PTFE active projectile;based on the activity of Al/PTFE The energy distribution relationship of the impact reaction release energy of the active projectile,the total release energy of the impact reaction induced by the active projectile hitting the target plate and the energy distribution results of each part are evaluated quantitatively.The main research results are as follows:(1)The particle size matching model of Al and PTFE was established,and the particle sizes of PTFE and 2 kinds of Al powders were determined as 34?m,1.5?m and100?m respectively;The process parameters of component mixing were determined based on the mixing mechanism of general powders;the process means of slow pressure boosting was determined after the mixture was pressed and preformed at room temperature;The sintering temperature curve is determined on the basis of considering material properties and task efficiency.Based on the simplified model of PTFE coated Al particles,the coating method of components was determined by combining with micro analysis,and the process effect was comprehensively evaluated.The average coating thickness of PTFE on 1.5?m and 100?m Al particles is 0.066?m and 29.491?m,respectively.(2)Based on the theory of one-dimensional stress wave,the size of specimen,the material and size of compression bar and wave shaper are determined.The SHPB tests were carried out on different specimens under the strain rate of 4000/s,and the dynamic compressive strength of 1.5?m and 100?m Al particles were 40 MPa and 47 MPa respectively.The law of compression-yield-unloading-strengthening was determined during the dynamic compression of Al/PTFE specimens.(3)Based on Ames' s Quasi closed vessel experiment,an experimental system of shock reaction release energy was constructed.The initial kinetic energy and shock reaction release energy of the active projectile impacting the quasi closed vessel were divided into four subsystem energies,i.e.gas product,jet gas product,vessel wall and unreacted fragment.The theoretical calculation and experimental test method of each subsystem energy were determined.(4)The impact experiments of Al/PTFE projectile with different loading speed and Al particle size were carried out.The specific mass reaction release energy of1.5?m-size Al projectile under the loading of 500,450 and 400 m/s and 10 ?m-size Al projectile under the loading of 500m/s are 3.604kJ/g,2.936kJ/g,2.931kJ/g and0.983kJ/g,respectively.The reaction depth of Al particles under 500 m/s loading is about 5?m according to the simplified reaction model. |
PDF Full Text Request