| Metal electric explosion-driven flyer technology is an important dynamic high-pressure loading technology.The slapper detonator is an application product using electric explosion-driven flyer technology,which has been widely concerned in weapons.However,due to the low energy transduction efficiency of the electric energy into the kinetic energy of the flyer,it is difficult to adapt to the development needs of the weapon systems.It is urgent to improve the energy conversion efficiency,safety,reliability,and integrate of the current electric explosion film.Therefore,this dissertation proposes to use the Al/Ni energetic multilayer films(EMFs)as electric explosion film to significantly improve the energy transduction efficiency.Specifically,this dissertation systematically invesitigated the preparationand characterization of Al/Ni EMFs,the characteristics of the electrical explosion and plasma flow field,the alloying reaction mechanism,and performance of slapper detonator incorporating Al/Ni EMFs,etc.(1)The Al/Ni energetic multilayer films with different modulation periods were prepared by magnetron sputtering,respectively.The as-deposited Al/Ni EMFs wascharacterized by many analytical methods,including TEM,XRD,AFM,DSC,XPS and APT to analyze the microstructure,chemical composition,roughness,heat release and interface structure.The results showed that the as-deposited films have a high quality without holes or cracks.The Al layer and Ni layer was arranged periodically with controlled thickness,and different layers can be distinguished easily.The films existed in the form of Al and Ni with a polycrystalline state.Asymmetric atomic interdiffusion thickness at the interfaces of Al layer and Ni layer was formed.For the Al/Ni EMFs with 500 nm modulation period,the total intermixing and interdiffusion region by Al atoms deposited on Ni layer had thickness of 42 nm.However,the value by Ni atoms deposited on Al layer was only 24 nm.Meanwhile,the effects of annealing temperature and modulation period on the phase evolution,microstructrue and atomic diffusion of Al/Ni EMFs were investigated.The results showed that when the modultiaon periods were less than 100 nm,the alloying reaction starts at 473 K and ends to 573 K.When the modulation periods were greater than 100 nm,the onset temperature of alloying reaction was prolonged to 573 K.In addition,an abnormal atomic diffusion behavior was noticed in which Ni atoms only diffuses to the upper Al layer during the annealing process.The phenomenon was originated by the inconsistency interface of the as-deposited Al/Ni EMFs.(2)The Al/Ni energetic bridge foil was fabricated using MEMS technology.The effects of modulation periods on the electric explosion characteristics of Al/Ni energetic bridge foil were studied.It indicated that the explosion time and driving flyer energy was related to the modulation period.It can effectively reduce the explosion time and improve the driving flyer energy by reducing the modulation period of the Al/Ni EMFs.The Al/Ni energetic bridge foil with 25 nm modulation period possessed the shortest explosion time and largest driving flyer energy compared to samples with 250 nm and500 nm.(3)Based on the principle of molecular dynamics calculation,a model of Al/Ni EMFs was established.The influence of the initial temperature and modulation period of the Al/Ni EMFs on the reaction temperature,reaction time and reaction rate was analysized.The simulation showed that when the initial temperature was lower than the melting temperature of Al,the alloying reaction rate was slow due to solid diffusion.When the initial temperatue has reached the melting temperatue of Al,the alloying reaction rate was significantly increased because of higher liquid diffusion coefficenct.Meanwhile,with the increase of modulation period,the time of completing alloying reaction decreased indicating violent reaction.It was indicated that the Al/Ni EMFs with 25 nm modulation period could release the chemical heat during electrical explosion process,resulting highest energy transduction efficiency.The reaction mechanism of Al/Ni EMFs under pulse current was described in this dissertation.Due to the low melting point of Al atoms,the Al layer was preferentially reached to the melting process of Al/Ni EMFs.The melted Al atoms can aggravate the diffusion of Ni atoms into the Al layer,which formed Al Ni intermetallic compounds at the interface of the Al and Ni layer.During the process,the melted Al layer can still maintain integrity with a certain extent and the volume has not expanded significantly.Therefore,the Al Ni intermetallic compound can continue to nucleate and grow.The characterization of the final products after the electrical explosion of the Al/Ni EMFs showed that the Al Ni intermetallic compound was the only existence,which was consistent with reaction mechanism.(4)The characteristics of the electrical explosion plasma integrated by Al/Ni EMFs were meansured by atomic emission spectroscopy and shadow imaging.The influence of modulation period and inputting electrical energy on plasma thermodynamics and dynamics was investigated.The results showed that the highest electron temperature and density belongs to Al/Ni energetic bridge foil with 25 nm modulation period.Therefore,the Al/Ni energetic bridge foil with 25 nm modulation period could produce faster expansion speed of plasma jet and shock wave.(5)The accerelating flyer characteristics of the Al/Ni energetic bridge foil were studied.The influence of the modulation period on the flyer velocity was analyzed.The results showed that the highest flyer velocity belonged to Al/Ni energetic bridge foil with 25 nm modulation period.Compared with the traditional Cu bridge foil,the value of flyer velocity has increased by about 28% integrated with Al/Ni energetic bridge foil with 25 nm modulation period.The slapper detonator were designed and fabricated based on Al/Ni energetic bridge foil.The effect of the barrel diameter on initiation performance was investigated.The results showed that the initiation sensitivity of HNS-IV was the highest of slapper detonator with a barrel diameter of 0.8 mm.The initiation sensitivity of slapper detonator with the barrel diameter of 0.6 mm and 0.4mm to HNS-IV was basically the same.The above application research results can provide technical support for the design and preparation of slapper detonator with high energy transduction efficiency. |
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