Key Issues In Superplastic Forming Of Amorphous Alloy MEMS Fuze Safety Mechanism

Fuze is the core of the weapon system's goal to destroy,and directly determines the success or failure of the weapon system and the target.The use of micro-electromechanical systems?MEMS?for fuzes will greatly increase the miniaturization,intelligence,and precision strike capabilities of weapons and equipment.In MEMS fuzes,safety agencies directly determine the safety and reliable detonation of fuzes.This requires that the materials used have excellent mechanical properties and good micro-nano scale forming capabilities.However,the materials used in fuze safety agencies currently have weak impact resistance,low strength,difficulty in micro/nano-scale processing,and high cost.It seriously affects the reliability and precision strike capability of precision-guided weapons.Due to the absence of grains,amorphous alloys have a series of mechanical properties that are significantly better than those of crystalline materials,and can achieve near net shape formation at micro-and nano-scales.The use of amorphous alloys for MEMS fuze safety mechanisms not only solves the material problems of current MEMS fuze safety agencies,but also significantly increases the reliability,intelligence,and precision strike capabilities of weapons and equipment.This paper systematically studies the superplastic forming of amorphous alloy MEMS fuze safety mechanism,and measures the interface friction factor in forming of amorphous alloy.Firstly,Zr₃₅Ti₃₀Cu_8.25Be_26.75?at.%?alloy ingots with uniform composition were prepared by arc smelting,and then the amorphous alloy sheet was prepared by injection molding.Differential scanning calorimetry?DSC?was used for thermal analysis of the prepared amorphous alloy to obtain the glass transition temperature,crystallization temperature and the width of supercooled liquid region of the amorphous alloy.The three-dimensional structure of the"W"spring was designed by Creo 3D modeling software.The finite element simulation of the micro spring was simulated using the universal finite element simulation software Ansys.The stress distribution of the spring was obtained and the stress concentration point of the spring was predicted.Using a silicon mold with a micro-spring structure as a template,a flat micro-spring tensile specimen and an MEMS fuse are formed on the surface of an amorphous alloy in a supercooled liquid region?390°C?at a strain rate of 0.001 s^-1.Security agency.X-ray diffractometer?XRD?examination showed that the amorphous alloy did not crystallize after thermoplastic forming.Microstructures were characterized by optical microscopy and scanning electron microscopy.The shape of the formed microsprings was observed to be intact.The electro-dynamic static fatigue tester was used to test the tensile strength of the amorphous alloy flat micro-springs,and the elastic coefficient was 0.0135 N/mm.The microspring can withstand a maximum force of 1.54N and can generate a deformation of 539%.The fracture morphology of the spring was observed and the fracture form was analyzed as ductile fracture.In order to solve the influence of interfacial friction on the forming ability of amorphous alloy microforming,the effects of quasi-static and ultrasonic vibrations on the friction factor were studied comparatively.The results show that the ultrasonic vibration can significantly reduce the friction,such as the quasi-static 1/3 friction coefficient of amorphous alloy thermoplastic forming.This shows that the use of ultrasonic vibration technology can effectively improve the superplastic forming ability of amorphous alloys.