Research On Flexible Microblanking Of Amorphous Alloy Under Laser Dynamic Loading

Amorphous alloys have excellent mechanical properties,but due to their poor macroscopic plasticity at room temperature,it is easy to have destructive fracture under the action of external force,which will restrict the application of traditional microblanking in the processing of amorphous alloy microholes.Aiming at this problem,this dissertation proposes the flexible microblanking of amorphous alloys under laser dynamic loading.The research mainly includes the basic theory of laser dynamic loading and amorphous alloy deformation,the microblanking of different profile workpiece and the composite microforming.The main research work and achievements are as follows:(1)The formation mechanism of laser force effect under laser dynamic loading and the simplified model of shock wave pressure are studied.The supercharging effect and homogenization pressure effect of shock wave propagation in soft film are investigated.The plastic deformation and fracture behavior of amorphous alloys are investigated,which provides a theoretical basis for subsequent experimental studies.(2)The laser dynamic loading flexible microblanking experiment system was constructed,the microblanking experiment of the complex profile workpiece of Febased amorphous alloy was carried out.the fracture morphology of the workpiece was studied,the process window of laser energy and soft film thickness was established,the influence of laser energy on the mechanical properties and surface quality is revealed.The study found that: the profile of the workpiece has consistency with the mold;The fracture surface is mainly composed of smooth zone and veined zone,which shows that there are macro brittle fracture and micro plastic fracture in the workpiece;When the laser energy is 1520 mJ,the soft film thickness is 200?m,the workpiece can achieve a balanced forming effect;With the laser energy increases,the nanohardness and surface roughness increases first and then decreases.(3)The microblanking experiment of the array profile workpiece of Fe-based nanocrystalline alloy was carried out.The influence of laser energy and soft film thickness on the forming accuracy,the morphology and the creep behavior of the workpiece were studied.The study found that: with the increase of laser energy,the forming accuracy is improved.The fracture surface morphology is also composed of slip zone and veined zone,and there are a large number of melted droplets and shallow pits in the veined zone.The creep behavior of the workpiece is mainly composed of two stages: transient creep and steady-state creep;As the creep time increases,the stress index gradually reaches a stable state;As the load increases,the stress index also increases accordingly,reflecting the obvious maximum load dependent effect.(4)The composite microforming experiments of forming,punching and blanking of Fe-based amorphous alloys were carried out.The effects of annealing temperature,laser energy,and soft film thickness on the forming accuracy,the morphological characteristics,the thickness distribution and the mechanical properties were explored.The study found that: Annealing temperature below 250? helps to release the stress inside the material and improve the forming accuracy;As the laser energy increases,the forming accuracy also increases;But when the laser energy is too large,the forming depth will reduce;The thinner the soft film thickness,the higher the forming accuracy.A large number of shear bands are distributed on the surface of the workpiece,indicating that the plastic deformation of the workpiece is based on the generation and propagation of shear band.The fracture morphology is also composed of smooth zone and veined zone.The different region of the workpiece,the proportions of the two parts are different.The distribution of nanohardness is roughly the same as that of thickness.The thinner the thickness,the smaller the nanohardness.The elastic modulus of the workpiece decreases gradually from the flange area to the bottom.In this dissertation,research on flexible microblanking of amorphous alloys under dynamic laser loading is carried out,revealing the forming law of amorphous alloys under laser impact,which provides theoretical basis and experimental guidance for the subsequent research and application.