Numerical Simulation Of Canned Extrusion Process Of Aluminium-based Amorphous Alloys

Aluminium-based amorphous alloys have ultra-high specific strength, good thoughness and properties of the corrosion resistance and the abrasion resistance. But this system has a very limited glass forming ability, it is difficult to obtain bulk sized samples. The use of the viscous rheological behavior of amorphous alloy in the supercooled liquid provides opportunities for amorphous powders to consolide dense bulk amorphous materials. In this paper, based in Al-Ni-Y-Co-La amorphous alloy, prepare good amorphous powders by gas atomization method, and then prepare high density of Al-based bulk amorphous alloys. While the temperature and stress distribution have a closed related with process parameters in the extrusion. Because of non-visualization and complicated boundary conditions of the extrusion, it is difficult to control process.This paper uses finite element method to simulation the canned extrusion process of Al86Ni6Y4.5Co2La1.5amorphous alloys powder, researchs the choice of sleeve materials, the design of mold structure, the optimization of extrusion parameters, such as ram speed and extrusion radio, and the temperature distribusion in the extrusion process and so on, in order to work out the best extrusion process.Some important results are listed as following:1. The choice of sleeve materials. Select1011,6062and2024Aluminium alloy as sleeve materials. The simulation results indicate that:selecting6062Aluminium alloy as sleeve materials makes the strength match situation with amorphous powder good, deformation stable and Stress-Effective distribution uniform.2. The design of mold structure. Design four kinds of exit angle for the mould, rounded corner,30°,45°and60°. The simulation results indicate that: when the exit angle is rounded comer, the sleeve and workpiece can smooth extrude the mould, the sectional dimension of workpiece can stay stable, the Stress-Effective distribute uniformly, the efficiency of extrusion is high. 3. The optimization of extrusion process parameters. Select three kinds of ram speed: lmm/s,2mm/s,4mm/s and four kinds of extrusion radio:4:1,10:1,20:1. The simulation results indicate that:when the ram speed is2mm/s and extrusion radio is4:1, the deformation of sleeve and workpiece is good, flow velocity is stable, Stress-Effective distribution is uniform, it is not easy to cause defects.4. The temperature distribution in the extrusion process. The simulation results indicate that:in the transitional period and time stayed in the mould, because of convection heat transfer coefficient and contact heat transfer coefficient, the temperature distrubutes uniformly and has a little decreased on the whole; in the period of extrusion, in the deformation zone, because of friction heat and deformation heat, the tenperature of sleeve and workpiece has partly risen, which makes the plastic rheology capacity of workpiece enhanced, and improves the uniformity ofdeformation.