Die-casting Simulation Of Bulk Zr-based Amorphous Alloys

Since the discovery of amorphous alloys,they have been widely investigated,owning to their excellent mechanical properties and internal structure which are different from traditional crystalline alloys.Among them,Zr-based amorphous alloys have very excellent forming abilities and have the potential to be made as bulk amorphous alloys.The die-casting process is a production method that can prepare massive Zr-based amorphous alloys in large quantities.The casting products obtained by die-casting have good surface finish,high dimensional accuracy,and the strength and hardness are higher than those obtained by traditional sand casting.In this paper,Proe,the finite element modeling software,was used to model the die casting model.The casting mold flow software Procast was used to separately analyze the plate castings with a thickness of 1,1.5,2,2.5 mm and cylindrical castings with a diameter of 1,1.5,2,3,4,6,8,10 mm,which were subjected to die-casting simulation analysis under different die-casting parameters.The flow field of the molten metal filling process and the temperature field changes of the cooling process can be obtained,and then the influence of different die-casting parameters on crystal forming ability can be obtained.The T_g of different thicknesses at the center of the plate casting obtained under different die-casting parameters are greater than 10?/s,which satisfies the critical cooling rate condition for the formation of Zr-based amorphous alloys.As the thickness of the plate casting increases,the cooling rate at T_g decreases,and the amorphous forming ability is reduced.When the die-casting speed increases from 4 m/s to 9 m/s and 15 m/s,the cooling rate at T_g has not been significantly improved with the die-casting speed.The filling quality of die cast at 4 m/s and 9 m/s is better than that of die cast at 15 m/s.When the die casting temperature is increased from 1400?to 1500?and 1600?,the cooling rate at T_gwill increase as the die-casting temperature decreases,and the amorphous forming ability will increase.When the mold preheating temperature increases from 473?to 493?and513?,the cooling rate at T_g decreases with the decrease of the mold preheating temperature.When the used mold material is Cu mold,the cooling rate at T_gwill increase,and the amorphous molding ability will be improved.When the cooling water channel is added to the H-13 steel mold,the cooling rate at Tg is significantly increased,and the amorphous forming ability is improved.For cylindrical castings,when the die casting speed increases from 4 m/s to 9 m/s and15 m/s,the cooling rate at T_g at the center of cylindrical castings with diameters of 1,1.5,2,3,4,6 mm are greater than 10?/s,which satisfies the critical cooling rate condition for the formation of Zr-based amorphous alloys.The cooling rate at T_g at the center position of cylindrical castings of 8 and 10 mm are less than 10?/s,which can't satisfy the critical cooling rate condition for the formation of Zr-based amorphous alloys.With the increase of die-casting speed,the cooling rate at T_g does not increase significantly,due to the phenomenon of liquid splashing,cylindrical castings will have porosity defects;as the diameter of the cylinder increases,the cooling rate at T_gdecreases,and the amorphous forming ability decreases.When the mold preheating temperature drops from 493?to473?,on the whole,the cooling rate at T_gof cylindrical castings of different diameters will increase,the cooling rate at T_g at the center position of cylindrical castings of 8 and10 mm is still less than 10?/s,and the forming ability of amorphous alloys is improved.In summary,Procast software can analyze the flow field and temperature field and help understand the influence of die-casting parameters on the forming quality of amorphous casting products and the amorphous forming ability.