Effect Of Alternating Electromagnetic Field On The Microstructure And Property Of Vacuum Counter-pressure Casting Aluminum Alloy

Vacuum counter-pressure casting is an advanced anti-gravity precision casting forming technology in the field of aerospace, defense, automotive and other industries with the feather of using large, complex thin-walled non-ferrous alloy castings, which have a greater advantage and broad application prospects. The casting solidification process control of vacuum counter-pressure is one of the key technologies to obtain high-quality castings. Meanwhile, the effect of using the electromagnetic technology to improve the metal solidification structure is remarkable and electromagnetic field technology used in the field of vacuum counter-pressure casting will further affect the casting solidification process. Therefore, the study of aluminum alloy microstructure and mechanical properties of vacuum counter-pressure casting in the alternating electromagnetic field has important theoretical and practical significance.Alloy ZL114A was the main research object used in this article. The effect of the aluminum alloy casting microstructure and mechanical properties in gravitational environment and vacuum counter-pressure casting environment were studied, which in order to receive the influence law of microstructure and mechanical properties of casting under different crystallization pressures in alternating electromagnetic field. The results show that:the alternating magnetic field current intensity and crystallization pressure have strong impacts on the microstructure and mechanical properties of casting. With the increase of the crystallization pressure and the magnetic field current intensity, casting tensile strength and elongation increased, the secondary dendrite arm spacing decreases, and the grain size becomes finer. Whereas magnetic field current intensity above10A, the tensile strength will lower and the secondary dendrite arm spacing increases, the grains become coarse. At the same time, the relationship of crystallization pressure and alternating electromagnetic field interactions with the secondary dendrite arm spacing were received as follows: λ2=61.22143-1.16158I-0.14385PC+0.07273I2+1.6726x10-4PC2With the alternating magnetic field current intensity10A and crystallization pressure400KPa, vacuum pressure casting aluminum alloy castings have the highest mechanical properties, while the secondary dendrite arm spacing is smallest and have the smallest structure. When the crystallization pressure is less than300KPa, alternating magnetic field current strength has a big effect on the structure and mechanical properties; when crystallization pressure above400KPa, it will have a notable effect on the microstructure and mechanical properties.The findings of the thesis provides the theoretical basis and technical support for solidification controlling process of the vacuum counter-pressure casting in external physical fields, and laid a solid foundation for the promotion and application of vacuum counter-pressure casting technology.