采用软接触电磁连铸法制备了AZ61镁合金铸锭,对其晶体结构、金相组织、力学性能及抗腐蚀性能进行了研究,并与金属模铸法制备的铸锭作了比较。实验发现:两种方法制备的铸锭相结构相同;软接触电磁连铸铸锭晶粒细小,第二相弥散分布,促使其力学性能有很大提高,常温抗拉强度和延伸率分别提高了约30%和27%,其断口形貌具有更多韧性断裂的特征;在3.5%NaCl溶液中的动电位极化测试表明,软接触电磁连铸可以使镁合金的自腐蚀电压升高,腐蚀电流密度降低,从而提高镁合金的耐腐蚀性能。
The effects of soft-contact electromagnetic casting (EMC) on the phase constitution, microstructure, mechanical property, and corrosion resistance of AZ61 magnesium alloy were investigated by comparing with the die cast ingot. Results show that the ingots made by different methods have the same phase constitution. The soft-contact EMC ingots have more fine and uniform grain structure, which improves the mechanical property of magnesium alloys. The ultimate tensile strength and elongation of soft-contact EMC specimens increase by about 30% and 27%, respectively. Moreover the fracture morphologies of soft-contact EMC specimens have more characters of gliding fracture. The potentiodynamic polarization indicates that the soft-contact EMC ingots have much better corrosion resisting property than the die cast ones because the better microstructure of soft-contact EMC improves the corrosion potential and decreases the corrosion current density.