旋转磁场对AZ91D-0.4%RE合金组织和性能的影响

Effects of Revolving Magnetic Field on Microstructure and Properties of AZ91D-0.4%RE Alloy

研究旋转磁场对AZ91D-0.4%RE镁合金显微组织、力学性能及耐腐蚀性能的影响。结果表明:在磁场作用下,合金中α-Mg树枝晶显著细化,晶粒大小更趋均匀;形成的稀土化合物Al11RE3尺寸减小,由鱼骨状、长针状逐渐向短针状转变。施加旋转磁场后,合金的抗拉强度、屈服强度、延伸率和硬度可比未施加磁场时分别提高13%,15%,44%,19%。拉伸断口表现为准解理断裂方式。同时,合金的自腐蚀电位提高,表明其耐腐蚀性能提高。

The effects of revolving magnetic field on the microstructure, mechanical properties and corrosion resistance of the AZ91D-0.4%RE alloy were investigated. It is found that under the revolving magnetic field, the grain size of α-Mg dendrite was obviously decreased and became more uniform with the increasing of excitation voltage; the additional phases of Al11RE3 became smaller and changed from fishbone or long-acicular structure to short acicular structure gradually. Under the revolving magnetic field, σb, σ0.2, δ and hardness of the alloy can be increased by 13%, 15%, 44% and 19%, respectively. The room-temperature tensile fracture shows a feature of quasicleavage fracture. Meanwhile, the self-corrosion potential increased from –1.56 V to –1.51 V, indicating that the corrosion resistance was greatly enhanced.