差相磁场对水平连铸7075铝合金锭坯组织与性能的影响

Effects of Out-phase Electromagnetic Field on the As-cast Microstructure and Mechanical Properties of HDC (Horizontal Direction Continuous) Casting 7075 Aluminum Alloy Ingot

采用宏微观组织观察和拉伸试验,研究了差相磁场对铝合金水平连铸7075铝合金锭坯组织与力学性能的影响。结果表明,差相磁场可以显著改善7075铝合金铸锭的铸态组织,使粗大不均匀的羽毛晶转变成细小均匀的等轴晶。致密性好、无疏松的羽毛晶的抗拉强度明显高于致密性差、存在大量疏松的等轴晶的抗拉强度;差相磁场使铸锭的组织更加均匀。

Effects of out-phase electromagnetic field on as-cast microstructure and mechanical properties of the 7075 aluminum alloy ingot were investigated by macro-microstructure observation and tensile testing. The results reveal that out-phase electromagnetic field can convert coarse heterogeneous feathery grain into fine equiaxed ones,greatly improving the microstructure in the 7075 alloy. Tensile strength of the 7075 alloy ingot is closely related to density of the microstructure and porosity(gas hole) . Tensile strength of the alloy ingot with compact and porosity-free feathery grain is remarkably superior to that of ones with low compact and high porosity equiaxed grain. Out-phase can effectively improve the microstructure and mechanical properties of the ingot.