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对超声细化和未细化的AZ31镁合金棒料进行均匀化退火后热挤压,并对热挤压后的组织和硬度进行了对比分析。结果表明,与未经过晶粒细化处理棒料的热挤压组织相比,预先经过晶粒细化处理的AZ31镁合金棒热挤压组织更加均匀。当挤压比λ为16、挤压料温度为380℃、挤压速度为0.9 m/min时,组织发生回复再结晶。与未经晶粒细化处理棒料的挤压组织相比,经过晶粒细化处理的挤压组织更加细小;挤压速度增加到10 m/min时,经过晶粒细化处理后的AZ31镁合金挤压变形后棒料边缘容易发生二次再结晶现象,形成一条宽约75μm的粗晶组织,边缘附近区域组织中有孪晶形成。同时,经过晶粒细化处理后的AZ31镁合金挤压棒的硬度较高。
The ultrafine and refined AZ31 magnesium alloy bars were homogenized and hot extruded. The microstructure and hardness of the AZ31 magnesium alloy bars after hot extrusion were compared. The results show that the AZ31 magnesium alloy rod pre-processed by grain refinement has a more uniform hot extrusion structure than the hot-extruded structure without grain refinement. When the extrusion ratio λ is 16, the extrusion temperature is 380 ℃ and the extrusion rate is 0.9 m / min, the structure recovers and recrystallizes. Compared with the extruded structure without grain refinement, the extruded structure with grain refinement is finer. When the extrusion speed is increased to 10 m / min, the grain size of AZ31 Magnesium alloy extrusion deformation of the bar edge prone to secondary recrystallization phenomenon, the formation of a coarse grain size of about 75μm, near the edge of the organization twins. At the same time, after the grain refinement treatment AZ31 magnesium alloy extrusion rod hardness higher.