快速凝固AZ31镁合金的微观组织与力学性能

Microstructure and Mechanical Characteristics of Rapidly Solidified AZ31 Magnesium Alloy

  • 摘要: 基于单辊快速凝固工艺,分析了不同辊速条件下AZ31镁合金的带材组织及其250 ℃热挤压棒材的力学性能。结果表明,带材截面微观组织存在的急冷定向凝固区和缓冷等轴晶区,是受温度梯度影响产生的微观组织分区现象;熔体冷却时裹气产生隔热区,导致带材微观组织均一度降低;在17.58 m/s最优辊速条件下,AZ31镁合金的250 ℃热挤压棒材的屈服强度和伸长率分别达到360 MPa和14.47 %。

     

    Abstract: AZ31 magnesium ribbons are prepared by the single roll rapid solidification method at different rolling speeds, and the microstructures are analyzed. The mechanical properties of AZ31 magnesium rods extruded at 250 ℃ from the ribbons are investigated. Results indicate that the rapid cooling directionally solidification region and gradual cooling equiaxed grain region are found in the cross-sections of the AZ31 magnesium ribbons, which is a thermal-gradient driven microstructure partition phenomenon. The heat insulation zone forms due to the gas entrapment in the melt pool, leading to the decline of microstructural homogeneity of the ribbons. It is found out that when the rolling speed is 17.58 m/s, the AZ31 magnesium rods extruded at 250 ℃ from the ribbons have the optimal performance, with the yield strength up to 360 MPa and the elongation up to 14.47 %.

     

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