快速凝固Mg-35Zn-13Nd合金的退火组织与性能研究

Behaviors of annealed microstructure and property in rapidly solidified Mg-35Zn-13Nd alloy

为改善常规凝固条件下镁合金微观组织粗大,力学性能较差等缺点,用单辊快速凝固法制备了Mg52Zn35Nd13合金急冷薄带.采用透射电镜、X射线衍射仪、热分析仪等手段研究了急冷态及退火态薄带的显微组织、相结构转变与性能特点.实验结果表明:急冷薄带显微组织中存在大量非晶态结构.退火处理发现,在本实验条件下,102℃×3h退火条件下薄带显微组织结构最佳,力学性能最好.而后薄带微观组织将随退火温度的不断升高而明显粗化,力学性能不断下降.该合金成分具有一定的非晶成形能力;快速凝固工艺可显著改善镁合金微观组织粗大等缺陷;适当的退火工艺可进一步优化急冷薄带微观组织并获得更好力学性能.

To improve the coarse microstructure and mechanical properties of magnesium alloy under conditions of conventional solidification,single-roll rapid solidification ribbon of Mg52Zn35Nd13 alloys was prepared by quenching. The microstructure,phase structure transformation and performance characteristics of quenching state and annealed ribbons were studied by means of transmission electron microscopy,X-ray diffraction,and thermal analysis instrument. Experimental results show that a large number of amorphous structures exist in quench microstructure of thin strip. The best thin strip microstructure and mechanical properties can be obtained through annealing for 3 h at 102 ℃. Then the microstructure of thin strip turns to be coarse with rising annealing temperature,and its mechanical properties are weakened. The alloy composition has a certain capability of amorphous forming. Rapid solidification process can significantly improve the coarse microstructure of magnesium alloy. Appropriate annealing process can further optimize the quenching microstructure of thin strip and achieve better mechanical properties.