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| 径锻AZ61镁合金退火后晶粒长大及组织演变规律 |
| Grain Growth and Microstructure Evolution Law of Radial Forged AZ61 Magnesium Alloy after Annealing |
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| DOI：10.3969/j.issn.1674-6457.2023.04.005 |
| 中文关键词: 镁合金 退火 径向锻造 晶粒长大 组织均匀性 |
| 英文关键词: magnesium alloy annealing radial forging grain growth structure uniformity |
| 基金项目:国家自然科学基金(U1910213，52205400);山西省重点研发计划(201903D121088);太原科技大学博士科研启动基金(20222046) |
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| 中文摘要: |
| 目的 通过研究径锻AZ61镁合金棒材在后续退火处理时的晶粒长大和组织均匀性演变行为，构建等温条件下径锻AZ61镁合金晶粒长大模型，总结径锻镁合金退火后组织均匀性演变规律，为此棒材后续热处理工艺的制定提供理论借鉴和指导。方法 基于系统的等温正交退火试验，量化统计各退火条件下样品组织的平均晶粒尺寸和晶粒尺寸分布，分析径锻AZ61镁合金棒材的晶粒长大行为和组织均匀性演变规律。结果 退火后，径锻AZ61镁合金组织中晶粒趋于长大。在250~300 ℃温度区间内，晶粒长大速度较为缓慢。随着退火温度的升高，晶粒长大速率随之上升，尤其是退火温度升高到450 ℃以后，晶粒长大速率显著增大。当退火温度一定时，退火起始30 min内，晶粒快速长大。在之后的长时间退火过程中，晶粒长大速度逐渐放缓。同时，随着退火的进行，锻后样品中存在的超细晶条带状组织逐渐消失，样品组织均匀性显著提高。结论 通过研究晶粒长大现象构建的等温条件下径锻AZ61镁合金晶粒长大模型与试验结果拟合良好。结合组织均匀性演变规律，径锻AZ61镁合金退火后的组织状态能够被很好地预测。 |
| 英文摘要: |
| The work aims to establish a grain growth model of radial forged AZ61 magnesium alloy bars under isothermal condition by studying the grain growth and microstructure uniformity evolution behavior during subsequent annealing treatment, and summarize the microstructure uniformity evolution law of radial forged AZ61 magnesium alloy after annealing, so as to provide theoretical reference and guidance for formulation of subsequent heat treatment process of bars. Based on the systematic isothermal-orthogonal annealing experiment, the average grain size and grain size distribution of samples under different annealing conditions were quantified, and the grain growth behavior and structure uniformity evolution of radial forged AZ61 magnesium alloy bars were analyzed. The grain size in radial forged AZ61 magnesium alloy tended to grow with annealing. At 250-300 ℃, the grain growth rate was relatively slow. As the annealing temperature increased, the grain growth rate increased, especially after the annealing temperature increased to 450 ℃, the grain growth rate increased significantly. When the annealing temperature was constant, the grains grew rapidly within the first 30 min of annealing. In the subsequent long time annealing, the grain growth rate gradually slowed down. Meanwhile, the ultrafine-grained bands in the forged samples gradually disappeared during annealing, and the microstructure uniformity was improved significantly. In this work, the grain growth model of radial forged AZ61 magnesium alloy under isothermal conditions constructed by studying grain growth phenomenon is in good agreement with the experimental results. Combined with the evolution law of structure uniformity, the microstructure of radial forged AZ61 magnesium alloy after annealing can be well predicted. |
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