摩擦旋轉攪拌製程對AZ31鎂合金晶粒細化之研究

Grain Size Refinement in AZ31 Magnesium Alloy by Friction Stir Processing

張志溢(C. Y. Chang) ； 李敬仁(C. J. Lee) ； 黃志青(J. C. C. Huang)

《材料科學與工程》 37卷2期 (2005/06) Pp. 75-81

https://doi.org/10.6409/JMSE.200506.0075

摘要

本研究探討摩擦旋轉攪拌製程用於AZ31鎂合金的基礎性質及摩擦旋轉攪拌製程對AZ31鎂合金的改質和晶粒細化；並系統性的探討摩擦旋轉攪拌製程所得之晶粒大小與其工作應變速率及溫度之相關性，並使用Zener-Holloman參數來量化其關係，以及使用X光繞射分析研究銲道之晶粒取向。

關鍵字

摩擦旋轉攪拌製程 ； 鎂合金 ； 微結構組織 ； 熱機處理製程

並列摘要

Friction stir welding (FSW) is a solid state joining method. The process produces high-quality, defect-free joints with better mechanical properties than fusion welding processes. Recently, friction stir processing (FSP), an adaptation of friction stir welding, has been demonstrated to be an effective means of refining grain size of cast or wrought aluminum via dynamic recrystallization. FSP is an effective grain size refinement technique when processed under the proper conditions. In the present result, grain size of AZ31 Mg can be refined from 75m to 0.6m. The relationship between the resulting grain size and the applied working strain rate and temperature for the friction stir processing in the AZ31 Mg alloy is systemically examined. The Zener-Hollomen parameter is utilized in rationalizing the relationship, and it was found that the relationship of 1n d=8.7-0.27 1n Z is followed. The temperature rise during FSP is traced, and the maximum temperature can reach 250-450℃, depending on the FSP pin rotation speed. Based on systematic hardness measurements of the base and FSP specimens, the Hall-Petch relationship is well followed, i.e., Hv=40+72 d-1/2. The grain orientation distribution is also studied using the X-ray diffraction, and the results show that, in the FSP dynamically recrystallized zone, the (0002) basal plane tends to lie on the transverse plane at lower pin rotation speeds, and approaches to nearly random orientation at higher rotation speed.

並列關鍵字

Friction stir processing ； Magnesium alloy ； Microstructure ； Thermomechanical processing