Mn添加对挤压态Mg-Zn-Y-Nd合金微观组织和腐蚀行为的影响

Microstructure and corrosion behavior of extruded Mg-Zn-Y-Nd alloy respect to Mn addition

摘要:

通过光学显微镜，配备能量色散光谱仪的扫描电子显微镜，X射线衍射仪，浸泡法和电化学测试的方法研究了Mn的添加对挤压Mg-Zn-Y-Nd合金在3.5wt.％NaCl溶液中的微观组织和腐蚀行为的影响。结果表明，在研究的Mg-Zn-Y-Nd合金中添加Mn可以诱导Mg3Y2Zn3（I相）沉淀，可以抑制热挤压过程中动态再结晶（DRX）晶粒的粗化。同时，添加了Mn也可以提高合金的耐腐蚀性。不含Mn的Mg-5.6Zn-1Y-0.4Nd合金与含锰1.0 wt.％的Mg-5.6Zn-1Y-0.4Nd合金腐蚀速率分别为18.78 mm·y-1和9.89mm·y-1。而耐腐蚀性的提高主要归因于腐蚀产物层保护性的增强。

Abstract:

The effect of Mn addition on the microstructure and corrosion behavior of extruded Mg-Zn-Y-Nd alloy immersed in 3.5 wt.% NaCl solution were studied by optical microscope, scanning electron microscope equipped with energy dispersive spectroscope, X-ray diffraction, immersion, and electrochemical measurements. Results suggest that the Mn addition in the studied Mg-Zn-Y-Nd alloy can induce Mg3Y2Zn3 (I-phase) precipitation which may inhibit dynamic recrystallizaiton (DRX) grain coarsening during hot extrusion. Meanwhile, its corrosion resistance was improved owing to the addition of Mn. The corrosion rates of free and 1.0 wt.% Mn containing Mg-5.6Zn-1Y-0.4Nd alloys were 18.78 and 9.89 mm·y?1, respectively. The improvement of corrosion resistance is mainly due to an enhanced protectiveness of the corrosion product layer.