轧制温度对ZK60镁合金腐蚀性能的影响

    Effect of Rolling Temperature on Corrosion Properties of ZK60 Magnesium Alloy

    • 摘要: 将挤压态ZK60镁合金在400℃固溶24 h,然后进行不同温度的轧制处理。分别采用析氢法、失重法、电化学测试法研究ZK60、固溶态及不同温度下轧制态镁合金的腐蚀性能。利用光学显微镜与扫描电镜对合金组织、腐蚀产物和腐蚀形貌进行观察,并使用能谱和XRD对其进行物相分析。结果表明:轧制是以动态再结晶的方式来细化晶粒,进而改善合金的耐腐蚀性能。合金中的晶粒大小,晶界分布及析出第二相的数量是影响合金耐蚀性的主要因素。随着轧制温度的升高,再结晶晶粒逐渐长大,晶粒尺寸逐渐变大,析出的第二相也逐渐变多,降低了合金的耐蚀性能。在175℃轧制后的合金平均晶粒尺寸最小,晶界分布均匀,耐腐蚀性能最好。

       

      Abstract: The extruded ZK60 magnesium alloy was dissolved at 400 ℃ for 24 h, and then rolled at different temperatures. The corrosion properties of ZK60, solid solution and rolled magnesium alloys at different temperatures were studied by hydrogen evolution method, weight loss method and electrochemical test method. The microstructure, corrosion products and corrosion morphology of the alloy were observed by optical microscope and scanning electron microscope, and its phase was analyzed by energy spectrum and XRD. The results show that the rolling refines the grains by dynamic recrystallization, thus improving the corrosion resistance of the alloy. The grain size, grain boundary distribution and the number of precipitated second phase in the alloy are the main factors affecting the corrosion resistance of the alloy. With the increase of rolling temperature, the recrystallized grains gradually grow, and the precipitated second phase gradually increases, which reduces the corrosion resistance of the alloy. The alloy rolled at 175 ℃ has the smallest average grain size, uniform grain boundary distribution and the best corrosion resistance.

       

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