氧化镁表面膜对粉末冶金镁合金影响作用的研究进展

Research Progress on the Effect of MgO Surface Film on Powder Metallurgical Mg Alloy

镁粉末易氧化,生成的表面氧化膜影响粉末粒子间的结合,因而镁合金粉末冶金通常在真空或惰性气体保护下进行。如果在粉末冶金过程中,利用球磨和强烈塑性变形,使表面氧化膜破碎成细小的亚微米甚至纳米超细粒子,并均匀分布,则有可能使氧化镁成为弥散增强相而起到强化镁合金的作用。分析了常规粉末冶金法制备镁合金存在的问题,探讨了粉末热挤压法制备高性能镁合金的优势,综述了表面氧化膜对粉末冶金镁合金的影响作用,指出对镁粉末表面氧化膜作用再认识的重要性与必要性。

Magnesium powders are easy to be oxidized,and the resultant surface oxide films hinder bonding of the powders,therefore the magnesium powder.metallurgy has to be conducted in vacum or shielded gas atmosphere.Whereas,if the surface oxide film can be broken into fine submicron or even nanometer ultrafine particles by ball milling and severe plastic deformation,and evenly distributed in the process of powder metallurgy,it is possible to make the magnesium oxide particles become a dispersive enhancement phase and play a role in strengthening the magnesium alloy.The problems existing in the conventional powder metallurgy method for preparing magnesium alloys were analyzed,and the advantages of hot extrusion method for preparing high peformance magnesium alloys were discussed.The effect of suface oxide film on powder metallurgy magnesium alloys was summarized,and the importance and necessity of reunderstanding the efct of surface oxide film on magnesium powder was pointed out.