AZ31镁合金摩擦搅拌焊在慢拉伸应力腐蚀过程中的组织演化和氢致延迟开裂(英文)

研究AZ31镁合金摩擦搅拌焊组织的演化,包括织构和断口变化。利用中子衍射仪测量织构。利用光学显微镜和扫描电子显微镜观察应力腐蚀开裂(SCC)样品的金相及断口形貌。利用X射线衍射仪研究SCC样品的断口表面结构。结果表明,在母材表面形成了明显的基面织构。然而,搅拌区晶粒发生了基面旋转,大多数晶粒的基面沿着焊接方向倾斜25°。在慢拉伸应力作用下,在空气和侵蚀性溶液中分别形成了羽毛状孪晶和氢化物。在溶液中,穿晶裂纹扩展,最终断裂在回转侧。在断口表面存在的氢化物表明镁合金应力腐蚀可能存在氢致延迟开裂机制。

Nafion/polypyrrole and Nafion/DMSO Organic Coatings for Magnesium Protection

Nafion/polypyrrole and Nafion/Dimethysulfoxid （DMSO） organic coatings were prepared on the surface of pure magnesium by simple immersion and heat treatment. The morphologies and corrosion resistance of the organic coatings were investigated by using optical microscopy and electrochemical corrosion testing, respectively. It is shown that Nafion/polypyrrole organic coatings resulted in the corrosion resistance of magnesium decreasing; while Nafion/DMSO organic coatings can effectively improve the corrosion resistance of magnesium. Also, the corrosion resistance increased with the thickness of the Nafion/DMSO organic coating increased.