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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。
The microstructure evolution and fracture change of AZ31 magnesium alloy were studied. Texture measurement by neutron diffractometer. The microstructure and fracture morphology of stress corrosion cracking (SCC) specimens were observed by light microscopy and scanning electron microscopy. Fracture Surface Structure of SCC Samples Studied by X - ray Diffraction. The results show that the surface of the base material formed a significant basal texture. However, basal plane rotation occurred in the agitating zone grains, and most of the grained grains were inclined at 25 ° along the welding direction. Under slow tensile stress, feathery twins and hydrides form in air and aggressive solutions, respectively. In solution, the transgranular crack propagates, eventually breaking on the turning side. Hydrides present on the fracture surface suggest that there may be hydrogen-induced delayed cracking mechanisms in stress corrosion of magnesium alloys.