搅拌摩擦加工对AZ91镁合金微观组织及裂纹扩展性能的影响

Effect of Friction Stirring on Microstructure and Crack Propagation Properties of AZ91 Magnesium Alloy

对铸态AZ91镁合金进行搅拌摩擦加工,通过光学显微镜,扫描电镜进行组织及断口分析。结果表明,观察发现晶粒得到极大细化,第二相融入基体。对其裂纹扩展行为研究发现,抵抗裂纹扩展能力提高,加工之后的裂纹扩展断口出现韧窝,相比母材呈现塑性断裂的特征,发生脆韧转变。

The as-cast AZ91 magnesium alloy was prepared by friction stir processing, and the microstructure and fracture were analyzed by optical microscopy and scanning electron microscopy. The results show that the grains are greatly refined and the second phase is incorporated into the matrix. It is found from the study of crack propagation behavior that, with the improvement of crack propagation resistance, dimples appear at the crack propagation fracture after processing, and the brittle and ductile transition occurs compared with the plastic fracture characteristic of the base materials.