AZ91镁合金搅拌摩擦加工后的组织与性能

Microstructure and Properties of Friction Stir-Processed AZ91 Magnesium Alloy

采用400rpm-100mm/min,800rpm-100mm/min,800rpm-200mm/min三种工艺参数对铸态AZ91镁合金进行搅拌摩擦加工(FSP)处理,并对合金加工前后的显微组织和拉伸性能及微观断裂机制进行分析。结果表明,经800rpm-100mm/min工艺FSP处理后,合金的显微组织明显细化,延伸率和抗拉强度显著提高,综合拉伸性能最好,且拉伸断口主要表现为韧性断裂的特征。这主要是由于在FSP过程中合金发生动态再结晶,使合金晶粒显著细化及粗大β相的溶解和破碎所致。

Friction stir processing was applied to AZ91 magnesium alloy with 3 different parameters：400rpm-100mm/min, 800rpm- 100mm/min, 800rpm-200mm/min. The microstructure, tensile properties and micro-fracture mechanism of the alloy were analyzed before and after processing. The results suggest that the friction stir processing at the parameter of 800rpm-100mm/min can cause apparent grain refinement, significant improvement in ductility and ultimate strength, best comprehensive tensile strength of the AZ91 alloy. moreover, the fracture of the alloy takes on a feature of toughness fracture. The improvement in microstructure and properties was due to the dynamic recrystallization during FSP, which refined the grains of the alloy efficiently, and the dissolution and brokenness of the β phase during FSP.