强制冷却搅拌摩擦加工2024铝合金的组织性能研究

Microstructure and Properties of Forced Cooling Friction Stir Processed 2024 Aluminum Alloy

摘要:

在强制冷却条件下对2024-T4铝合金板进行搅拌摩擦加工，分析了各区(母材区、热机影响区、搅拌区)的组织形貌特征，并研究了前进速度对加工区组织性能的影响。结果表明，从母材、热机影响区到搅拌区晶粒逐渐减小，搅拌区为均匀细小的再结晶组织，平均晶粒尺寸达1.9 μm；母材大部分为大角度晶界，热机影响区主要为小角度晶界，搅拌区取向差分布呈双峰模态。搅拌区硬度和抗拉强度随前进速度增大而增大

Abstract:

Friction stir processing was applied to 2024-T4 aluminum alloy plate under the condition of forced cooling. The microstructure of each zone (the base metal, the thermo-mechanically affected zone, the stir zone) and the effect of the advancing speed on the mechanical properties of the stir zone were studied. The results show that the grain size decreases gradually from the base metal, through the thermo-mechanically affected zone, to the stir zone. The microstructure in the stir zone is significantly refined and the grains are distributed uniformly with an average size of 1.9 μm. The base metal exhibits a large number of high-angle grain boundaries, while the thermo-mechanically affected zone has numerous low-angle grain boundaries. The distribution of misorientation angle in the stir zone presents a bimodal phenomenon. Hardness and tensile strength of the stir zone are increased with higher advancing speed