10mm厚LF2铝合金搅拌摩擦焊温度分布及组织分析

Analysis on Temperature Distribution and Microstructure of Friction Stir Welding for 10mm LF2 Aluminum Alloy Plate

采用嵌入热电偶测温法得到了10mm厚LF2铝合金搅拌摩擦对焊时不同深度(2、5和8mm)、距离搅拌针不同位置的FSW温度分布;通过对焊缝不同位置的金相观察,分析了温度场对10mmLF2搅拌摩擦焊焊缝金属组织的影响。实验结果表明,返回侧温度略高于前进侧,但最大不超过40℃;焊缝顶部的最高温度出现在与轴肩接触的边缘区域,而焊缝底部的最高温度出现在搅拌针边缘;同时焊缝底部出现的"鼓"形组织表明焊缝不同深度的温度分布不仅与热源产热量有关,还与材料的流动情况有关。

The thermal history and evolution were obtained by embedding thermal couples at specific locations for the 10mm LF2 aluminum alloy during the FSW butt welding. The temperature distribution feature in different depth（2,5, 8mm） from the top, and different distance from the pin was found. The effect of temperature on microstructure was analyzed by observing its metallic phase. The results show that the temperature of retreating side is higher than advancing side,but less than 40℃ ; the maximum temperature of top locates at the shoulder margin, and that of bottem locates at the pin round. Meanwhile, from the ＂ drum＂ zone of welded seam, it can be concluded that the temperature distribution of different depth is related to the thermal source and the flow pattern of materials.