摘要
The influence of R/v ratio on joint quality in 2024-T351 aluminum alloy was studied. Specimens were subjected to friction stir welding with the rotation rates of 750, 950 and 1180 r/min and welding speed between 73 and 190 mm/min, providing R/v ratio between 5.00 and 10.27. The welded joints were tested by means of both non-destructive （visual, penetrant and X-ray inspection） and destructive （metallographic, tension and hardness） testing. In all specimens typical zones are revealed, with corresponding differences in grain size. Tensile efficiency of the joints obtained is in the range of 52.2%to 82.3%. The results show that the best quality is obtained at R/v ratio of 8.06, 10.17 and 10.27. This behavior is attributed to the assumption that the material flows around the pin with an optimal speed, i.e. sufficient amount of material is available to fill the gap and prevent tunnel formation. R/v ratio also showed influence on hardness distribution, onion features and crack initiation/propagation zones.
研究搅拌摩擦焊时R/v比对2024-T351铝合金焊接质量的影响。搅拌摩擦焊时搅拌针的旋转速度设定为750、950和1180 r/min，焊接速度在73~190 mm/min内变化，对应的R/v比在5.00~10.27内。采用各种无损（外观检测、X射线检测）和有损（金相观察、拉伸实验和硬度测量）检测手段对焊接试样进行分析。在所有的试样中，搅拌摩擦焊中各种典型的区域都有存在，不同的区域其晶粒尺寸不同。接头的拉伸性能为基材的52.2%~82.3%。在R/v比为8.06，10.17和10.27时焊接质量最佳。其原因是在最佳搅拌速度下，材料围绕搅拌针充分流动，从而能够填充其中产生的空隙，阻止空洞的生成。结果还表明，R/v 比对接头的硬度分布、洋葱样形状、裂纹的萌生和扩展都有影响。
基金
Ministry of Education and Science of Serbia for financial support through Project TR34018
