Effects on the Surface Texture, Superplastic Forming, and Fatigue Performance of Titanium 6AL-4V Friction Stir Welds
Effects on the Surface Texture, Superplastic Forming, and Fatigue Performance of Titanium 6AL-4V Friction Stir Welds
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DOI：
10.1007/s11665-010-9614-4
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发表时间：
2010-03
影响因子：
2.3
通讯作者：
D. Sanders;M. Ramulu;P. Edwards;A. Cantrell
中科院分区：
文献类型：
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作者：
D. Sanders;M. Ramulu;P. Edwards;A. Cantrell
研究了搅拌摩擦焊 (FSW) 工艺的速度和进给对沿对接焊熔核顶部表面纹理的影响。测试使用标称厚度为 2.5 毫米的细晶粒（0.8-2 μm）钛合金 6Al-4V 进行。结果表明，沿焊缝顶面的销工具痕迹对焊接面板的超塑性成形 (SPF) 特性和疲劳性能非常不利。研究发现，FSW 后通过机加工顶部表面来去除痕迹可以消除 SPF 期间焊缝的主要撕裂，并且焊缝的大部分疲劳寿命也得到恢复。通过进一步开发 FSW 工艺参数，对焊熔核具有与母材板材相同的 SPF 特性。通过使用水冷销工具和其他冷却技术，人们相信，在 FSW 过程中，焊接区可以保持在 β 转变温度以下，从而能够形成与传统熔焊工艺相比，独特有利于超塑性行为的晶粒结构。
The speed and feed effects of the friction stir welding (FSW) process on the surface texture along the top of a butt welded nugget were studied. The tests were conducted using fine grain (0.8-2 μm) titanium alloy 6Al-4V with a nominal thickness of 2.5 mm. It was shown that the pin tool marks along the top surface of the weld can be highly detrimental to both the superplastic forming (SPF) characteristics and the fatigue performance of welded panels. Removing the marks by machining the top surface after FSW was found to eliminate the predominant tearing of the weld during SPF and most of the fatigue life of across the weld was also restored. Through additional development of the FSW process parameters, the butt welded nugget was made to have equivalent SPF characteristics as the parent sheet material. By using a water-cooled pin tool and other cooling techniques, it is believed that the weld zone can be kept below the beta transus temperature during FSW, which enables the formation of a grain structure that is uniquely conducive to superplastic behavior, when compared to conventional fusion welding processes.