A model of material flow during friction stir welding
A model of material flow during friction stir welding
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DOI：
10.1016/j.matchar.2007.10.002
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发表时间：
2008-09-01
影响因子：
4.7
通讯作者：
Blicharski, Marek
中科院分区：
文献类型：
--
作者：
Hamilton, Carter;Dymek, Stanislaw;Blicharski, Marek
镀锡的6061-T6铝合金挤压件采用搅拌摩擦焊，采用90对焊结构。焊核是由富颗粒材料和贫颗粒材料交错排列而成的带状组织。扫描和透射电子显微镜显示富颗粒带中存在大量的TiN，但从TMAZ、HAZ和基材中获得的TEM箔没有显示出含锡的相。由于TiN局限于焊前挤压件的表面，表面材料流入熔核区域，形成富颗粒条带。类似地，不含TiN的贫粒带起源于挤压件厚度内。提出了搅拌摩擦焊焊接过程中的材料流动模型，在该模型中，当表面材料从后退一侧挤压到搅拌摩擦焊销周围的塑化区时，会形成焊核。挤压柱在推动材料进入该区域的挤压力和抵抗其进入的原位材料的拖拉力之间发生屈曲。因此，形成了交错的表面材料和原位材料的带状微结构。该模型成功地描述了几个实验观察到的焊缝特征，但该模型仅限于特定的材料流动条件和关于稳态的假设。(C)2007 Elsevier Inc.保留所有权利。
Tin plated 6061-T6 aluminum extrusions were friction stir welded in a 90 butt-weld configuration. A banded microstructure of interleaved layers of particle-rich and particle-poor material comprised the weld nugget. Scanning and transmission electron microscopy revealed the strong presence of tin within the particle-rich bands, but TEM foils taken from the TMAZ, HAZ and base material showed no indication of Sn-containing phases. Since tin is limited to the surface of the pre-weld extrusions, surface material flowed into the nugget region, forming the particle-rich bands. Similarly, the particle-poor bands with no tin originated from within the thickness of the extrusions. A model of material flow during friction stir welding is proposed for which the weld nugget forms as surface material extrudes from the retreating side into a plasticized zone surrounding the FSW pin. The extruded column buckles between the extrusion force driving the material into the zone and the drag force of the in-situ material resisting its entry. A banded microstructure of interleaved surface material and in-situ material, therefore, develops. The model successfully describes several of the experimentally observed weld characteristics, but the model is limited to specific conditions of material flow and assumptions regarding steady-state. (C) 2007 Elsevier Inc. All rights reserved.