Material Interactions in a Novel Pinless Tool Approach to Friction Stir Spot Welding Thin Aluminum Sheet
Material Interactions in a Novel Pinless Tool Approach to Friction Stir Spot Welding Thin Aluminum Sheet
复制标题
DOI：
10.1007/s11661-010-0514-x
复制
发表时间：
2011-05-01
影响因子：
2.8
通讯作者：
Prangnell, Phil
中科院分区：
文献类型：
--
作者：
Bakavos, Dimitrios;Chen, Yingchun;Prangnell, Phil
在搅拌摩擦点焊（FSSW）中对探针或销的要求导致不期望的键孔和“钩挂”，这会影响断裂路径和焊接强度。此外，FSSW的全焊接周期通常比汽车工业的理想周期长，为2至5秒。这里，它表明，使用一种新的无销工具设计，它可以实现高搭接剪切强度（类似于3.4 kN）在薄铝板（类似于1毫米厚），焊接周期时间短（< 1秒）。几种技术已被利用来研究材料流动和焊缝形成的机制，在无针FSSW，包括高分辨率X射线断层扫描，以了解工具设计和焊接参数的作用。尽管无销工具的“简单”性质，但发现焊接区中的材料流动是令人惊讶的复杂的，并且受到工具上的表面特征的强烈影响，这大大增加了塑性区到底部片材中的渗透。由于快速的热循环和高水平的晶粒细化，焊缝区被发现开发一个更高的强度比母材与焊后自然时效后的热影响区（HAZ）的证据很少。
The requirement for a probe, or pin, in friction stir spot welding (FSSW) leads to an undesirable keyhole and "hooking," which can influence the fracture path and weld strength. Furthermore, the full weld cycle for FSSW is typically longer than ideal for the automotive industry, being 2 to 5 seconds. Here, it is shown that using a novel pinless tool design it is possible to achieve high lap shear strength (similar to 3.4 kN) in thin aluminum sheet (similar to 1 mm thick), with short weld cycle times (< 1 second). Several techniques have been exploited to study the material flow and mechanisms of weld formation in pinless FSSW, including high-resolution X-ray tomography, to understand the role of the tool design and weld parameters. Despite the "simple" nature of a pinless tool, material flow in the weld zone was found to be surprisingly complex and strongly influenced by surface features on the tool, which greatly increased the penetration of the plastic zone into the bottom sheet. Because of the rapid thermal cycle and high level of grain refinement, the weld zone was found to develop a higher strength than the parent material with little evidence of a heat affected zone (HAZ) after postweld natural aging.