铝合金搅拌摩擦焊接头行为分析

Characterizations of Friction Stir Welding on Aluminum Alloy

关键词:  搅拌摩擦焊  焊接  铝合金  流变

Key words:  friction stir welding  welding  aluminum alloy  flow

摘要:

详细介绍了搅拌摩擦焊(FSW)接头塑性流变数值模拟所得到的结果,并且利用搅拌摩擦焊的"插入试验",测量了搅拌头旋转着插入铝合金材料过程中作用在搅拌头上的作用力,并将之转化为有效的粘度值和温度输出,确定了搅拌摩擦焊过程中充分塑化区(FPZ)的材料粘性。3-D数值模拟结果显示了搅拌头肩台下大约1.5mm的紊流区域的形成;解释了在异种金属搅拌摩擦焊焊接过程中无序混合产生的间混薄层结构,以及局部液相形成(初始熔化)引起的搅拌头的瞬间滑移导致了在特定的温度下(Tcrit)的材料粘性迟滞。

Abstract:

The results produced during fluid flow modeling of friction stir welding are described.The viscosity of material in the fully-plasticized region is determined using plunge testing,where the forces that acting on a rotating steel pin as it penetrates the aluminum alloy base material are measured and converted into effective viscosities and temperature output.3-D modeling results show the formation of a chaotic flow zone about 1.5 mm below the tool shoulder.It is suggested that chaotic mixing produces the intermingled lamellae formed in dissimilar FSW welds.Also,transient tool slipp age produced by local liquid formation results in hysteresis in the viscosity/shear stress plane at a critical temperature Tcrit.