Zone Wise Properties of Friction Stir Welded Copper – Stainless Steel Joints Using Digital Image Correlation

Abstract

Recent developments in imaging non destructive evaluation techniques offer possibilities of quantitative measurement of strain localizations associated with plastic instabilities. Digital image correlation is a technique now being widely employed for studying the temporal strain evolution associated during tensile deformation. This work focuses on the application of digital image correlation to visualise the two dimensional strain evolutions in the weld zone, heat affected zone and the base metal during monotonic uniaxial tensile deformation of friction stir weld samples of copper – stainless steel. The results indicated that the Cu- Stainless steel weld interface exhibited a lower tensile strength compared to the other regions. The experimental observations are discussed in relation with the current theoretical understanding. The experiments also reveal the potential of advanced imaging NDE methods for providing better insights of the micro mechanisms of deformation and failure including local deformation characteristics of the material under study.

Microstructures and Properties of Copper to Stainless Steel Joints by Hybrid FSW

“…Despite of this, it is reported that, Cu-SS can be joined with the help of different techniques such as shielded metal arc welding (SMAW), Tungsten/metal gas suspended arc welding, brazing, laser beam welding (LBW), electron-beam welding (EBW), hot isostatic pressing (HIP), explosive welding (EW), friction stir welding (FSW), etc. [10][11][12][13][14][15][16][17][18][19][20][21][22][23]. The melting of the material causes various problems of solidification cracking, porosity, and residual stresses that triggering premature failure [10][11][12][13][14][15][16][17][18][19].…”

“…[10][11][12][13][14][15][16][17][18][19][20][21][22][23]. The melting of the material causes various problems of solidification cracking, porosity, and residual stresses that triggering premature failure [10][11][12][13][14][15][16][17][18][19]. Furthermore, LBW and EBW necessitate close control over the parameters which results in a higher degree of complexity [10][11][12][13][14][15][16][17][18][19].…”

“…The melting of the material causes various problems of solidification cracking, porosity, and residual stresses that triggering premature failure [10][11][12][13][14][15][16][17][18][19]. Furthermore, LBW and EBW necessitate close control over the parameters which results in a higher degree of complexity [10][11][12][13][14][15][16][17][18][19]. Solid-state welding process such as EW involves explosive materials, whereas HIP enforces repetitive heating and cooling cycles [10][11][12][13][14][15][16][17][18][19].…”

“…Furthermore, LBW and EBW necessitate close control over the parameters which results in a higher degree of complexity [10][11][12][13][14][15][16][17][18][19]. Solid-state welding process such as EW involves explosive materials, whereas HIP enforces repetitive heating and cooling cycles [10][11][12][13][14][15][16][17][18][19]. It restricts grain growth resulting in heterogeneous joint.…”

“…In view of above, the attempts to do the same are limited, especially when weldments consist of high melting point materials such as Cu and SS. Srinivas et al [19] have concluded that FSW is better than other welding processes for Cu-SS joints. Shen et al [18] have suggested that microcracks and Cu penetration in SS can be avoided through FSW compared to gas metal arc welding.…”