Study of the Contact Thermal Compression Behavior of Copper using Scanning Contact Potentiometry Method and Finite Element Analysis

Abstract

The issue of tracking residual stresses initiation in welding copper under various affected conditions is essential in increasing safety through improving the welding quality in particular, in the nuclear industry. This study investigated the behavior of welded copper numerically and experimentally under contact-heating compression test with constant clamping force. The scanning contact potentiometry (SCP) method was used to track the initiation and development of residual stresses within the weld zone. Furthermore, the finite element analysis (FEA) method was used to simulate and study the effect of thermal variations, with a constant compressive force, on mechanical factors that contribute to residual stresses formation within the weld zone. Additionally, scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to get further information about the topography and composition of the specimen's surface. SCP results show that residual stress initiated from within the volume after 200 °C, and with further oxidation, its formation began on the surface after 250 °C. Using the relationship between maximum values of linearized von Mises stresses and maximum values of ADS at high SLS = 4.523, it was found that residual stresses generation began after 150 °C within the weld zone, and thermal stresses linearly increase with temperature due to further thermal expansion, which is associated with variation in linearized von Mises stresses and ADS maximum values. Comparison between potentiograms after 300 °C and FEA results have shown that the distribution of von Mises stress, normal stress, and total deformation are matching those in the distribution of ADS and are localized within the weld zone.
 HIGHLIGHTS
 
 The behavior of welded copper under compression at medium-low temperature range
 Residual stresses detection at an early stage localized within weldment zone
 Residual stresses increase with increased oxidation at copper surface
 Matched the SCP Experimental and FEA simulation results
 
 GRAPHICAL ABSTRACT