Homan Nikbakht1, Mohammadreza Khanzadeh, Hamid Bakhtiari,
Volume 7, Issue 2 (1-2022)
Abstract
In the present study, the corrosion behavior and microstructural changes of 5000 series aluminum and copper sheets after the explosive welding process have been investigated. Explosive welding is performed with a fixed stop interval and change of explosive load. Dynamic potential polarization tests and electrochemical impedance spectroscopy, light microscopy, and scanning electron microscopy were used. The results of TOEFL polarization curves show that the lowest corrosion velocity was related to the sample with an explosive load of 1.5 and the highest corrosion velocity was related to the sample with an explosive load of 2.5. The corrosion resistance of a sample with an explosive load of 2.5 is less than that of a sample with an explosive load of 1.5 due to more severe plastic deformation at the joint. The metallographic results show a wave-vortexing of the joint due to the increase in the explosive charge. The results of the impedance test in welded samples showed that the value of n (experimental power parameter) decreased with wave-vortexing of the joint and the sample with 2.5 explosive load had the highest corrosion rate. Based on the results of scanning electron microscopy, it was observed that with an increasing explosive charge, the thickness of the local melting layer gradually increases.
Gh. Khalaj, A. Fadaei,
Volume 9, Issue 1 (5-2023)
Abstract
In this research, the effect of post weld heat treatment on the microstructure and mechanical properties of the three-layer explosion welding joint of austenitic steel 321-aluminum 1050-aluminum 5083 was investigated. The welded samples were heat treated at 250 and 350°C for 10000 seconds. The structure and properties were investigated using optical microscope, scanning electron microscope, microhardness measurement and shear-compressive strength. The results showed that in all conditions, the interface of aluminum 5083-aluminum 1050 was smooth and with complete continuity; However, the interface between stainless steel 321 and aluminum 1050 had a reaction layer with variable and discontinuous thickness. During the heat treatment, the thickness of the interface layer increases according to the diffusion kinetics and reaches 18.6 microns in the maximum value. With the increase of heat treatment temperature, the average concentration of aluminum in the reaction layer of the interface increased from 85% to more than 90%, but the concentration of iron decreased from 10% to less than 5%. Also, shear-compressive strength decreases from 94.6 to 56.7 MPa.
