Showing 4 results for Explosive Welding
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.
Gh. Khalaj, J. Khalaj, F. Soleymani,
Volume 10, Issue 1 (6-2024)
Abstract
In this study, the microstructure of the joint interface in three-layer explosive welding of austenitic stainless steel 321 - aluminum 1050 - aluminum 5083 was examined before and after heat treatment. The welded samples were subjected to heat treatment at temperatures of 250°C and 350°C for durations of 1000, 3000, and 10000 seconds. Microstructural analysis was performed using optical microscopy and scanning electron microscopy. The results revealed that under all conditions, the Joint Interface of aluminum 5083 - aluminum 1050 exhibited a flat and defect-free structure. With increasing standoff distance, the Joint Interface of stainless steel 321 - aluminum 1050 transitioned from a smooth to a wavy pattern, and the average layer thickness increased from 4.95 μm to 6.7 μm. During heat treatment, the layer thickness in the Joint Interface increased proportionally to the diffusion kinetics, reaching maximum values of 18.56 μm and 15.02 μm for samples with standoff distances of 6.75 mm and 6 mm, respectively. The activation energies for diffusion were calculated as 46.6 kJ/mol and 42.4 kJ/mol, and the diffusion constants were 142.2 ms-1 and 45.3 ms-1 for the same samples.
E. Mohammadi, S. A. A. Akbari Mousavi,
Volume 12, Issue 1 (5-2026)
Abstract
In this study, the metallurgical and mechanical properties of the interface obtained by explosive welding of 8-92 phosphor bronze to St37 carbon steel were investigated. The effects of explosive welding parameters such as explosive charge amount and stand-off distance on the shape and microstructure of the interface, mechanical properties and corrosion behavior were investigated. The results showed that with increasing stand-off distance and explosive charge amount, the velocity and angle of impact increased, and this phenomenon led to the interface transforming from a smooth to a wavy state and resulting in melted and separated regions. The results obtained from scanning electron microscope (SEM) images showed that with increasing stand-off distance and explosive charge amount and consequently increasing impact velocity, the length and height of the waves created at the interface increased. Energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis showed that no intermetallic compounds were formed at the joint interface. The results of the microhardness test also indicated that the hardness around the joint interface increased by 25% due to plastic deformation and work hardening caused by the intense impact of the base and flying plates. By performing shear strength tests, it was found that in all samples, failure occurred in the phosohor bronze layer and no failure occurred due to separation of the samples from the interface. By performing tensile tests, it was found that the ultimate tensile strength increased from 430 to 488 MPa with increasing stand-off distance and explosive load. Polarization acquisition and impedance spectroscopy (EIS) tests showed that with increasing impact energy, the corrosion potential decreased and the corrosion current density increased significantly from 5.5 to 13.2 μA/cm2.
