Showing 2 results for Severe Plastic Deformation
S. Emami, T. Saeid,
Volume 6, Issue 1 (8-2020)
Abstract
Single phase brass strips with 2 mm thickness were severely deformed through 1 and 3 cycles of accumulative roll bonding process (ARB). ARB process effectively increased the hardness, yield strength, and the ultimate strength of the processed materials. The hardness of processed material increased from 95 HV in annealed material to 225 HV in 3 cycle ARBed material, and the yielding and ultimate strengths increased more than 5 and 2 times of the annealed sample, respectively. Friction stir welding (FSW) process was successfully conducted on the annealed and ARBed samples to investigate and compare the microstructure and the mechanical properties of the joints obtained in bead on plate configuration. Microstructural observations showed that very fine dynamically recrystallized grains developed in the stir zones (SZs) of all welded samples. Mechanical properties were evaluated by hardness and tensile testing. Hardness test for the ARBed and FS welded samples showed that the hardness value decreased by 110 Hv in the resultant SZs. Results of tensile testing revealed that yield and ultimate strength of the FS welded ARBed samples 1.3 and 1.8 times are greater than that of the annealed FS welded sample .
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.
