Fast strength-ductility synergistically adjusting of cold spray additive manufactured Cu deposits via electric pulse processing

Electric Pulse Processing (EPP) treatment was innovatively introduced to optimize the strength and ductility of the CSAMed Cu deposits. The results show that EPP is an efficient and fast post-treatment to improve the strength and ductility (within tens of seconds). The larger the pulse current and number of pulses, the better the mechanical properties. Interestingly, this research found that when the heat input determined by pulse current and number of pulses exceeds a certain threshold (pulse current intensity is 2000 A, number of pulses is 10), increasing the number of repeat time could also effectively improve the mechanical properties. A tensile strength of 210 MPa and a ductility of 14.0% could be obtained with reasonable EPP parameters (pulse current intensity is 2000 A, number of pulses is 10, and repeat number is 2), which is similar to those of conventional annealing (e.g., tensile strength is 272 MPa, elongation is 28.3%). The microstructure evolution analysis shows that EPP can effectively improve the bonding quality between the deposited particles by recrystallization, promote grain growth and the formation of twins, which is the main reason for the improvement of mechanical properties.