电弧超声对 316L 不锈钢 TIG 焊缝成形、组织及性能的影响

TIG welding is commonly employed for joining 316L stainless steel, with pulsed TIG welding enabling precise control of heat input and improved weld bead formation. However, the effects of pulsed TIG welding on melt pool agitation and microstructural refinement remain limited. To further enhance the weld microstructure and performance, arc-ultrasonic coupled pulsed TIG welding is adopted to investigate the influence and interaction mechanisms of arc-ultrasonic coupling on weld bead formation, microstructure, and properties of 316L stainless steel. Weld bead formation, microstructure, tensile properties, and corrosion resistance are systematically compared under different arc ultrasonic parameters. The application of arc ultrasonic energy is found to significantly improve weld bead formation, refine the microstructure, and enhance the comprehensive properties of the weld metal. Variations in ultrasonic current amplitude produce noticeable improvements in weld area, joint ductility, and corrosion resistance, while the tensile strength remains largely unaffected. At appropriate ultrasonic current frequencies, acoustic streaming and ultrasonic cavitation induce vigorous flow within the molten pool, promoting a more uniform distribution of solutes and thermal energy. These effects contribute positively to weld bead morphology, microstructural homogeneity, and mechanical performance. Furthermore, corrosion resistance is improved under certain ultrasonic frequencies. Intermittent ultrasonic application results in superior weld bead formation compared to both the non-ultrasonic and continuously applied ultrasonic conditions. Euler buckled beam formed negative stiffness mechanism is proposed and the static characteristic of which is analyzed. A quasi-zero stiffness isolator is designed by parallel connected the negative stiffness mechanism and a linear isolator. The Euler buckled beam structure functions as a stiffness corrector to lower the stiffness of the linear isolator. If the load is chosen properly, the equilibrium point will be set at the zero stiffness point, any changes of the load will lead the equilibrium point deviating from the zero stiffness point. The dynamic model is built considering the load effect and the Harmonic balance method is employed to solve for the dynamic response of the system. Force transmissibility of the zero stiffness isolator is defined and compared with that of an equivalent linear one. The effect of excitation amplitude and load on the performance is analyzed. The results show that the force excitation amplitude and load can change the characteristic of the nonlinear isolator from a hardening stiffness system to a softening stiffness system and even a mixed softening-hardening stiffness system. The excitation amplitude and load also have great affection on the transmissibility performance.