The influences of different laser power density in LSP (laser shock peening) on the corrosion performance of biocompatible magnesium alloy ZK60 were researched via SBF (Simulated Body Fliud) immersion testing and electrochemical testing. Corrosion morphology and corrosion products were observed and analyzed using SEM (Scanning Electron Microscope) outfitted with EDS (Energy Dispersive Spectrometer) and XRD (X-ray Diffraction). Simultaneously, 3D morphology, surface roughness, residual stress, and microstructure were also characterized. Results reveal that the modified samples can obtain higher residual compressive stress, which can lead to lower degradation rates in SBF solution. In terms of the weight loss of the samples, corrosion resistance increased by 52.1% maximally. The corrosion potential of modified samples in the SBF solution positively shifted from −1.3884 V to −1.1094 V and the corrosion current density decreased by 13.2% at most. The anti-corrosion ability of ZK60 is significantly enhanced by the LSP process.
The surface of the aluminum alloy is prone to oxidation, which in turn affects the quality of the weld. The 5A12 aluminum alloy was cleaned by acousto-optic Q-switched diode-pumped Nd:YAG laser and the effects of different laser powers and different cleaning speeds on the surface roughness, microstructure, element content, microhardness, residual stress and corrosion resistance of aluminum alloy were investigated. The results show that when the power is 98W and the cleaning speed is 4.1 mm/s, the effect of Nd: YAG laser on the removal of oxide film on 5A12 aluminum alloy surface is the most effective. After laser cleaning, the smoothness and strength of aluminum alloy surface can be effectively improved. However, as a major element in 5A12 aluminum alloy, the content of magnesium decreased. At the same time, the residual tensile stress was generated on the surface of the aluminum alloy after cleaning, and the corrosion resistance slightly decreased.
With high polymer added into suspension, the use of abrasive slurry jet (ASJ) has significant advantages in energy management. The quality and efficiency of ASJ are affected distinctly by its structure and the flow field feature, both of which depend on the rheological properties of the abrasive slurry. Therefore, this paper carries out a series of experiments to study the rheological properties of abrasive slurry with polyacrylamide (PAM) and carboxy methyl cellulose (CMC) commonly used in ASJ. The paper also explores the effect of temperature and abrasive on the apparent viscosity of the abrasive slurry. Experimental results show that PAM and CMC solutions behave as a pseudoplastic non-Newtonian fluid in the selected concentration range, whose apparent viscosity increases with the concentration. In addition, specific non-Newtonian fluid constitutive equations of the power-law model for PAM and CMC solution were obtained by nonlinear fitting calculation. The apparent viscosity decreases with the growth of temperature because it leads to the increase in spacing between molecules, making the attraction between molecules smaller and smaller. However, the abrasive has no influence on the apparent viscosity of abrasive slurry for these molecular bonds, and their mechanical entanglements are not destroyed by abrasive particles in the suspension.
This paper presents a new method of postweld treatment. The 5154 aluminum alloy was cleaned by Nd:YAG laser after welding. The surface morphology, energy spectrum, friction and wear properties, hardness, and residual stress of the welded joint at different cleaning speeds were studied. The results show that an Nd:YAG laser can effectively remove the welding slag and eliminate the pores in the weld under a certain cleaning speed. When the cleaning speed is in the range of 5.2–20.7 mm/s, laser cleaning can improve the heat-affected zone’s tribological characteristics. Laser cleaning can eliminate the residual stress of the welded joint and improve the welding joint’s strength, which provides a reference for laser cleaning instead of traditional heat treatment.
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