The microstructures, mechanical properties and corrosion behaviors of the ultra-high strength Al–Zn–Mg–Cu-Sc aluminum alloy fabricated by wire-arc additive manufacturing process using a self-prepared 7B55-Sc filler wire were systematically investigated under different heat treatments. The results showed that the microstructures of the as-deposited, T6, T73, and retrogression and re-aging (RRA) heat treatments were all composed of fine equiaxed grains with a size of about 6.0 μm. The grain boundary precipitates (GBPs) of the as-deposited sample were very coarse and continuously distributed along the grain boundaries, and the intragranular precipitates (IGPs) mainly consisted of a small amount of ηMg(Zn,Cu,Al)2 and η′ phases. After T6 heat treatment, the GBPs became much finer, but still continuously distributed along the grain boundaries. The IGPs mainly consisted of fine GP zones and η′ phases. After RRA heat treatment, the GBPs became coarser and discontinuously distribu
In this study, the corrosion properties of Ti-6Al-4 V alloys using wire-arc Directed Energy Deposition (DED) with and without different Magnetic Arc Oscillation (MAO) patterns are comparatively evaluated. The relationship between corrosion resistance and microstructural features including grain size, geometrically necessary dislocation (GND), and grain orientation spread (GOS) of as-fabricated specimens are fully explored. The results show that magnetic arc oscillation, including liner arc oscillation and arc rotation, can enhance corrosion stability of as-fabricated Ti-6Al-4 V alloys. This enhanced corrosion stability is due to refined α grains, increased grain boundaries and enhanced dislocation density that provides more active reaction sites which, when coupled with adequate ion diffusion, expedites passive film growth on the Ti-6Al-4 V metal surface. Moreover, a transpassive film was directly observed on the Ti-6Al-4 V corrosive surface, and was confirmed to contain non-stoichiom
This work utilizes wet–dry cycle corrosion tests to investigate the corrosion behavior of medium manganese steel by analyzing its corrosion kinetics, corrosion phases, surface morphology, cross-section morphology, elemental distribution and electrochemical characteristics. The corrosion process was divided into two stages, and the change is due to the unique transformation of corrosion products. The mixture of β-FeOOH and MnO2 in the corrosion product up to 72 h causes an increase in redox ability and electronic transmission rate and enlarges the specific surface in the initial corrosion products. The transformation of the unique mixture determines the transformation of the corrosion process.
To further improve the comprehensive service performance of Zn, hot extrusion combined multi-pass equal channel angular pressing route were applied to process Zn-1(wt%)Mg alloy and 1(vol%)β-TCP/Zn-1Mg composites. As-cast cylinders specimens with a diameter of 60 mm were finally processed to the ECAP-processed specimens with the dimensions of 15 mm × 15 mm × 120 mm. The evolution and corresponding mechanism of the microstructure, mechanical properties, corrosion behavior, and biocompatibility of 1β-TCP/Zn-1Mg composites and Zn-1Mg components were systematically investigated. As a result, compared with Zn-1Mg alloy, the grain refinement effect of ECAP was enhanced in the 1β-TCP/Zn-1Mg composites with exact the same ECAP conditions. Among all the experimental specimens, the minimum average grain size of 3.0 ± 0.3 µm was achieved in 1β-TCP/Zn-1Mg composites processed by 8 ECAP passes. With the increase of ECAP processing times, the texture strength increased, and the texture direct
In a recent study published in the journal Materials, researchers from Poland analyzed casein as a potential coating material to prevent corrosion of magnesium (Mg)-based alloys when used in orthopedic implants.