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The influence of room temperature (RT) and cryogenic temperature (CR) supersonic fine particle bombardment (SFPB) on the surface, microstructure, and mechanical properties of Fe–28Mn–8Al–1C lightweight steel is investigated in this work. The results indicate that both RT‐SFPB and CR‐SFPB successfully induce gradient nanostructures on the surface of steel, refining the grains to the nanoscale. Furthermore, CR‐SFPB results in a finer grain size and higher dislocation density compared to RT‐SFPB. Additionally, the dominant deformation mechanism shifts from dislocation slip for RT‐SFPB to a combination of dislocation slip and twinning for CR‐SFPB. CR‐SFPB is seen to be superior to RT‐SFPB in terms of surface integrity and strength due to low‐temperature lubrication effect, suppression of dynamic recovery and reduced stacking fault energy of the material. Interestingly, while CR‐SFPB enhances strength, elongation remains comparable to that of untreated material. However, excessive impact times during SFPB treatment promote microcrack formation on the surface, compromising plasticity. [ABSTRACT FROM AUTHOR]

To cope with harsh working conditions, new corrosion-resistant coated steel wires with higher tensile strength have been developed. This study investigates the corrosion characteristics of a new zinc–aluminum alloy-coated steel wire under stress conditions. The particulate corrosion products generated by the oxidation of the coating in the initial stage of corrosion are converted into layer-structured corrosion products at the early stage of corrosion. Moreover, high-stress conditions have a significant influence on the critical conversion time from the coating corrosion stage to the iron matrix corrosion stage. Thus, the uniform corrosion depth (i.e., the mass loss rate) could be fitted with a continuous power function model rather than the previously used two-stage model owing to an ambiguous moment of conversion under stress conditions. The pitting corrosion depth could be fitted with a lognormal distribution in this study. The probability distributions for the aspect ratios of corrosion pits under different stress conditions tended to be consistent. Finally, the block's maximum pitting factor followed a Gumbel distribution with a scale parameter that changed linearly with the stress level and a location parameter related to the square of the stress level. [ABSTRACT FROM AUTHOR]

The effect of tempering temperature on the microstructure and intergranular corrosion property of 2205 duplex stainless steel (DSS2205) was determined using a boiling acid intergranular corrosion test (boiling 65% nitric acid and 50% sulfuric acid–ferric sulfate), an optical microscope, a transmission electron microscope, and a double-loop electrochemical potentiokinetic reactivation (DL-EPR) test. The results show that the ferrite content of the DSS2205 is about 50% in a specimen close to a solid solution state (1050 °C for 1 h, then water-quenched) when tempered at 675 °C–725 °C for 1 h. As the tempering temperature rises to 750 °C–800 °C for 1 h, the ferrite content drops gradually from 49% to 35%. M23C6, FeCr (σ phase), and Cr2N phases are precipitated when the specimen is tempered at 675°C–800 °C for 1 h. When the tempering temperature rises to 750 °C–800 °C for 1 h, the content and size of σ phase increase significantly. In the boiling acid intergranular corrosion test, when the specimen is tempered at 675 °C–725 °C for 1 h, the corrosion rate is higher than when it is tempered at 750 °C–800 °C for 1 h. In the DL-EPR test, when the specimen is tempered at 675 °C–800 °C for 1 h, the intergranular corrosion sensitivity rises gradually. External polarization is added during the DL-EPR test, and the test principle is different from that of the boiling acid intergranular corrosion test, resulting in a different sensitivity to intergranular corrosion compared to boiling acid intergranular corrosion. [ABSTRACT FROM AUTHOR]

The fatigue fracture and microstructure near the fatigue fracture of TC11 titanium alloy after high cycle fatigue were analyzed by means of optical microscope (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the fatigue fracture under different loads is composed of fatigue source area, crack propagation area and transient breaking area. Meanwhile, there are large amounts of secondary cracks perpendicular to propagation directions of the fatigue crack. With the load increasing, the number of secondary cracks and the width of the cracks increase, as well as the width of fatigue striations. When the load is from 475 MPa to 525 MPa, the width of fatigue striations increases from 0.6 µm to 1 µm. Under alternating load, a large number of dislocation substructures are emerged in titanium alloy, and high density dislocation pile-up lies in the interface of α and β, leading to the stress concentration. Finally, the crack source is formed and the fatigue life is reduced. [ABSTRACT FROM AUTHOR]