This study aimed to investigate the impact of corrosion on the microstructure and tensile properties of 7075 high-strength alloy. It involved outdoor exposure tests in an actual marine atmospheric environment in Wanning, Hainan Province. The results showed that the 7075 alloy was corroded rapidly in the marine atmospheric environment, and corrosion pits and intergranular cracks were generated. The intergranular cracks were extended along the grain boundary during corrosion, leading to the exfoliation of the matrix. The cause for the intergranular corrosion was discussed based on the microstructure characteristics of 7075 alloy. The tensile properties of the 7075 alloy gradually deteriorated with the increase of exposure time in the marine atmospheric environment. The ultimate strength and elongation were decreased by about 3.2% and 58.3%, respectively, after 12 months of outdoor exposure.

This work analyzed changes in the corrosion morphology and mechanical performance of 7085 aluminum alloy after outdoor exposures for different times in a humid and hot marine atmospheric environment. After one month of exposure, a pronounced corrosion of the alloy was observed. The corrosion product was mainly Al(OH)₃, and the corrosion features were mainly pitting corrosion and intergranular corrosion (IGC). With the exposure time extended from 6 months to 12 months, the IGC depth increased from 114 μm to 190 μm. After a 1-year outdoor exposure in a humid and hot marine environment, the alloy’s ultimate strength and yield stress remained nearly unchanged, while its elongation and area reduction decreased from the original 6% and 9%, respectively, to 3% and 5%. Moreover, the reasons for IGC and its effect on the mechanical performance was analyzed.

The formation and evolution of shear bands in Inconel 718 nickel-base superalloy under plane strain compression was investigated in the present work. It is found that the propagation of shear bands under plane strain compression is more intense in comparison with conventional uniaxial compression. The morphology of shear bands was identified to generally fall into two categories: in “S” shape at severe conditions (low temperatures and high strain rates) and “X” shape at mild conditions (high temperatures and low strain rates). However, uniform deformation at the mesoscale without shear bands was also obtained by compressing at 1050 °C/0.001 s⁻¹. By using the finite element method (FEM), the formation mechanism of the shear bands in the present study was explored for the special deformation mode of plane strain compression. Furthermore, the effect of processing parameters, i.e., strain rate and temperature, on the morphology and evolution of shear bands was discussed following a phenomenological approach. The plane strain compression attempt in the present work yields important information for processing parameters optimization and failure prediction under plane strain loading conditions of the Inconel 718 superalloy.

Actual marine atmospheric pre-corrosion behavior and its effect on the fatigue performance of 7075-T73 aluminum alloy were studied by means of marine atmospheric outdoor exposure testing and fatigue testing. The surface and cross-sectional microstructures of aluminum alloy specimens after different numbers of days of exposure were analyzed. Localized pitting, and intergranular and exfoliation corrosion occurred during the outdoor exposure of aluminum alloy specimens in a marine atmosphere. The degree of severity of atmospheric corrosion increased with increasing duration of exposure. The effects of Fe-rich constituent particles (Al₂₃CuFe₄) and grain boundary precipitates (MgZn₂) on the marine atmospheric corrosion behavior were discussed. In addition, when the exposure time was increased from 0 days to 15 days, the average fatigue life of aluminum alloy specimens decreased dramatically from about 125.16 × 10⁴ cycles to 16.58 × 10⁴ cycles. As the exposure time was further increased to 180 days, the average fatigue life slowly decreased to about 6.21 × 10⁴ cycles. The fatigue fracture characteristics and the effect mechanism of marine atmospheric pre-corrosion on the fatigue life of 7075-T73 aluminum alloy were also analyzed.

The dynamic recrystallization (DRX) behavior of Ti-45Al-8.5Nb-0.2W-0.2B-0.3Y (at %) alloy has been investigated through hot compression tests. The tests were executed at a temperature range of 1000–1200 °C and a strain rate range of 0.001–1 s⁻¹ under a true strain of 0.9. It was found that the α₂ phase which is produced during heat treatment is reduced during hot compression due to thermo-mechanical coupling. The value of the activation energy is 506.38 KJ/mol. With the increase in deformation temperature and the decrease in strain rate, DRX is more likely to occur, as a result of sufficient time and energy for the DRX process. Furthermore, the volume fraction of high angle grain boundaries increases to 89.01% at a temperature of 1200 °C and the strain rate of 0.001 s⁻¹, meaning completely dynamic recrystallization. In addition, DRX is related to the formation of twin boundaries. The volume fraction of twin boundaries rises to 16.93% at the same condition of completely dynamic recrystallization.

Using additive friction stir deposition (AFSD), the poor weldability of 1045 steel can be solved, facilitating the efficient and high-performance additive manufacturing of its components. This study selected spherical 1045 steel powder and investigated key factors influencing mechanical properties, including deposition temperature, tool rotational rate, and axial force. The results showed that dynamic recrystallization (DRX) occurred in AFSD 1045 steel, which produced randomly oriented fine equiaxed grains with a size range of 1–3 µm and was sensitive to changes in tool rotational rate and axial force. The AFSD 1045 steel, with a maximum surface hardness of 477.2 HV, ultimate tensile strength of 1061.9–1172.3 MPa, and elongation of 8.6–19.0%, has superior overall mechanical properties compared with other forming processes. Moreover, by analyzing tensile fracture morphology, geometrically necessary dislocation (GND) density, and coincidence site lattice (CSL) boundary distribution characteristics, the strengthening mechanism in AFSD 1045 steel was discussed. The research findings serve as a reference for optimizing the AFSD process for 1045 steel and supply a new alternative for joining and manufacturing this material.