Marine noise pollution generated by propellers is of wide concern. Traditional propeller materials (nickel–aluminum bronze (NAB) alloys) can no longer meet the requirements for reducing shaft vibration. However, the Mn–Cu alloy developed to solve the problem of propeller vibration is affected by seawater corrosion, which greatly limits the application of the alloy in the field of marine materials. In this study, the M2052–NAB gradient alloy was developed for the first time using LENS technology to improve the corrosion resistance while retaining the damping properties of the M2052 alloy. We hope this alloy can provide a material research basis for the development of low-noise propellers. This study shows that, after solution-aging of M2052 alloy as the matrix, the martensitic transformation temperature increased to approach the antiferromagnetic transformation temperature, which promoted twinning and martensitic transformation. The aging process also eliminated dendrite segregation, promoted the equiaxed γ-MnCu phase, and increased the crystal size to reduce the number of dislocations, resulting in obvious modulus softening of the alloy. NAB after deposition had higher hardness and good corrosion resistance than the as-cast alloy, which offers good corrosion protection for the M2052 alloy. This research provides new material options for the field of shipbuilding.

This work studies the static mechanical properties of grid stiffened polymer composites. This developed composite is expected to have an ultra-higher mechanical performance than traditional composite structures. Static mechanical measurements show that the combination of gridding reinforcement and epoxy polymer (Diglycidyl 4,5-epoxy cyclohexane-1,2-dicarboxylate) helps the advanced composite to possess extremely high mechanical properties, such as resistive properties in axial pressure (more than 160% improvement) and external pressure (more than 102% improvement) for comparison. Subsequently, the effects of wetting angle of reinforcement, quantity of gridding reinforcement, and type of grid on the mechanical properties of the advanced polymer composites have been studied and analyzed. Finally, the finite element model (FEM) method is employed to substantiate these experimental results. The FEM simulation results are in such great agreement with the experimental results that the standard deviations between them are strictly limited to 15%. Furthermore, it demonstrates that the FEM technology is an effective approach for predicting and optimizing structure design, as well as the mechanical behaviors.

Here, we report a skeletal nickel catalyst prepared by cumulative processing. The Ni, Al, and CoCrMo multi-component alloys were printed by a dual-powder laser-engineered net-shaping system, and alloy samples with different components were obtained through high-throughput design. After leaching in 5 mol/L NaOH at 40 °C for 2 h, the specific surface area of the catalyst increased with increasing Al content. Increasing the leaching temperature and prolonging the leaching time also effectively increased the specific surface area of the catalyst. After leaching at 80 °C for 12 h, the specific surface area was 42.36 m²/g. After cleaning and hydrogen-reduction treatment at 400 °C, the catalyst showed high catalytic activity. The highest conversion rate of CO reached 89.56%, and the selectivity of CH₄ remained above 98% for a long time.