The interfacial microstructures of borides in Fe–Cr–B cast steels with different Cr contents after hot dipping in Al–Zn alloys were investigated. The results showed: the Cr contained in Fe–Cr–B cast steel had a key influence on the formation of periodic layered structures (PLSs) between Cr-rich borides, which were (Cr,Fe)₂B, and Al–Zn melt. The contents of Zn in the Al–Zn melts also significantly influenced the formation of periodic layered structures, which depended on the complex relationship between the content of Cr contained in Fe–Cr–B cast steel and that of Zn in Al–Zn melt. Within a certain range, the higher the content of Cr is, the larger the maximum value of Zn in Al–Zn melt that could form PLS at the (Cr,Fe)₂B/Al–Zn interface could be.

In this paper, the composition of binary nonazeotropic working fluids is explored from the perspective of improving OTEC-ORC efficiency, and the turbine is designed to accommodate with the working fluid. It is found that the OTEC-ORC using a R152a/R32 mixture as the working fluid is significantly higher than the OTEC-ORC thermal efficiency and system efficiency of the pure NH3, and the optimal composition of the mixed working fluid R152a/R32 is determined to be 85:15 with the thermal efficiency and the system efficiency of 2.8 and 1.7, respectively, improving by 35.7 and 151.2 compared to the NH₃ ORC. According to the determined working fluid, a one-dimensional (1-D) design and CFD simulation analysis simulation are carried out on the turbine. The 1-D calculation results are in good agreement with the three-dimensional (3-D) results. At the design point, the turbine output is 83.84kW, and the isentropic efficiency is 87.53. At the off-design point, turbines have better off-design performance, indicating that the designed turbine also has good adaptability.

To address surface defects and enhance the wear resistance of 316L stainless steel parts fabricated by Selective Laser Melting (SLM), this study applied shot peening (SP) surface treatment to the SLM-processed samples. Ball-on-disk tribological tests were systematically conducted under water-lubricated conditions to investigate the evolution of surface morphology, microstructure, microhardness, and tribological performance before and after SP. The results indicate that SP induced severe plastic deformation in the surface layer, effectively refining the coarse columnar crystals and melt pool structures characteristic of SLM, and forming a crystalline hardened layer with a depth of 70–80 μm. Consequently, the surface microhardness increased by 21.97% compared to the un-peened samples. Under loads of 20 N and 30 N, the coefficient of friction (COF) of the SP-treated samples decreased by 16.36% and 12.4%, while the wear rate was reduced by 17.09% and 14.9%, respectively. In this load range, the samples primarily exhibited uniform plowing and localized adhesive wear, demonstrating significantly improved resistance to plastic deformation and crack initiation. However, when the load increased to 40 N, intense stress and thermal effects diminished the strengthening benefits of SP, resulting in no significant difference in tribological performance between the SP-treated and untreated samples. At this stage, the dominant wear mechanism transitioned to severe plastic deformation, extensive delamination, and thermally induced adhesion.