In this paper, a laser-based directed energy deposition (DED) technique is used to fabricate FeCoNiCr and CrMnFeCoNi multi-principal-element alloys (MPEAs). Comparing the above samples, the FeCoNiCr samples with coarse columnar grains cracked, while the CrMnFeCoNi samples with equiaxed grain were crack-free. The strategy that removes cracks is to induce a columnar-grain-to-equiaxed-grain transition (CET) with Mn addition to offer more grain boundaries to withstand residual stress in the process of DED-fabricated FeCoNiCr and to help minimize hot cracking. Furthermore, the yield strength, tensile strength, and tensile ductility of the DED-fabricated CrMnFeCoNi obviously improved compared with the DED-fabricated CoCrFeNi and exhibited better isotropic mechanical properties. The present work provides a novel strategy to utilize CET for resisting crack propagation in the process DED-fabricated MPEAs and improvement in mechanical properties of MPEAs.

Herein, the Nd–Ce–Fe–B film was used as a model system to evaluate the full potential of Ce magnets with high Ce concentration and characterize the high-coercivity mechanism of magnets. A significant coercivity enhancement and the high-coercivity of 24.8 kOe (much higher than previously reported values) were achieved in very high Ce-substituted (67.3 at%) film magnets by the design of Ce/Cu diffusion layers via a new multifaceted approach. The mechanism of enhanced coercivity was comprehensively analyzed based on the microstructure and domain-structure observations as well as micro-magnetic theory. The magnetically well-separated grains with fine size and unexpected superior microstructure are responsible for the extremely high coercivity in these high Ce-containing film magnets. The microstructure parameters α and N_eff in the present high-coercivity Ce film magnet are superior than those in the Nd–Fe–B magnets due to the specific character of Ce-metal boundary phases. Our study indicates that although the intrinsic anisotropy H_A decreases distinctly in high Ce-substituted magnets, a high coercivity can still be obtained due to the accessible superior microstructure as compared to the case of the Nd–Fe–B magnets. Our study opens up the door for more effective utilization of highly abundant and cheap Ce resource. It is also significant for diffusion layer designs in high-performance diffusion-processed magnets.

Flaky Ni/Ni-Cu-coated glass fiber/epoxy resin composite coatings were prepared using the glass fibers and flaky nickel powders as fillers and epoxy resin as binder. The conductivity and...

A proper understanding of hydrogen–trap interactions in materials is of considerable significance, as it holds the potential to provide promising solutions to the long-standing issue of hydrogen embrittlement. In the present study, we employed a novel integrated approach combining electro-oxidation (EO) technique and thermal desorption spectroscopy (TDS) to characterize both reversible and irreversible deuterium in Fe samples. The samples were deuterium-charged at 500 kPa and temperatures ranged from 25 °C to 500 °C. Deuterium retention was measured by TDS for samples with and without EO treatment. Experimental findings demonstrate that the EO technique not only accelerates the expulsion of spontaneously releasable deuterium but also efficiently removes the majority of non-spontaneously releasable deuterium. It is evidenced that the proportion of reversible deuterium in the non-spontaneously releasable deuterium fraction reaches as high as 70%. Furthermore, an illustrative energy level diagram concerning the different barriers depending on the trap sites was devised to elucidate the trapping and diffusion behaviors of deuterium. Correspondingly, the microstructural trap sites associated with reversible or irreversible states were discussed in detail. This work enhances our understanding of hydrogen-Fe material interactions, thereby strengthening the fundamental theories underlying hydrogen embrittlement.

Graphene oxide (GO) membranes show good separation performance in membrane distillation processes, which require at least single-sided hydrophobic surface to resist liquid penetration, but such hydrophobic GO membrane cannot be facilely prepared by conventional wet chemical processes. Here, a pulsed plasma hexamethyldisiloxane (HMDSO) process was investigated, with the highest surface contact angle of 124^o obtained. The results demonstrate that plasma deposition process can provide a proper route to prepare selectively hydrophobic GO films, which facilitates their applications for membrane distillation processes and related fields.