摘要：How to increase strength without sacrificing ductility has been developed as a key goal in the manufacture of high-performance metals or alloys. Herein, the double-nanophase intragranular yttrium oxide dispersion strengthened iron alloy with high strength and appreciable ductility was fabricated by solution combustion route and subsequent spark plasma sintering, and the influences of yttrium oxide content and sintering temperature on microstructures and mechanical properties were investigated. The results show at the same sintering temperature,with the increase of yttrium oxide content, the relative density of the sintered alloy decreases and the strength increases. For Fe–2wt%Y_(2)O_(3)alloy, as the sintering temperature increases gradually, the compressive strength decreases, while the strain-to-failure increases. The Fe–2wt%Y_(2)O_(3)alloy with 15.5 nm Y_(2)O_(3)particles uniformly distributed into the 147.5 nm iron grain interior sintered at 650℃ presents a high ultimate compressive strength of 1.86 GPa and large strain-to-failure of 29%. The grain boundary strengthening and intragranular second-phase particle dispersion strengthening are the main dominant mechanisms to enhance the mechanical properties of the alloy.

摘要：Traditional 3Ni weathering steel cannot completely meet the requirements for offshore engineering development,resulting in the design of novel 3Ni steel with the addition of microalloy elements such as Mn or Nb for strength enhancement becoming a *** stress-assisted corrosion behavior of a novel designed high-strength 3Ni steel was investigated in the current study using the corrosion big data *** information on the corrosion process was recorded using the galvanic corrosion current monitoring *** gradi-ent boosting decision tree(GBDT)machine learning method was used to mine the corrosion mechanism,and the importance of the struc-ture factor was *** exposure tests were conducted to verify the calculated results using the GBDT *** indic-ated that the GBDT method can be effectively used to study the influence of structural factors on the corrosion process of 3Ni ***-ferent mechanisms for the addition of Mn and Cu to the stress-assisted corrosion of 3Ni steel suggested that Mn and Cu have no obvious effect on the corrosion rate of non-stressed 3Ni steel during the early stage of *** the corrosion reached a stable state,the in-crease in Mn element content increased the corrosion rate of 3Ni steel,while Cu reduced this *** the presence of stress,the increase in Mn element content and Cu addition can inhibit the corrosion *** corrosion law of outdoor-exposed 3Ni steel is consistent with the law based on corrosion big data technology,verifying the reliability of the big data evaluation method and data prediction model selection.

摘要：Precise control of the local environment and electronic state of the guest is an important method of controlling catalytic activity and reaction *** this paper,guest Pd NPs were introduced into a series of host UiO-67 MOFs with different functional ligands and metal nodes,the microenvironment and local electronic structure of Pd is modulated by introducing bipyridine groups and changing metal nodes(Ce_(6)O_(6) or Zr_(6)O_(6)).The bipyridine groups not only promoted the dispersion Pd NPs,but also facilitated electron transfer between Pd and UiO-67 MOFs through the formation of Pd-N *** with Zr6 clusters,the tunability and orbital hybridisation of the 4f electronic structure in the Ce_(6) clusters modulate the electronic structure of Pd through the construction of the Ce-O-Pd *** optimal catalyst Pd/UiO-67(Ce)-bpy presented excellent low-temperature activity towards dicyclopentadiene hydrogenation with a conversion of>99% and a selectivity of>99%(50℃,10 bar).The results show that the synergy of Ce-O-Pd and Pd-N promotes the formation of active Pd^(δ+),which not only enhances the adsorption of H_(2) and electron-rich C=C bonds,but also contributes to the reduction of proton migration distance and improves proton utilization *** results provide valuable insights for investigating the regulatory role of the host MOFs,the nature of host-guest interactions,and their correlation with catalytic performance.

摘要：本文研究了一种新型低密度(~6.24 g cm^(-3))双相AlTiVCoNi高熵合金,其组织结构由有序L21高熵金属间化合物、无序体心立方结构和纳米L21相多层次结构构成.该合金在1200℃+24 h热处理下未发生相结构转变,在此条件下具有优异的高温相结构稳定性,其铸态和热处理态的压缩屈服强度相当,达到~1.6 GPa.另外,该合金在室温和600℃条件下表现出了优异的强塑性匹配和优异的比屈服强度,分别达到了约261和210 MPa g^(-1)cm^(3).该合金的超高强度主要源于有序L21相与体心立方相的半共格界面导致的一种强相结构稳定性和多层次结构的复合强化机制.该合金在800和1000℃压缩过程中出现了动态再结晶软化,使得其高温强度有所降低.这种“具有半共格界面L21+体心立方+纳米L21颗粒”的多层次结构设计为开发新型低密度耐高温高熵合金提供了一种新设计思路.