Evolution of zinc morphology during continuous electrodeposition

The morphology evolution of zinc continuous electrodeposits with nano-sized crystals on the ferrite substrate has been studied by in-situ scanning tunnel spectroscopy (STM). It is found that the morphology of zinc electrodeposits varies from initial granules with a size of about 30nm to layered platelets with increasing deposition time. Meanwhile, the crystal structure of the zinc electrodeposits is identified to be hexagonal η-phase by X-ray diffraction. The orientation relationship between zinc crystals and the substrate surface can be interpreted in terms of the misfit and the atomic correspondence of the interphase boundary between the η-phase deposits and α-Fe substrate.     

Application of soft reduction technique to continuous-casting billets

Soft reduction technique can decrease the presence of central porosity and centerline segregation, and thus to enhance the internal quality effectively. In order to produce high quality billets, Xinxing Ductile Cast Pipe Group Co. Ltd. of China has installed a set of soft reduction apparatus on No. 1 caster and has achieved a great success. The principle, operating conditions and controlling factors, and the specification of soft reduction for solidifying billets are introduced. In order to make the effectiveness of soft reduction clear, metallurgical evaluation is made. The results indicate that soft reduction can increase equiaxial zone by 3%.     

Dynamic recrystallization of electroformed copper liners of shaped charges in high-strain-rate plastic deformation

The microstructures in the electroformed copper liners of shaped charges after high-strain-rate plastic deformation were investigated by transmission electron microscopy (TEM). Meanwhile, the orientation distribution of the grains in the recovered slug was examined by the electron backscattering Kikuchi pattern (EBSP) technique. EBSP analysis illustrated that unlike the as-formed electroformed copper linersof shaped charges the grain orientations in the recovered slug are distributed along randomly all the directions after undergoing heavily strain deformation at high-strain rate. Optical microscopy shows a typical recrystallization structure, and TEM examination reveals dislocation cells existed in the thin foil specimen. These results indicate that dynamic recovery and recrystallization occur during this plastic deformation process, and the associated deformation temperature is considered to be higher than 0.6 times the melting point of copper.     

厚度变化对中厚环形板非线性振动的影响

对变厚度中厚环板的非线性振动问题进行了讨论,采用半解析法及罚函数法,得到了在不同边界条件下,厚度变化对非线性振动基频的影响曲线图及最佳的厚度分布图．     

Evolution of microstructure and electromagnetic interference shielding performance during the ZrC precursor thermal decomposition process

A polymer-derived ZrC ceramic with excellent electromagnetic interference(EMI) shielding performance was developed to meet ultra-high temperature requirements. The thermal decomposition process of ZrC organic precursor was studied to reveal the evolution of phase composition, microstructure, and EMI shielding performance. Furthermore, the carbothermal reduction reaction occurred at 1300°C, and the transition from ZrO2 to ZrC was completed at 1700°C. With the increase in the annealing temperature...     

Review of the fabrication and application of porous materials from silicon-rich industrial solid waste

Porous materials have promise as sound insulation, heat barrier, vibration attenuation, and catalysts. Most industrial solid wastes, such as tailings, coal gangue, and fly ash are rich in silicon. Additionally, a high silicon content waste is a potential raw material for the syn- thesis of silicon-based, multi-porous materials such as zeolites, mesoporous silica, glass-ceramics, and geopolymer foams. Representative sil- icon-rich industrial solid wastes (SRISWs) are the focus of this mini review of the processing and application of porous silicon materials with respect to the physical and chemical properties of the SRISW. The transformation methods of preparing porous materials from SRISWs are summarized, and their research status in micro-, meso-, and macro-scale porous materials are described. Possible problems in the application of SRISWs and in the preparation of functional porous materials are analyzed, and their development prospects are discussed. This review should provide a typical reference for the recycling and use of industrial solid wastes to develop sustainable “green materials.”     

Chemical vapor deposition growth behavior of graphene

The optimized growth parameters of graphene with different morphologies,such as dendrites,rectangle,and hexagon,have been obtained by low-pressure chemical vapor deposition on polycrystalline copper substrates.The evolution of fractal graphene,which grew on the polycrystalline copper substrate,has also been observed.When the equilibrium growth state of graphene is disrupted,its intrinsic hexagonal symmetry structure will change into a non-hexagonal symmetry structure.Then,we present a systematic and comprehensive study of the evolution of graphene with different morphologies grown on solid copper as a function of the volume ratio of methane to hydrogen in a controllable manner.Moreover,the phenomena of stitching snow-like graphene together and stacking graphene with different angles was also observed.