Anisotropy of Microstructure and Tensile Properties of Additive Manufactured ZTC4 Alloy

ZTC4 alloy prepared by electron beam melting was hot isostatically pressed, the macro-and microstructure were characterized by stereo microscopy and optical microscopy, the tensile properties were tested and the fracture profiles were characterized using scanning electron microscopy. The results show that: The vertical deposition samples exhibit coarsen epitaxial columnar grains and the parallel samples show equiaxed grains, and microstructure are basket-weave α+β phase. The vertical deposition samples exhibit very high ultimate tensile strength and yield strength but poor ductility with elongation and shrinkage, and show generally more planar and faceted fracture morphology. The anisotropy in tensile properties is mainly due to the difference in the orientation of the columnar grains with respect to the tensile test direction, and the characteristics of the minor fracture plane are mainly related to the α colonies.

Morfologi Dan Sifat Optik Lapisan Tipis Opal yang Dideposisi Menggunakan Metode Modified Vertical Deposition

Telah dilakukan pembuatan lapisan tipis opal dengan menggunakan metode modified vertical deposition. Pada penelitian ini dilakukan analisis pengaruh kecepatan penarikan substrat dari suspensi koloid polysterene terhadap sifat optik dan homogenitas ketebalan lapisan tipis opal. Pembuatan sampel dilakukan dengan kecepatan penarikan 1 mm/jam, 5 mm/jam, 10 mm/jam dan 12 mm/jam. Sampel dikarakterisasi menggunakan mikroskop optik, spektrofotometer UV-Vis dan SEM (Scanning Electron Microscopy). Mikroskop Optik menunjukkan ketebalan lapisan opal yang tidak homogen. Karakterisasi UV-Vis menunjukkan adanya puncak absorbansi pada lapisan opal pada kecepatan 1 mm/jam sedangkan SEM menunjukkan adanya lapisan opal yang multilayer (berlapis banyak) pada kecepatan penarikan 1 mm/jam. Kata kunci: Lapisan tipis opal, Mikroskop Optik, SEM, UV-Vis, variasi kecepatan.

A study of methods to prevent piping and erosion in buffer materials intended for a vertical deposition hole at the Horonobe Underground Research Laboratory

Piping and erosion phenomena are serious problems affecting the integrity of buffer materials, which are an element of engineered barrier systems in the geological disposal of high-level radioactive waste. In this study, the outflow behaviour and the condition of buffer materials are investigated using a test pit drilled into host rock at the Horonobe Underground Research Laboratory to consider countermeasures to contain the outflow of the buffer material. The results are as follows: (1) Piping and erosion phenomena occur irrespective of the injection flow rate. However, when the rate is small, the buffer material is considered to be self-repairing and the outflow of the buffer material can be suppressed. (2) When the injection water contains large amounts of electrolytes, the surface of the buffer material peels off and precipitates, probably decreasing the waterproof performance. (3) Bentonite pellets are likely to be an effective countermeasure against piping and erosion.

Microstructure and enhanced photoluminescence of ZnO/V2O5 composite

Submicron zinc oxide (ZnO) spheres prepared by a two-stage hydrothermal method were assembled into a layer on a substrate by vertical deposition. Vanadium pentoxide (V2O5) was deposited onto the top of ZnO spheres by magnetron sputtering followed by annealing in oxygen atmosphere at 500[Formula: see text]C for an hour. The microstructures and optical properties of the prepared samples were investigated. The photoluminescence (PL) results indicate that the intensity of PL in the annealed ZnO/V2O5 composite microstructures is dramatically improved compared to the constituent V2O5 and ZnO spheres. The intensity enhancement of light emission from the ZnO/V2O5 composite may be attributed to the special microstructure of ZnO particles and the coupling effect between ZnO and V2O5. This transition oxide composite may possibly be developed into a new type of high-efficiency light emitting material.