Phase composition and concentration of yttriumin films during the deposition of aluminumand aluminum alloys from the gas phase

The work is devoted to the study of the stabilizing effect of yttrium additions during the deposition of thin aluminum films, which are used for the manufacture of elements of micro- and nanoelectronic devices. The surfaces of Al films doped with aluminum oxide were investigated using a scanning electron microscope before and after annealing for 300420 s at a temperature of 500 C. It is shown that fine alumina particles are uniformly distributed on the surface of the films during thermal evaporation of a wire made of an Al Al2O3 alloy. By the method of quantitative metallography, the content of the AlxOy phase in the Al films was determined: when spraying wire from the Al Al2O3 alloy, its content was 1012% of the mass fraction; when spraying wire made of Al Al2O3 alloy and Al wire in a ratio of 50:50 1% mass fraction.

Experimental Study of the Behavior of Phase Change Materials during Interrupted Phase Change Processes

This research article explores the behavior of a phase change material (PCM) when it undergoes interrupted melting and freezing, through experimental investigations using a heat flow meter apparatus. A fatty acid-based organic PCM, encapsulated within polyethylene and thin aluminum foil layers, was experimentally tested in this study. Experiments were designed to represent multiple interrupted phase change scenarios that could occur within PCMs applied in buildings. The experimental results were analyzed and compared with previously reported assumptions in numerical models dealing with PCM hysteresis and interrupted phase change processes. These comparisons indicated that the assumptions used in the different numerical models considered can capture the interrupted phase change phenomena with varying degrees of accuracy. The findings also highlighted the need for additional experimental research on different phase change processes that can occur in building applications of PCMs.

Casting of Wire Using a Twin Wheel Caster

A twin-wheel caster for casting thin aluminum alloy wire was designed, assembled, and tested. Molten metal was ejected from the nozzle (cross-sectional area: 4 mm2) of a crucible into a triangular groove that was machined on the outer surface of the lower wheel. The metal was solidified by the upper and lower wheels. Wire made of Al-1.2%Fe or 6061 aluminum alloy, whose cross-sectional area was smaller than 20 mm2, could be cast at a speed of 6 or 7 m/min. The upper and lower wheels were made of copper to increase the cooling rate. The diameter of the upper and lower wheels was 200 and 600 mm, respectively. The thickness of the wheels was 10 mm.

Localized overheating on aluminum metafilms mediated by surface plasmons

We studied the increase in temperature of systems formed by thin aluminum films deposited on texturized substrates which we denominated aluminum metafilms. By varying the geometric parameters of the metafilms, surface plasmons in the wavelength range of ~420-770 nm were excited. Temperature measurements as a function of the intensity of incident radiation in the interval from 0-to 4X10^18 (photons/s cm^2) using wavelengths of 445, 532 and 650 nm, showed temperature increases up to ~200 K, these attributed to metafilm morphology and hot electrons result of the non-radiative decay of the surface plasmons. Also increases up to 2.3X10^(-4) Ohm cm in electrical resistivity were recorded when the metafilms were radiated for times of ~1 s; when the exposure times were greater than ~4 s, irreversibly changes in the morphology of the samples were observed.

Casting of Thin Aluminum Alloy Rod Using Twin Wheel Caster Equipped with Rotating Side Dam Plates

A thin aluminum rod (width: 5 mm) was cast using a twin-wheel caster equipped with rotating side-dam plates. The upper and lower casting wheels were made of copper. The width of the flat upper and lower casting wheels was 5 mm. The rotating side-dam plate was made of mild steel. Paper 0.5 mm thick was pasted onto the plate. Boron nitride was sprayed onto the paper as an insulator and lubricant. A 6061 aluminum alloy thin rod could be cast continuously at casting speeds of 4 and 5 m/min. Molten metal was poured onto the lower wheel from a launder and conveyed into a square gap made by the lower wheel, upper wheel, and side-dam plates. The cross section of the cast rod was rectangular. The cross-sectional area of the rectangular rod was 12 to 15 mm2.

X-ray Radiography Inspection of Pores of Thin Aluminum Foam during Press Forming Immediately after Foaming

Forming aluminum foam to the desired shape while retaining its pore structures is essential for manufacturing aluminum foam products. Recently, a press forming process for aluminum foam that is performed after precursor foaming but before solidification has been proposed. In this study, to track individual pores throughout press forming immediately after foaming, X-ray radiography inspection was applied. A thin precursor was used, and foaming was constrained to the X-ray transmission direction. It was shown that, although some pores coalesced with other pores, the pores did not collapse during press forming. In addition, the porosity of aluminum foam evaluated from X-ray transmission images was constant during press forming. Some pores retained their shape during press forming but their position was changed by the material flow generated by press forming. These results show that by press forming before the solidification of aluminum foam, aluminum foam can be shaped without the collapse of pores.