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Go to Editorial ManagerNanoparticles show mechanical, electrical, chemical and optical properties that are different and superior to bulk materials. In the present work, α-Alumina nanoparticles were synthesized using the nonorganic Sol-Gel method under controlled conditions. Because of the low cost of its raw materials, low manufacturing temperature and the high purity of the product, Sol-Gel method is the best in the manufacture of nanostructures like metal oxide nanoparticles. The precursor of the Sol-Gel process was aluminum nitrate with ethanol. The prepared nanopowder was evaluated by X-ray diffraction (XRD), scanning electron microscope (SEM), electron dispersive spectroscope (EDS) and Malvern Zetasize analyzer.
This paper aims to investigate the effect of Ag nanoparticles addition in different percentages (0.12 wt. %, 0.15 wt. %, 0.25 wt. %, 0.35 wt. %) on the microstructure properties of Cu-21%Zn-6%Al shape memory alloy. Optical and SEM were carried out to studied such effects. Two heat treatments were carried out at (825 ℃ and 850 ℃) for 10 min and quenched in ice water. It was observed that both of heat treatment lead to formation M18R martensite with V-shape and needle like, but raising the temperature of heat treatment from 825 ℃ to 850 ℃ lead to a decrease formation α phase, which leads to improving the shape memory properties. Refinement of the grain size resulted as Ag nanoparticles addition increased from 0 to 0.25 wt. %, the grain size decreases from 1551 μm to 212 μm with reduction of 86.32 wt. % at 0.25 wt. % Ag. The microstructure observation indicated that the Ag nanoparticles addition leads to creating a multi-variant oriented martensite microstructure after quenching process in ice water.
Retained Austenite (RA) has great deal with the me- chanical properties of high strength low alloy steel. Therefore, in this paper, Retained Austenite volume fractions have been evaluated in AISI4340 alloy steel using two well-known meth- ods, X-Ray diffraction (XRD) and magnetic measurement methods. The specimens were heat treated using different heat- ing temperature and different cooling rate (different quenching media). A comparison between the results of two methods proved that there results were approximately Identical .The results show that Retained Austenite formation increase as heating (Austenizing ) temperature increase for the same quenching media ,as well as ,it increases by increasing cooling rate . The maximum amount of Retained Austenite found as (27.2 Wt %) which recognized when the specimens heated up to 1000˚C then quenched in Water while the minimum amount of Retained Austenite found as ( 7.06 wt%) when the specimens heated up to ( 800 ˚C) then quenched in Sand. Hardness tests using Vickers and Rockwell methods were used and the results show that hardness values decreased with increasing heating temperatures and the maximum Vickers micro-hardness and Rockwell hardness numbers were equal to (121.8HRB) and ( 516.35 HV) which were detected when heating up of the speci- mens were up to 800 ˚C then quenched in water. Tensile tests show that increasing cooling rate lead to increasing in Strength due to increasing of hardness which in turn, leads to increase in yielding points and ultimate strengths. Retained austenite effects on microstructure were investigated using scanning electron microscopy (SEM) and optical microscopy and the results show that at low cooling rate the microstructure consist of bainite and/or martensite phase with small amount of re- tained austenite, while, increasing heating temperature and cooling rate results in microstructure consist of martensite and retained austenite phases.
The enormous volume of crude oil that needs to be transported results from the growing demand for petroleum. One of the most practical ways to move crude oil is via pipelines. This paper's primary objective is to examine the effects of sulphur, one of the components of crude oil, on welded pipes (API 5L X60, X46, and X42 pipes as well as ASTM A106 pipes). It also aims to show how sulphur content influences different kinds of pipes separately from the other important components of crude oil. The sulphur content of crude oil is determined using the TR-TCXRF equipment. The corrosion rates of welded pipes in four immersion solutions (Different percentages of sulphur content) were computed using weight loss. The samples' corrosion characteristics were assessed morphologically using an optical microscope (OM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Petroleum welded pipelines' mechanical qualities and resistance to corrosion are significantly impacted by sulphur; an increase in sulphur concentration resulted in a higher rate of corrosion and a decrease in mechanical properties. Among all the welded pipes utilized in the paper, the API 5L X60 welded pipe had the highest corrosion rate, whereas X46 welded pipe was more corrosion-resistant than X46 and X42 in API 5L-type pipes and ASTM A106 pipe.