Evaluation of EN AW-5083 aluminum alloy homogeneity using statistical analysis of mechanical properties

In the frame of this investigation, the homogeneity of six (6) ingots of aluminum alloy EN AW-5083 cast by semi-continuous vertical Direct Chill casting (DC) Process was investigated correlating mechanical properties in as-cast and homogenized condition. The investigation followed the static design of the Latin square. Determination of the ultimate tensile strength and elongation across the cross-sectioned sliced at the ingots’ fronts and rears in as-cast state revealed differences per cross section of each particular slice. Comparison of obtained differences enabled evaluation of mechanical properties homogeneity of the ingots as a whole. The influence and significance of homogenization was also quantified correlating the mechanical properties results for as-cast and homogenized state at the front and rear position in ingot. The results were processed using the StatSoft® STATISTICA 13.2 software package using charge, slice height and slice width as sources of variability. Comparison of obtained statistical results for both states respectively in respect to the sampling position enabled estimation of homogenization process influence on mechanical properties

State of the direct reduction and reduction smelting processes

For quite a long time efforts have been made to develop processes for producing iron i.e. steel without employing conventional procedures - from ore, coke, blast furnace, iron, electric arc furnace, converter to steel. The insufficient availability and the high price of the coking coals have forced many countries to research and adopt the non-coke-consuming reduction and metal manufacturing processes (non-coke metallurgy, direct reduction, direct processes). This paper represents a survey of the most relevant processes from this domain by the end of 2000, which display a constant increase in the modern process metallurgy

PIT NUCLEATION ON AS-CAST ALUMINIUIM ALLOY AW-5083 IN 0.01M NaCl

Abstract The use of aluminium alloys in a wide range of technical applications is related mostly to the two fact

Pit nucleation on as-cast aluminiuim alloy AW-5083 in 0.01M NaCl

The use of aluminium alloys in a wide range of technical applications is related mostly to the two facts: they facilitate weight saving of final products (if compared to the steel) and they are prone to spontaneous passivity due to the coherent surface oxide layer which impedes further reaction of aluminium with the environment. Among the commercial Al alloys, EN AW-5083 alloy is a representative non-heat treatable Al-Mg based alloy which possesses many interesting characteristics as a structural material, such as low price, moderately high strength, high formability in conjunction with superplasticity and good corrosion resistance in marine atmospheres. Aiming to enhance the knowledge of possible interactions of studied alloy EN AW-5083 in as-cast condition with chloride media, electrochemical measurements were used to follow the pitting behaviour in 0.01 M NaCl. The results of tests have shown that susceptibility of alloy to pitting corrosion is strongly influenced by the microstructural constituents of the alloy in as-cast condition

An intermetallic bonding between an aluminum piston alloy and ring carrier

ABSTRACT: This paper presents the results of investigating the formation of intermetallic bond between aring carrier and aluminum piston alloy. The ring carrier is made of austenitic cast iron (Ni-Resist) in order toincrease the wear resistance of the first ring groove and applied in highly loaded diesel engines. Metallographicexamination of the quality of alfin bond was done. A metallographic investigation using an optical microscopein combination with the SEM/EDS analysis of the quality of the intermetallic bonding layer was done. The testresults show that can be made successfully as well as the formation of metal connection (alfin bond) between thering carrier and aluminum piston alloy. (PDF) The intermetallic bonding between a ring carrier and aluminum piston alloy. Available from: https://www.researchgate.net/publication/283876254_The_intermetallic_bonding_between_a_ring_carrier_and_aluminum_piston_alloy [accessed Sep 15 2023]

The effect of different extractants on lead desorption from a natural mineral

Natural minerals, such as quartz, clinoptilolite and calcite, are useful as sorbents for various applications, but their content of heavy metals ions is the most problematic obstacle to their application. Before their (re)use, the minerals must be purified. In this work, the subject was desorption of lead from a natural multi-component mineral sample consisting of a mixture of silicates (mainly quartz and clinoptilolite) and calcite formations. Besides deionized water, different extraction solutions were tested: NaCl, KCl, CaCl2, MgCl2, HCl, HNO3, EDTA, EDTA/HCl, EDTA/NaOAc-HOAc, HOAc, NaOAc and NaOAc-HOAc. Several parameters were varied in order to obtain the optimal conditions for the desorption process: the concentration of the extraction solution, the ratio of the mass of the sample and volume of the extractant, and the pH value of the suspension. The best purification effect in one desorption cycle was obtained when 0.1 M EDTA, at a pH value of 3.5 (0.2 M EDTA was mixed with 0.01 M acetic buffer, at pH value 3.0, in ratio 1:1) was applied. Sequential extraction (5 consecutive iterations) was performed to provide a more efficient purification process. The lead content (58.20 mg/kg) was decreased by: 20% (using HOAc), 21% (using EDTA) and by more than 50% (using EDTA/NaOAc-HOAc). The pH value and conductivity were measured at all critical points to clarify the mechanism of the desorption process. The formation of Pb-EDTA complex is the result of two parallel phenomena, complexing and ion-exchange. An enhanced adsorption capacity and an improved microelement profile for the purified samples were also attained. The mineralogical and radiochemical performances of the sample were determined by the X-ray diffraction and gamma spectrometry techniques. Microelement analyses of the native and purified samples were performed by inductively coupled plasma optical emission spectroscopy (ICP-OES)

Effects of dispersion and particle-matrix interactions on mechanical and thermal properties of hnt/epoxy nanocomposite materials

Halloysite nanotubes (HNTs), naturally occurring as aluminosilicate nanoclay mineral, have recently emerged as a possible nanomaterial for countless applications due to their specific chemical structure, tubular shape, high aspect ratio, biocompatibility and low toxicity. In this study, HNTs were incorporated into the epoxy resin matrix to improve its mechanical properties and thermal stability. However, heterogeneous size, surface charge and surface hydrogen bond formation, result in aggregation of HNTs in epoxies to a certain extent. Three specific techniques were used to integrate HNTs into neat epoxy resin (NE). The structure and morphology of the embedded nanotubes were confirmed by Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Tensile testing was carried out and the fractured surface of the tested specimen was analysed using scanning electron microscopy (SEM). The thermal stability of the prepared nanocomposite materials was investigated by thermogravimetric (TG) and derivative thermogravimetry (DTG) studies. The obtained results indicated that improved properties of HNTs/epoxy nanocomposite materials were related to the unique properties of well-dispersed HNTs, agglomerate scale, and reduced void presence, and could be controlled by the manufacturing processes