Showing papers in "Advances in Materials Sciences in 2016"

Temper Bead Welding of S420G2+M Steel in Water Environment

Abstract: The article presents the idea of the use of Temper Bead Welding (TBW) technique to improve the weldability of high strength steel at underwater wet welding conditions. Wet welding method with the use of covered electrodes is described. This work shows results of metallographic examinations and hardness measurements of samples of S420G2+M steel with weld beads performed under water. It has been shown that Temper Bead Welding technique may provide a way to reduce the hardness of the welds, thus is a useful method for improving weldability of high strength steel welded in underwater conditions. The optimum overlap of weld beads (pitch) was set of 55÷100%.

Concept of a Conducting Composite Material for Lightning Strike Protection

Abstract: Abstract The paper focuses on development of a multifunctional material which allows conducting of electrical current and simultaneously holds mechanical properties of a polymeric composite. Such material could be applied for exterior fuselage elements of an aircraft in order to minimize damage occurring during lightning strikes. The concept introduced in this paper is presented from the points of view of various scientific disciplines including materials science, chemistry, structural physics and mechanical engineering with a discussion on results achieved to-date and further plans of research.

Bacterial Nanocellulose as a Microbiological Derived Nanomaterial

Abstract: Bacterial nanocellulose (BNC) is a nanofibrilar polymer produced by strains such as Gluconacetobacter xylinus, one of the best bacterial species which given the highest efficiency in cellulose production. Bacterial cellulose is a biomaterial having unique properties such as: chemical purity, good mechanical strength, high flexibility, high absorbency, possibility of forming any shape and size and many others. Such a large number of advantages contributes to the widespread use of the BNC in food technology, paper, electronic industry, but also the architecture in use. However, the greatest hopes are using the BNC in medicine. This text contains information about bacterial nanocellulose, its specific mechanical and biological properties and current applications.

The Effect of Wet Underwater Welding on Cold Cracking Susceptibility of Duplex Stainless Steel

Abstract: Abstract The present work was conducted to assess the weldability of duplex stainless steel in underwater conditions. Metal manual arc welding (MMA) with the use of coated electrodes was used in the investigations. Tekken weldability tests were performed underwater at 0.5 m depth and in the air. Nondestructive tests, metallographic examinations of welds, ferrite content assessment in microstructure and hardness test were performed. The good weldability at underwater conditions of duplex stainless with the use of MMA method was confirmed, however difficulties in stable arc burning were revealed.

A study on the effect of different activating flux on A-TIG welding process of incoloy 800H

Abstract: Abstract This study investigates the effect of different activating flux such as V2O5, TiO2, MoO3, Cr2O3, and Al2O3 on A-TIG welding process of Incoloy 800H. The influence of the flux on the depth of penetration and on mechanical and metallurgical characteristics of the weld were studied and compared with autogeneous TIG welds which were welded with the same process parameters and conditions. The use of TiO2 flux gave full depth of penetration and the use of V2O5, Cr2O3 flux gave increased penetration as compared to autogeneous TIG welds while the use of Al2O3 and MoO3 led to the detoriation of the effect.

The Determinants of Morphology and Properties of the Nanohydroxyapatite Coating Deposited on the Ti13Zr13Nb Alloy by Electrophoretic Technique

Abstract: The titanium and its alloys belong at present to the most preferred and commonly applied biomaterials for load- bearing implants. The surfaces of biomaterials are subjected to modification, including the hydroxyapatite coatings deposited in order to ensure corrosion resistance and better joining between an implant and a bone through the possibility of ingrowth bone into the coating. In this paper, the morphology and properties of the nanohydroxyapatite coating deposited on the Ti13Zr13Nb flat surfaces using electrophoretic method are presented. Electrophoretic deposition at two different current values and two electrolytes (first – ethanol with nanoHAp, second – methanol with nanoHAp) was applied. The scanning electron microscopy examinations and wettability angle measurements showed an increase in the coating thickness, the surface coverage and decrease in biocompatibility with increasing voltage. The surface condition and biocompatibility of coatings were better when using methanol/nanoHAp solution as compared to the ethanol/nanoHAp one.

Kinetics of the Bainite Transformation in Austempered Ductile Iron ADI

Abstract: Abstract The aim of the present research is to check an analytical model of the kinetics of bainite transformation that will enable the producers of ADI to optimise the microstructure and mechanical properties and minimise the expensive and extensive experimental trials. A combination of thermodynamics and kinetic theory was used successfully to estimate the evolution of bainite as a function of temperature, time, chemical composition and austenite grain size and predict the processing window in austempered ductile iron using a bainite transformation model developed previously for high silicon steels. The results of the present research show that the bainitic model developed for high silicon steels is applicable for calculations of the processing window for ADI.

Experimental investigation of the three-point bending fatigue properties of carbon fiber composite laminates

Abstract: The three-point bending fatigue properties of carbon fiber epoxy matrix composite laminates were compared for fatigue loading stress levels of 75, 80 and 85%, and fatigue loading frequencies of 10, 15 and 20 Hz, respectively. The experimental results showed that the bending fatigue life of the composites obviously decreased with the increase of the fatigue loading stress level or the loading frequency. The fatigue damage accumulation process could be divided into three distinct stages according to the accumulation rate: fast, slow and then fast. When the loading stress level was increased from 75 to 85%, the duration of the third stage decreased from 40 to 10% of the overall fatigue life. When the loading frequency was increased from 10 to 20 Hz, the duration of the third stage increased from 20 to 40% of the overall fatigue life. Matrix cracking, fiber breaking, interface debonding and delamination were identified as the main three-point bending fatigue damage modes of the carbon fiber composite material, and the stress level and the loading frequency were found to significantly influence the fatigue failure properties of the composites.

Mechanical and Morphological Study of Arecanut Leaf Sheath (ALS), Coconut Leaf Sheath (CLS) and Coconut Stem Fiber (CSF)

Abstract: A quantitative as well as morphological analysis of three fibers (arecanut leaf sheath, coconut leaf sheath and coconut stem fiber) is showed here. FT-IR analysis of these fibers is also done for finding the difference of functional groups in the frequency domains of 4000-650 cm-1. Chemical analysis of fibers shows a comparative amount of chemical components such as aqueous extract, pectic matters, lignin, α–cellulose, hemicellulose, fatty and waxy matters in percent. Arecanut leaf sheath fiber represents the highest percent of α-cellulose. SEM analysis investigate the characteristics of the surface of the fibers. Correspondence to: Pinku Poddar, Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering and Technology, University of Dhaka, Bangladesh; E-mail: p.pinku@yahoo.com

Investigations of Titanium Implants Covered with Hydroxyapatite Layer

Abstract: To reduce unfavorable phenomena occurring after introducing an implant into human body various modifications of the surface are suggested. Such modifications may have significant impact on biocompatibility of metallic materials. The titanium and it's alloys are commonly used for joint and dental implants due to their high endurance, low plasticity modulus, good corrosion resistance as well as biocompatibility. Special attention should be given to titanium alloys containing zirconium, tantalum and niobium elements. These new generation alloys are used by worldwide engineering specialists. The experiments were performed with hydroxyapatite layer on titanium specimens with the use of electrophoresis method (different voltage and time).

Cavitation Erosion of P110 Steel in Different Drilling Muds

Abstract: The P110 steel specimens were subjected to ultrasonic cavitation erosion in different compositions of drilling muds and surfactant additive. The test procedure was based on ASTM-G-32 standard recommendations. API 5CT-P110 steel is used for pipes in oil and gas industry. The harsh environment and high velocity of flows poses corrosive and erosive threat on materials used there. The composition of drilling fluid influences its rheological properties and thus intensity of cavitation erosion. The erosion curves based on weight loss were measured.

Characterization of Coatings Created on Selected Titanium Alloys by Plasma Electrolytic Oxidation

Abstract: Abstract The SEM and EDS results of coatings obtained on pure niobium and titanium alloys (NiTi and Ti6Al4V) by Plasma Electrolytic Oxidation in the electrolytes containing of 300 g and 600 g copper nitrate in 1 litre of concentrated phosphoric acid at 450 V for 3 minutes, are presented. The obtained coatings are porous and consist mainly of phosphorus within titanium and copper. For each coating, the Cu/P ratios were calculated. The maximum of that coefficient was found for niobium and Ti6Al4V alloy oxidised in the electrolyte containing 600 g of Cu(NO3)2 in 1 dm3 of H3PO4 and equaling to 0.22 (wt%) | 0.11 (at%). The minimum of Cu/P ratio was recorded for NiTi and Ti6Al4V alloys oxidised by PEO in electrolyte consisting of 300 g of copper nitrate in 1 dm3 of concentrated phosphoric acid and equals to 0.12 (wt%) | 0.06 (at%). The middle value of that ratio was recorded for NiTi and it equals to 0.16 (wt%) | 0.08 (at%).

Energy-Dispersive X-Ray Spectroscopy Mapping of Porous Coatings Obtained on Titanium by Plasma Electrolytic Oxidation in a Solution Containing Concentrated Phosphoric Acid with Copper Nitrate

Abstract: Abstract The SEM and EDS study results of coatings obtained on titanium by Plasma Electrolytic Oxidation (PEO) in the electrolytes containing of 600 g copper nitrate in 1 liter of concentrated phosphoric acid at 450 V for 1 and 3 minutes, are presented. The obtained coatings are porous and consist mainly of phosphorus within titanium and copper. It was found that the time of PEO oxidation has impact on the chemical composition of the coatings. The longer time of PEO treatment, the higher amount of copper inside coating. The PEO oxidation of titanium for 1 minute has resulted in the creation of coating, on which 3 phases where found, which contained up to 13.4 wt% (9 at%) of copper inside the phosphate structure. In case of 1 minute PEO treatment of titanium, the 2 phases were found, which contained up to 13 wt% (8 at%) of copper inside the phosphate structure. The copper-to-phosphorus ratios after 1 minute processing belong to the range from 0.28 by wt% (0.14 by at%) to 0.47 by wt% (0.23 by at%), while after 3 minutes the same ratios belong to the range from 0.27 by wt% (0.13 by at%) to 0.35 by wt% (0.17 by at%). In summary, it should be stated that the higher amounts of phosphorus and copper were recorded on titanium after PEO oxidation for 3 minutes than these after 1 minute.

Effect of Concrete Addition of Selected Micro-fibers on the Reinforcing Bars Corrosion in the Reinforced Concrete Specimens

Abstract: Abstract The micro-fibers increase the consistency and uniformity of concrete, which can improve the protective properties of concrete cover and thus should reduce the corrosion of the reinforcement bars in the reinforced concrete elements. The article presents a study which main objective was to specify the effect on concrete mix the addition of steel or polypropylene micro-reinforcement fibers on the reinforcing bars corrosion process. The research included measuring the reinforcement corrosion progress caused by the chloride impact as well as cyclical freezing and thawing specimens test. To measure the electrochemical corrosion progress the non-destructive i.e. galvanostatic pulse method was used. The results were used to conduct a comparative analysis.

Optimization of Filler Metals Consumption in the Production of Welded Steel Structures

Abstract: Abstract The paper presents the some aspects of the optimization of filler metals consumption in the production of welded steel structures. Correct choice of beveling method can allow to decrease cost of production and increase quality. The review of calculation methods of filler metal consumption at the design stage was carried out. Moreover, the practical examples of amount of filler metals calculation were presented and analyzed. The article also contain examples of mobile apps which are makes it easy to see welding costs in just a few seconds. Apps as well as simple excel spreadsheets with correct mathematic equations allows to optimize welding process.

Mechanical Properties and Microstructure of Fast – Fired Clinker Tiles Based on Wierzbka I Raw Material

Abstract: Abstract The article presents results of research on microstructural and mechanical properties of floor tiles clinker manufactured on the basis of Wierzbka I raw material, which is part of the deposit Wierzbka, near Suchedniów. Wierzbka I clay was added in various volume fractions to the standard tile compositions used in industrial practice. The samples were pressed in a range of from 21 MPa to 42 MPa and fired in the laboratory furnace at 1130°C to 1190°C. Selected compositions were pressed at 28 MPa and fired in a standard industrial environment. The process of firing was conducted in an industrial kiln at temperature of 1160°C for 38 minutes, with holding for 4 minutes at maximum operating temperature. The samples, which were prepared in the laboratory and industrial conditions were evaluated for the effect of addition of the Wierzbka I clay on their microstructural and mechanical properties based on the measurement results of linear shrinkage, bulk density, open porosity, water absorption and flexural strength (Ϭ) of the tiles. Microstructural changes were observed with a scanning electron microscope (SEM). The results revealed that the tested tiles were characterized by a high degree of sintering, an apparent density of 2.5 g/cm3, an open porosity and water absorption below 0.5%. The measurement results of mechanical bending strength showed that the tested samples had a high strength of 50 MPa.

Polycarbonate/Polypropylene-Graft-Maleic Anhydride and Nano-Zeolite-Based Nanocomposite Membrane: Mechanical and Gas Separation Performance

Abstract: Abstract In this effort, blend membrane of polycarbonate (PC) and polypropylene-graft-maleic anhydride (PPMA) was fabricated via phase inversion technique. The nano-zeolite (NZ) was employed as nanofiller. Morphology of PC/PPMA/NZ membrane revealed unique inter-connected branched microstructure. Tensile strength and Young’s Modulus of PC/PPMA/NZ 0.1-5 were in the range of 59.9-74.5 MPa and 111.4-155.2 MPa respectively. The nano-zeolite filler was also effective in enhancing the permselectivity αCO2/N2 (23.5 to 38.5) relative to blend membrane (20.3). The permeability PCO2 of PC/PPMA/NZ 5 membrane was found as 106.2 Barrer. Filler loading enhanced gas diffusivity, however filler content did not significantly influence CO2 and N2 solubility.

Al2O3 + TiO2 Thin Film made by Electrostatic Spray Deposition

Abstract: Abstract In this work electrostatic spray deposition process was used to deposit thin Al2O3 + TiO2 ceramic thin film on X10CrAlSi18 steel from colloidal suspension of TiO2 powder in Al2O3 precursor solution. The precursor was 3% solution of Al2(NO3)3 in ethanol. An influence of the thermal treatment after film deposition on protective properties against high temperatures and film endurance were investigated. The resistance against thermal cycles and dynamic impacts were tested. Performed investigations showed that the best protective properties had the Al2O3 + TiO2 film sintered at 1000°C.

Examine bi-metallic rectangular thin walled tube under different trigger mechanisms

Abstract: Safety is the main design factor for any designer who creates or develops a new object. Involving aluminium to design the car longitudinal members has many benefits such as decreasing weight, decreasing the environment pollution and reducing fuel consumption. Bi-Metallic longitudinal member is created with both steel and aluminium materials. Four types of trigger have been modified, circular, elliptical, triangular and beaded to reduce the peak load and enhance the energy absorption values. Moreover, the percentage and position for the trigger geometry is studied. Circular trigger with 5% reduction was chosen as the best trigger due to enhancing energy absorption and reducing the peak load values. Correspondence to: Haidar Fadhil Al-Qrimli, Department of Mechanical Engineering, Curtin University, CDT 250 98009, Miri, Malaysia, Tel: +60 85 443939; Fax: +6085443837; E-mail: haidar.fa@curtin.edu.my

Surface analysis for signs of corrosion of fixed orthodontic appliances used in vivo

Abstract: Abstract The objective was to evaluate and assess the surface quality of fixed orthodontic appliances after intraoral usage for several months. Nine sets of orthodontic brackets by three different manufacturers and twelve archwires differing in chemical composition were analyzed in a scanning electron microscope with an energy dispersive X-ray analyzer for signs of corrosion. Obtained results showed that the majority of the evaluated appliances displayed no traces of corrosion. Machining or casting defects hardly ever act as the origins of corrosion processes. However, some samples displayed signs of corrosion of a galvanic and pitting nature. The authors claim, that despite the surface defects, most of the appliances were able to retain the desired corrosion resistance, although in some cases these flaws could act as the origin of corrosion processes.

Aortic Valve Geometry Modeling – Review

Abstract: Abstract The present work is a review of publications covering computer simulation of aortic valve operation and material properties of aortic valve components studies. Particular attention is paid to the anisotropy of material and geometric properties. The methods of geometric models developing by using specified research methods and/or diagnostic imaging devices are presented. The microstructure of the aortic valve is also described and its impact on material properties definition introduced. The various ways of describing the aortic valve leaflet anisotropic properties are mentioned. Often exploited simplifications and their impact on the simulation results is also presented.

Presence of bismuth in slag heap upcoming to a copper sample found in a Roman Siete Cuevas (Cerro Muriano, Córdoba (Spain))

Abstract: The detection, clearly, of the presence of up to 5% by mass of bismuth, in big drops of copper from a Roman era smelter, located near the Cerro de la Coja (Siete Cuevas) in Cerro Muriano (Córdoba); this assumes that some copper produced at this location in Roman times, containing bismuth. In previous studies by our research group, in such samples from the same archaeological site, the presence of this element was not detected. This fact, the presence of bismuth in a sample of copper in Cerro Muriano (Córdoba), it can mean the treatment of minerals from other sources, more or less far away, of this mining localitation. Correspondence to: Antonio J. Criado Portal, Department of Materials Science and Metallurgy Engineering, Faculty of Chemistry, Complutense University of Madrid, 28040 Madrid, Spain, E-mail: antoniocriado@quim.ucm.es

Factorial Design based Optimisation of Crevice Corrosion for Type 304 Stainless Steel in Chloride Solutions

Abstract: Abstract The effects of chloride concentration, creviced scaling factor and immersion time on the percentage area and maximum depth of attack for Type 304 stainless steel (SS304) in chloride solutions were investigated. The crevice assembly comprised of coupon (SS-304), polytetrafluoroethylene (crevice former) and fasteners (titanium bolt, nut and washers). The full immersion tests were based on ASTM G-78 using full factorial design to study the effects of chloride concentration (1.5, 3.0 and 4.5 w/w%), crevice scaling factor (8, 16 and 24) and immersion time (15, 30 and 45 days) on the percentage area of attack (Y1) and maximum depth of attack (Y2) of SS-304. Data obtained was used to develop and optimize the models of Y1 and Y2 in terms of the three factors using Response Surface Methodology (RSM). The R2 of Y1 and Y2 were 0.98 and 0.91, respectively. The minimum Y1 (5.63%) and Y2 (3.32×10−7 mm) were obtained at 4.5% chloride concentration, 20 scaling factor and 15 days immersion time. The predicted optimal conditions agreed with the experimental results for validation with a maximum absolute relative error of 5.75%.

Effect of Long Term Service at Elevated Temperatures on Mechanical Properties of Manaurite XM Reformer Tubes

Abstract: Microstructure transformations occur in the Manaurite XM cast steel tubes during long-term operation in the reformer furnace were revealed and described. The rela tionship between mechanical properties, an increase of internal diameter of the tube and microstructure degradation is discussed. Static tensile test was performed on two types of samples with different shapes. It has been shown differences in the results of tests and an explanation of this phenomenon.

On the Durability of the Hydraulic Satellite Motor Working Mechanism in Overload Condition

Abstract: The paper presents the newest construction of the hydraulic satellite pump/motor. In this study, the fracture of the hydraulic satellite motor working mechanism is investigated. Factors influencing the durability of satellite working mechanism have been described. The durability of the hydraulic satellite motor working mechanism at a load, corresponding to a pressure of 15 MPa supplied with refined rapeseed oil is very low. Analyses of construction and laboratory tests showed that the satellites teeth wear out the fastest. Results showed that bending fatigue and surface contact fatigue of the satellites are the main cause of the hydraulic satellite motor working mechanism failures.

Influence of Nitriding and Laser Remelting on Properties of Austenitic Stainless Steel Type X10CrNi18-8 and Cavitation Erosion Resistance

Abstract: The paper presents properties of surface layers. Surface layers were obtained by using low temperature glow–discharge nitriding process and laser remelting carried out on austenitic stainless steel type X10CrNi18-8. Investigations were done by using an Ultra Nanoindentation Tester (UNHT) in the Warsaw Institute of Fundamental Technological Research. The influence of the above mentioned treatments on obtained surface layers is shown. The values of the Vickers hardness (HV), the irreversible indentation work (Wir), the reversible work (We) and the maximum depth (hmax) during indentation were determined using the method proposed by Oliver and Pharr [1]. On the basis of mechanical properties, the elasticity (Ie) and ductility (Iir) indexes were calculated. Moreover, microstructure cross-section of the austenitic stainless steel after nitriding process and laser remelting was observed using a scanning electron microscope. Cavitation test was performed at a vibratory rig with stationary specimen. On the basis of erosion curves the cavitation resistance was evaluated. Influence of Nitriding and Laser Remelting on Properties of Austenitic Stainless Steel Type X10CrNi18-8 and Cavitation Erosion Resistance. Available from: https://www.researchgate.net/publication/305842249_Influence_of_Nitriding_and_Laser_Remelting_on_Properties_of_Austenitic_Stainless_Steel_Type_X10CrNi18-8_and_Cavitation_Erosion_Resistance [accessed Dec 2, 2016].

Specificity of polyclonal antibody-based magnetostrictive biosensors

Abstract: Magnetoelastic (ME) biosensors were developed by immobilizing polyclonal antibody using Langmuir-Blodgett (LB) technique onto a magnetostrictive platform, which can offer wireless and remote detecting, a unique advantage over conventional sensor platforms. Due to the magnetoelastic nature of the amorphous magnetostrictive alloy, the sensor exhibits a physical resonance when it undergoes a time-varying magnetic field, a shift in resonance frequency occurs when its mass changes due to bacteria binding, and the bound bacterial cells were visibly confirmed by scanning electron microscopy (SEM) micrographs, then the density of bacteria bound on the biosensor was calculated. The specificity to detect different kinds of bacteria, including Salmonella species and non- Salmonella species was studied. The results show that the prepared polyclonal antibodybased biosensor shows excellent specificity to detect bacteria of Salmonella species, and especially prefers to bind Salmonella typhimurium, almost zero affinity for non- Salmonella species of Listeria monocytogenes.