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Corrosion, in conjunction with chemical, thermal, and stress-related factors, results in long-term issues for ships and submarines that are subjected to corrosive environments. Marine components are vulnerable to corrosion, which may lead to costly repairs. Applying coatings and subjecting aluminium components to heat treatment might successfully prevent corrosion. There has been much global research into corrosion processes, and technologies have been developed to determine the extent of corrosion damage to reinforcement. The purpose of this study is to provide a concise synopsis of corrosion prevention coatings and corrosion processes. [ABSTRACT FROM AUTHOR]

An impeller a rotating component used to increases or decreases the flow and pressure of fluids, which has wide spread applications in aircraft sector, automobile industry, medical field and power plant technology. In real time applications bronze and hardened steel impellers quickly erode when presented to destructive mediums, for example, waste water, seawater, sewage,, chlorine, bromine, and numerous chemicals. They are dependent upon cavitation and electrolysis (galvanic erosion) which rashly demolishes the impeller drastically. The corrosion is the major problem of the impeller that increases pump operating and maintenance expenses which obligated the industries to search for alternative materials. The main criterion is to select the appropriate selection of material for the impeller to resist corrosion. Materials such as Caprolone (Nylon) and ABS (Acrylonitrile Butadiene Styrene) have been consider for the study considered which has chemical, thermal stability along with toughness and strength. The design and analysis of impeller is designed, analyzed using commercially available simulation tools. [ABSTRACT FROM AUTHOR]

In recent years, Rapid Tooling (RT) and Additive Manufacturing (AM) have been implemented in many aspects of the industry, especially in the area of new product development. The demands for short time delivery of lowcost products with various geometrical shapes show an increasing trend from year to year. With the increasing number of plastic and rubber products manufacturers as well as engineering, product fabricators, the need for low cost materials and cheap tooling, including RT has also increased. Manufacturers are sorting for new and cheap materials, both for the components as well the manufacturing techniques. The advancement of AM and RT technologies had shown drastic improvement in the technologies and the materials being processed. The replacement of pure material to metal epoxy composite with the addition of filler particle because of global demand for economical, lightweight, high performance, and wear and corrosion resistant materials. However, the tooling materials for fabrication of mold and die using RT techniques are still limited, especially on metal epoxy composite material. [ABSTRACT FROM AUTHOR]

Polyester-glass fiber treated silane coupling agent coatings had been successfully developed to investigate the corrosion inhibition of steel by modifying Polyester-Glass Fiber as Primer coating. The Tafel polarization measurement and immersion test was done to determine the corrosion properties of the coatings with different types of loading (0-40%). Corrosion rate was declined with the addition of glass fibers at 10% of loadings which is 0.77735 mmpy, due to the addition of glass fiber-silane coupling agent acted as corrosive inhibitor. However, further increase in glass fiber loadings shows a decrement in the corrosive properties due to poor interaction between the constituents. The addition of glass fiber-silane coupling agent has great potential to combat corrosive properties in polyester primer coatings application. [ABSTRACT FROM AUTHOR]

Corrosion behaviors of heat-resistant superalloy HAYNES 120 in a simulated ash environment at 750°C and 810°C were investigated. XRD, SEM, EDS were employed to characterize the corrosion products. Results show that corrosion kinetics of experimental materials followed a parabolic corrosion law. A uniform Cr2O3 film formed on the surface of Haynes 120 without simulated ash. Only the oxide layer formed at 810°C after 1000h is spalled. The oxide layer formed in simulated ash consisted of (Mn, Ni)Cr2O4 and Fe2O3 after 75°Cand 81°C,respectively. It can be concluded Cr and Ni improved the resistance of HAYNES 120 in high temperature simulated ash environment. The Fe content in HAYNES 120 can be a restricted factor for the corrosion resistance. [ABSTRACT FROM AUTHOR]

Titanium coatings are very attractive to several industrial fields, especially aeronautics, due to the enhanced corrosion resistance and wear properties as well as improved compatibility with carbon fiber reinforced plastic (CFRP) materials. Cold sprayed titanium coatings, among the others deposition processes, are finding a widespread use in high performance applications, whereas post-deposition treatments are often used to modify the microstructure of the cold-sprayed layer. Laser treatments allow one to noticeably increase the superficial properties of titanium coatings when the process parameters are properly set. On the other hand, the high heat input required to melt titanium particles may result in excessive temperature increase even in the substrate. This paper introduces a thermo-mechanical model to simulate the laser treatment effects on a cold sprayed titanium coating as well as the aluminium substrate. The proposed thermo-mechanical finite element model considers the transient temperature field due to the laser source and applied boundary conditions using them as input loads for the subsequent stress-strain analysis. Numerical outcomes highlighted the relevance of thermal gradients and thermally induced stresses and strains in promoting the damage of the coating. [ABSTRACT FROM AUTHOR]

This paper describes the methods of obtaining hydrides of rare earth elements such as dysprosium and neodymium. The properties and corrosion resistance of these elements are investigated. A synthesis method of monophasic dysprosium and neodymium dihydrides is presented. Synthesized dihydrides are agglomerates with an average size of 3-50 µm and are formed by crystalline grains of a nanometer size. BET specific surface area, morphology, elemental analyses and composition of samples have been studied. Corrosion stability in aqueous solutions of hydrochloric acid and sodium hydroxide were studied. It was determined that both hydrides undergo hydrolysis in acid and alkaline mediums. Neodymium hydride is more stable to corrosion than dysprosium hydride, which is proved by its longer exposure to aggressive medium to hydrides. The formation of insoluble /poorly soluble products of corrosion can make a significant contribution to the process of powder dissolution. [ABSTRACT FROM AUTHOR]

Tungsten carbide based coating has been well known as wear and corrosion resistance materials. However, less study is done on comparing the coating with different binder. Thus, in this work the wear and corrosion behaviour of high velocity oxy-fuel (HVOF) coatings, namely (i) tungsten carbide cobalt and (ii) tungsten carbide nickel will be evaluated. Both coatings were characterised using X-ray Diffractometer (XRD) and Scanning Electron Microscope (SEM). The wear behaviour has been examined using the modified grinder machine by weight loss measurement. Two types of abrasive have been used that include 3 g by weight alumina and silica. While for the corrosion behaviour, it is monitored by three electrodes of electrochemical test and immersion test for 30 days in an acidic environment. The electrolyte used was 0.5 M sulphuric acids (H2SO4). It was found that the cobalt binder shows higher wear resistance compares to the nickel binder for both slurry types. The harder alumina compared to silica results in higher wear rate with removal of carbide and binder is about the same rate. For silica abrasive, due to slightly lower hardness compared to the carbide, the wear is dominated by binder removal followed by carbide detachment. For corrosion, the nickel binder shows four times higher wear resistance compared to the cobalt binder as expected due to its natural behaviour. These finding demonstrate that the selection of coating to be used in different application in this case, wear and corrosion shall be chosen carefully to maximize the usage of the coating. [ABSTRACT FROM AUTHOR]

FRP material has good characteristics such as light-weight, high-strength and high-corrosion resistance. Lightweight structure possesses some advantages over the rational constructing procedure such as self-building structures. In recent years, mechanical characteristics of FRP joints using bolts and/or rivet are investigated in detail, and they are used in many FRP structures. However, the bolts lack bearing strength compared with material strength and the joint needs the prepared bolt hole. In this paper, an alternative joint system for FRP structures using tapping screw is proposed and mechanical characteristics are investigated through experiment. Tapping screw has some advantages; easy-to-use, lightweight and high bearing strength. Then, the results of double-lapped tensile shear tests having one, four and eight tapping screws along longitudinal direction are shown. Moreover, it is shown that longitudinal stress distribution is approximately corresponding to the theoretical stress distribution of double-lapped adhesively bonded joints. Based on these, it is proposed that joint strength can be estimated by using the present calculation method. [ABSTRACT FROM AUTHOR]

Zn-Al-Mg-RE hot-dip alloy coatings which prepared by the environmentally friendly plating auxiliary were investigated by X-ray diffraction (XRD), SEM analysis and salt spray measurement. Significant variation in coating surface morphology and element content are observed with increasing content of Al and Mg in this paper. A reinforced ternary eutectic Zn-Al-MgZn2 is confirmed which attribute to improvement metallographic structure derived from certain ternary eutectic reaction in alloy solidification. For Mg-containing coatings, the enhanced corrosion resistance is observed by corrosion resistance test in salt spray at 35°C with 5% NaCl in terms of corrosion weight changes. It is found that the incorporation of 3 wt.% Mg and 0.1 wt.% rare earth element in to Zn-Al-Mg-RE bath caused structural refinement of the crystal and also helped to achieve excellent surface morphology. [ABSTRACT FROM AUTHOR]

This paper presents features and heterogeneity of yielding at micro- and macro-scale levels of corrosion-resistant bimetal based on a compound of austenitic stainless steel (301 AISI) and low-carbon construction steel (A 283 Grade C) using the methods of scanning-electron, atomic force and optical microscopy. The staging of stress-strain curves was analyzed. [ABSTRACT FROM AUTHOR]

The local mechanical properties of the laser-welded joint of the VT1-0 titanium alloy and the 12Cr18Ni10Ti stainless steel with an intermediate copper insert are studied in the paper. It is shown that this mode provides for an intensive diffusion interaction of the materials to be joined and the copper plate, allows obtaining a smooth change in the chemical composition, and is characterized by the scatter of the mechanical properties in the bulk of the joint. [ABSTRACT FROM AUTHOR]

In this work we focus on characterization of LC200N steel by back-scattering Mössbauer spectrometry (MS). This geometry was used due to high sample thickness (0.5 mm). MS is a method suitable for determination of iron compounds and their properties in steels. We investigated samples with three different thermal treatments: non-hardened, hardened, and hardened with subsequent rapid quenching. Disk-shaped samples were cut off from original rods and polished from one side. The effect of surface treatment was investigated, too. Variations in microstructure imposed by different thermal and surface treatments were unveiled by Mössbauer parameters of backscattering spectra taken from both sides of the investigated samples. In this way, differences between the original as-cut and polished surfaces of the disks were unveiled. [ABSTRACT FROM AUTHOR]

A change in the dimensions of a specimen vs. the reference size can affect fatigue properties of a material. This phenomenon is referred to as the "size effect". The study concerned checked how this effect can influence non-alloy steels S235JR, S355J2+C and acid-resistant steel 1.4301. Two specimen sizes and two load types were tested. Selected models of the size effect were verified to estimate fatigue strength for a cross-sectional area other than the one obtained experimentally. [ABSTRACT FROM AUTHOR]

This study experimentally evaluated the effect of Sodium Nitrate inhibitor (NaNO3) of 0.1%, 0.3%, and 0.5% on NaCl 3.5% toward pitting corrosion of dissimilar metal welding joint between stainless steel AISI 304 and mild steel SS 400. Electrochemical corrosion was tested using potentiodynamic polarization. Further the Scanning Electron Microscope (SEM) conducted to analyze the specimen. Chemical composition analysis used Energy Dispersive X-ray Spectrometry (EDS). The highest efficiency of sodium nitrate for ER 308 attained 63.8% and 64.89%for ER 309L. The specimen surface which observed through SEM showed decrease of pitting corrosion respectively with the addition of sodium nitrate content as inhibitor. [ABSTRACT FROM AUTHOR]

Duplex stainless steel (DSS) is a two-phase (ferrite and austenite) material, which exhibits an attractive combination of mechanical properties and high corrosion resistance, being commonly employed for equipment of petrochemical plants, refining units and oil & gas platforms. The best properties of DSS are achieved when the phases are in equal proportions. However, exposition to high temperatures (e.g. welding process) may entail undesired consequences, such as deleterious phases precipitation (e.g. sigma, chi) and different proportion of the original phases, impairing dramatically the mechanical and corrosion properties of the material. A detailed study of the magnetic behavior of DSS microstructure with different ferrite austenite ratios and deleterious phases content was accomplished. The non destructive method evaluates the electromagnetic properties changes in the material and is capable to identify the presence of deleterious phases into DSS microstructure. [ABSTRACT FROM AUTHOR]

The Nuclear Regulatory Commission regulates approximately 100 commercial nuclear power reactor facilities that contribute about 20% of the total electric energy produced in the United States. Half of these reactor facilities are over 30 years old and are approaching their original design service life. Due to economic and durability considerations, significant portions of many of the facilities were constructed with reinforced concrete, including the containment facilities, cooling towers, and foundations. While most of these concrete facilities have performed exceptionally well throughout their initial expected service life, some are beginning to exhibit different forms of concrete deterioration. In this study, acoustic emission (AE) is used to monitor two main concrete deterioration mechanisms; alkali-silica reaction (ASR) distress and corrosion of reinforcing steel. An accelerated ASR test was conducted where specimens were continuously monitored with AE. The results show that AE can detect and classify damage due to ASR distress in the specimens. AE was also used to remotely monitor active corrosion regions in a reactor facility. AE monitoring of accelerated corrosion testing was also conducted on a concrete block specimen cut from a similar reactor building. Electrochemical measurements were conducted to correlate AE activity to quantifiable corrosion measurements and to enhance capabilities for service life prediction. [ABSTRACT FROM AUTHOR]

Since March 2010 the preliminary design of the ITER ICRF Antennas have been developed by CYCLE, a consortium consisting of IPP (Garching), CCFE (Culham), CEA (Cadarache), Politecnico di Torino (Torino) and LPPERM/ KMS (Brussels). This paper describes the steps taken to develop the present geometry of the triplet pair Strap Housing Module from a thermal and structural perspective, and shows the critical areas of the structure. Key issues are the manufacturability, (achieved by HIPing - Hot Isostatic Pressing), the ability to handle the radiating plasma thermal flux of 0.35 MW/m2, the RF losses and the neutronic radiation. HIPing is necessary to achieve the complicated system of cooling channels inside the structure, which divides the coolant equally in order to supply each strap in the triplet with 1 l/s of water. The components have also to withstand the strong mechanical forces generated by plasma disruptions affecting all internal structures and the elevated design cooling water pressure of 5MPa. In order to maximise reliability, joints between different materials in the cooling water system have been kept to a minimum. Therefore, in the interests of fabricability and availability, the whole structure is manufactured out of stainless steel (316L(N)IG). The low conductivity of 316L(N)IG demands small wall thicknesses to avoid hot spots; however this reduces the mechanical strength. Consequently an in depth FEM analysis is presented, which was used to find and to improve the critical aspects of this important component and was the best means of finding the optimum between thermal and mechanical performance. [ABSTRACT FROM AUTHOR]

Graphite is a widely used structural material for high temperature and high vacuum applications in furnaces handling corrosive materials or plasmas. The porosity, density, dimensions, impurities along with the history of graphitization, handling and storage of graphite dictate the outgassing characteristics. Graphite plates of density 1.78 g/cc were outgassed up to 1200 °C in vacuum of the order of 5×10-5 mbar in an in-house facility. A sample of the degassed graphite was taken for Thermo-Gravimetric Analysis (TGA). The TGA of the outgassed sample shows continuous weight loss in the temperature range of 200 °C to 1200 °C, indicating a much higher temperature is required for complete removal of gases. However, it may be noted that total outgassing is a function of the dimensions of the sample. The small coupon used in the TGA studies may not exactly replicate the large graphite blocks that outgases from the surface as well as from the bulk. The behaviour of graphite plates used in the liquid metal handling furnace where the graphite was finally used further confirmed this observation. The outgassing shown by the degassed graphite can be attributed to the diffusion of the absorbed gases from the bulk as well as desorption of the chemisorbed species which requires higher activation energies and higher temperature. [ABSTRACT FROM AUTHOR]

Laser Shock Processing is developing as a key technology for the improvement of surface mechanical and corrosion resistance properties of metals due to its ability to introduce intense compressive residual stresses fields into high elastic limit materials by means of an intense laser driven shock wave generated by laser with intensities exceeding the 109 W/cm2 threshold, pulse energies in the range of 1 Joule and interaction times in the range of several ns. However, because of the relatively difficult-to-describe physics of shock wave formation in plasma following laser-matter interaction in solid state, only limited knowledge is available in the way of full comprehension and predictive assessment of the characteristic physical processes and material transformations with a specific consideration of real material properties. In the present paper, an account of the physical issues dominating the development of LSP processes from a moderately high intensity laser-matter interaction point of view is presented along with the theoretical and computational methods developed by the authors for their predictive assessment and new experimental contrast results obtained at laboratory scale. [ABSTRACT FROM AUTHOR]

Corrosion, erosion and plugging of the downstream equipments by tar and ash particle and, low energy content of syngas are the main problems of biomass gasification process. This paper attempts to review the findings of literature on the effect of temperature on syngas quality, and in alleviating the tar and ash problems in the gasification process. The review of literature indicates that as the gasification temperature increases, concentration of the resulting H2 and carbon conversion efficiency increase, the amount of tar in the syngas decreases. For the same condition, CH4 and CO concentration do not show consistent trend when the feedstock and gasification process varies. These necessitate the need for conducting an experiment for a particular gasification process and feedstock to understand fully the benefits of controlling the gasification temperature. This paper also tries to propose a method to improve the syngas quality and to reduce the tar amount by using preheated air and superheated steam as a gasifying media for oil palm fronds (OPF) gasification. [ABSTRACT FROM AUTHOR]

The present aim of this study is to determine the corrosion effect of palm oil methyl ester (POME) on aluminium alloy 5083 (AA5083). The static immersion test was carried out at 60°C for 68 days according to ASTM G-31-72. The corrosion analysis was done by using weight loss method and electrochemical test. The POME was analyzed by using Fourier Transform Infrared (FTIR) to determine its functional group. The result from weight loss method shows the decreasing in weight loss of AA5083 which signifies the ability of POME to reduce corrosion rate. The electrochemical test shows the decreasing in polarization resistance, Rp while the corrosion current densities, icorr increase. The corrosion rate reduces from 2.250mpy to 0.1946mpy. The low concentration of fatty acid C18:2 and high anti oxidant element contributes to the reduction of corrosion rate of AA5083 in POME. [ABSTRACT FROM AUTHOR]

Pack chromizing and aluminizing has been widely used for many years to improve hot temperature oxidation and corrosion resistance of metals. The coating process involves packing the steel in a powder mixture which contain aluminum and chromium source, and inert filler (usually alumina), and halide activator NH4Cl. Al and Cr were deposited onto carbon steel by pack cementation process using elemental Al and Cr powder as Al and Cr source, whereas NiCo alloys codeposited by electrodeposition. The position of Al and Cr could be under or over Ni-Co alloys deposited. Pack cementation was heated on dry inert gas at temperature 800 °C about 5 hours and 20 minute for Cr and Al respectively. Al and Cr was successfully deposited. Laying down effect of Al and Cr onto carbon steel whether up and down toward NiCo alloys coating have affected to oxidation resistance. The pack aluminizing as top layer given best resitance to restrain excessive oxide scale, in contrast pack chromizing reveal bad oxidation resistance, moreover occured spallation on layer. [ABSTRACT FROM AUTHOR]

MP35N is a Nickel-Cobalt based superalloy that currently has numerous applications at both room and elevated temperatures due to its ultra high strength, high modulus and outstanding corrosion resistance. The National High Magnetic Field Laboratory (NHMFL) further explored the use of MP35N in cryogenic temperature applications. Currently, the material is used as a structural reinforcement component for high field pulsed magnets operating at 77 K. The NHMFL is also pursuing the application of MP35N below 77 K, such as either reinforcement or substrates for high-temperature superconducting (HTS) magnets operating at 4.2 K. This paper reports the tensile properties of cold-rolled and aged MP35N at room temperature, liquid nitrogen and liquid helium temperatures. Optimized fabrication methods developed by the NHMFL and H.C. Starck have improved the material's cryogenic properties with ultimate tensile strengths exceeding 2500 MPa and a modulus of elasticity higher than 200 GPa. Closer examination of the stress-strain curve reveals that the material exhibits internal stress which is attributed to the development of nanoplatelets during the fabrication process. [ABSTRACT FROM AUTHOR]

The study of characteristic material structure is the important issue to understand the phenomena of corrosion. Molecular dynamic simulation has been carried out for studying the surface interaction between stainless steel and coolant material Lead-Bismuth (Pb-Bi) in several temperatures. The material with complex molecular interactions has a long simulation process that needs parallel processing in cluster system. MOLDY is an open source program which can be used to mono atomic or polyatomic in cluster computer. This paper will discuss the effect of Molybdenum (Mo) on the corrosion with Mo 2%-3% and Mo 3%-4% in several temperatures. The simulation is done between crystals steel Fe 71%, Ni 10% and Cr 16% with Mo 2%-3% and Fe 70%, Ni 10%, Cr 16% with Mo 3%-4%. The effect of increasing Mo content in crystal steel for resistance corrosion will be presented in this paper. The results of this simulation show that the phenomena of Mo with difference content on the corrosion in several temperatures. That can be used to identify whether the system has resistance corrosion or not. This simulation obtain that the surface of stainless steel by lead-bismuth Pb-Bi with Mo 3%-4% content has less corrosion than the surface of stainless steel with Mo 2%-3% content. This phenomenon has the same with the statement from experiment that the stainless steel with Mo 3%-4% content has corrosion resistance than the stainless steel with Mo 2%-3% content. [ABSTRACT FROM AUTHOR]

In this present work, we report numerical results of iron (cladding) corrosion study in interaction with lead-bismuth eutectic coolant of advanced nuclear reactors. The goal of this work is to study how the oxygen can be used to reduce the corrosion rate of cladding. The molecular dynamics method was applied to simulate corrosion process. By evaluating the diffusion coefficients, RDF functions, MSD curves of the iron and also observed the crystal structure of iron before and after oxygen injection to the coolant then we concluded that a significant and effective reduction can be achieved by issuing about 2% number of oxygen atoms to lead-bismuth eutectic coolant. [ABSTRACT FROM AUTHOR]

The recent progress of the studies related to lead alloy-cooled reactors (LFR) and the accelerator driven system (ADS) is summarized. The compatibility of materials with lead alloys has been clarified under steady and transient temperature conditions. Higher Cr content, Si and Al addition and Al-Fe alloy-coating improved the corrosion resistance of steels. The Al-Fe alloy-coated steel was not corroded even under high temperature transient conditions. The ceramics of SiC and Si3N4 are expected to be used as cladding material for high temperature LFR. For the analytical consideration of mass transport in lead alloy circuit, the diffusion coefficient of Ni was measured using the capillary methods. A new bubble visualization method in LBE using gamma-ray radiography was developed. The thermal interaction of lead-bismuth eutectic (LBE) and lead droplets with sub-cooled water, and the behaviors of droplet fragmentation were investigated, and the visualization of volatile liquids in high temperature liquids was achieved. [ABSTRACT FROM AUTHOR]

Corrosion is one of the industries major issues regarding the integrity of assets. Currently inspections are conducted at regular intervals to ensure a sufficient integrity level of these assets. Cost reduction while maintaining a high level of reliability and safety of installations is a major challenge. The concept of predictive maintenance using permanent sensors that monitor the integrity of an installation matches very well with the objective to reduce cost while maintaining a high safety level. Guided waves are very attractive for permanent monitoring systems because it provides a wall thickness map in between two sensor rings. The wall thickness map provides quantitative information about the remaining wall thickness, location and extent of the corrosion. The performance of guided wave tomography has been evaluated experimentally assessing the sizing accuracy and the smallest corrosion spots that can be detected with this technology. The results show accurate sizing, with a sizing accuracy better than 10% of the nominal wall thickness. Additionally, the maximum distance between the transmitter and receiver rings and the presence of different coatings has been evaluated. The results demonstrate the robustness of the technology under a range of practical conditions. [ABSTRACT FROM AUTHOR]

Failures in boiler waterwalls can occur when a relatively small amount of corrosion and loss of metal have been experienced. This study presents our efforts towards the application of Line Scanning Thermography (LST) for the analysis of thinning in boiler waterwall tubing. LST utilizes a line heat source to thermally excite the surface to be inspected and an infrared detector to record the transient surface temperature increase observed due to the presence of voids, thinning or other defects. In waterwall boiler tubes the defects that can be detected using LST correspond to corrosion pitting, hydrogen damage and wall thinning produced by inadequate burner heating or problems with the water chemistry. In this paper we discuss how the LST technique is implemented to determine thickness from the surface temperature data, and we describe our efforts towards developing a semiautomatic analysis tool to speed up the time between scanning, reporting and implementing repairs. We compare the density of data produced by the common techniques used to assess wall thickness and the data produced by LST. [ABSTRACT FROM AUTHOR]

The aim of this work was to investigate fracture toughness and corrosion resistance of semisolid AlSi5 castings, compared to samples obtained from conventional casting operations. In order to have a semisolid microstructure, the melt alloy was treated by means of ultrasound during solidification and then poured into permanent moulds. Mechanical properties of semisolid and conventional castings were compared by means of ultimate tensile strength (Rm), yield stress (Rp02) and hardness (HV) measurements. Fracture mechanics tests were carried out on Single Edge Notched Bend (SENB) specimens, machined from castings, and pre-cracked by fatigue. These tests were performed to determine the effect of the microstructure on the J-Integral resistance (J-R) behavior and to deeply understand the ductile fracture behaviour of semisolid parts. The J-Integral versus spaced crack extension (J-Δa) curves showed an improved resistance of the semisolid microstructure, due to the higher ductility. Finally, the corrosion behaviour of semisolid samples was compared to that of castings coming from solidification of fully liquid alloy by means of electrochemical potentiodynamic polarization tests. It was observed that the globular microstructure offers better quality, in terms of higher mechanical properties, as a consequence of a more uniform distribution of the solute. [ABSTRACT FROM AUTHOR]

Titanium and its alloys are nowadays widely used in many sectors: in the medical field (orthopedic and dental ones), in the architectural field, in the chemical plants field and in aeronautic. In this last field it is more and more used both for its contribution to make lightweight and time durable structures and for its compatibility with new materials, first of all Carbon Fiber Reinforced Plastics (CFRP). To this aim, lots of researches are now focusing on new and emerging technologies capable to make titanium objects and, at the same time, reducing the scrap, since titanium alloys for aeronautic application are very expensive. This paper examines Grade 5 Titanium Alloy (Ti6Al4V) welded by Laser Beam (LBW) in butt-joint configuration. The source was Nd:YAG laser, moreover two inert gases were used, in order to provide a shield both on the top and on the bottom of the weld bead. The joints were studied by varying two process parameters: welding speed and power of the laser beam. It was not possible to realize a full experimental plan, due to technological limits in making titanium laser beam welds. The joints were tested to measure their mechanical properties and the corrosion resistance. The process parameters do not significantly affect the maximum static strength of the joints. Microscopic analysis showed that welds made with high power and low welding speed have a uniform weld bead, and no macroscopic defect occurs. Fatigue test results, instead, show a marked influence of the morphology of the weld bead: the occurrence of some defects, such as the undercut, both on the top and on the bottom of the weld bead, dramatically reduced fatigue resistance of the joints. Corrosion resistance was studied using the electrochemical micro cell technique, which allows to distinguish electrochemical properties of each zone of the weld bead, even when, as in this case, they are very narrow. By a general point of view, it has been demonstrated that the joints showing the best mechanical performances also possess better electrochemical properties. What's more, in these cases, the weld bead shows a cathodic behavior with respect to the parent material. [ABSTRACT FROM AUTHOR]

Limited natural resources increase the demand on highly efficient machinery and transportation means. New energy-saving mobility concepts call for design optimisation through downsizing of components and choice of corrosion resistant materials possessing high strength to density ratios. Component downsizing can be performed either by constructive structural optimisation or by substituting heavy materials with lighter high-strength ones. In this context, forging plays an important role in manufacturing load-optimised structural components. At the Institute of Metal Forming and Metal-Forming Machines (IFUM) various innovative forging technologies have been developed. With regard to structural optimisation, different strategies for localised reinforcement of components were investigated. Locally induced strain hardening by means of cold forging under a superimposed hydrostatic pressure could be realised. In addition, controlled martensitic zones could be created through forming induced phase conversion in metastable austenitic steels. Other research focused on the replacement of heavy steel parts with high-strength nonferrous alloys or hybrid material compounds. Several forging processes of magnesium, aluminium and titanium alloys for different aeronautical and automotive applications were developed. The whole process chain from material characterisation via simulation-based process design to the production of the parts has been considered. The feasibility of forging complex shaped geometries using these alloys was confirmed. In spite of the difficulties encountered due to machine noise and high temperature, acoustic emission (AE) technique has been successfully applied for online monitoring of forging defects. New AE analysis algorithm has been developed, so that different signal patterns due to various events such as product/die cracking or die wear could be detected and classified. Further, the feasibility of the mentioned forging technologies was proven by means of the finite element analysis (FEA). For example, the integrity of forging dies with respect to crack initiation due to thermo-mechanical fatigue as well as the ductile damage of forgings was investigated with the help of cumulative damage models. In this paper some of the mentioned approaches are described. [ABSTRACT FROM AUTHOR]

Titanium alloys offer superb properties in strength, corrosion resistance and biocompatibility and are commonly utilized in medical devices and implants. Micro-end milling process is a direct and rapid fabrication method for manufacturing medical devices and implants in titanium alloys. Process performance and quality depend upon an understanding of the relationship between cutting parameters and forces and resultant tool deflections to avoid tool breakage. For this purpose, FE simulations of chip formation during micro-end milling of Ti-6Al-4V alloy with an ultra-fine grain solid carbide two-flute micro-end mill are investigated using DEFORM software. At first, specific forces in tangential and radial directions of cutting during micro-end milling for varying feed advance and rotational speeds have been determined using designed FE simulations for chip formation process. Later, these forces are applied to the micro-end mill geometry along the axial depth of cut in 3D analysis of ABAQUS. Consequently, 3D distributions for tool deflections & von Misses stress are determined. These analyses will yield in establishing integrated multi-physics process models for high performance micro-end milling and a leap-forward to process improvements. [ABSTRACT FROM AUTHOR]

Machining of Ti-6Al-4V ELI becomes more interested topic due to extremely weight-to-strength ratio and resistance to corrosion at elevated temperature. Quality of machined surface is presented by surface roughness, surface texture and damages of microstructure of titanium alloys. The turning parameters evaluated are cutting speed of 55-95 m/min, feed rate of 0.15-0.35 mm/rev, depth of cut of 0.10-0.20 mm and tool grade of CVD carbide tools. The results show the trend lines of surface roughness value are higher at the initial machining and the surface texture profile has a strong correlation with the feed rate. At the machining condition of cutting speed of 95 m/min, feed rate of 0.35 mm/rev and depth of cut of 0.10 mm produced the with layer with thickness of 2.0 μm. [ABSTRACT FROM AUTHOR]

The purpose of this study is to produce composite plates by explosive cladding process. This is a process in which the controlled energy of explosives is used to create a metallic bond between two similar or dissimilar materials. The welding conditions were tailored through parallel geometry route with different operational parameters. In this investigation, a two-pronged study was adopted to establish the conditions required for producing successful solid state welding: (a) Analytical calculations to determine the weldability domain or welding window; (b) Metallurgical investigations of explosive welding experiments carried out under different explosive ratios to produce both wavy and straight interfaces. The analytical calculations confirm the experimental results. Optical microscopy studies show that a transition from a smooth to wavy interface occurs with an increase in explosive ratio. SEM studies show that the interface was outlined by characteristic sharp transition between two materials. [ABSTRACT FROM AUTHOR]

Inexpensive and conductive materials termed as stainless steel mesh and polyvinylidene fluoride (PVDF)-graphite were currently used as the air cathode electrodes in MFCs for the investigation of power production. By loading PTFE (poly(tetrafluoroethylene)) on the surface of stainless steel mesh, electricity production reached 3 times as high as that of the naked stainless steel. A much high catalytic activity for oxygen reduction was exhibited by Pt based and PTFE loading stainless steel mesh cathode, with an electricity generation of 1144±44 mW/m2 (31±1 W/m3) and a Coulombic efficiency (CE) of 77±2%. When Pt was replaced by an inexpensive transition metal based catalyst (cobalt tetramethylphenylporphyrin, CoTMPP), power production and CE were 845±21 mW/m2 (23±1 W/m3) and 68±1%, respectively. Accordingly, power production from PVDF-graphite (hydrophobic) MFC and PVDF-graphite (hydrophile) MFC were 286±20 mW/m2(8±1 W/m3) and 158±13 mW/m2(4±0.4 W/m3), respectively using CoTMPP as catalyst. These results give us new insight into materials like stainless steel mesh and PVDF-graphite as low cost cathode for reducing the costs of MFCs for wastewater treatment applications. [ABSTRACT FROM AUTHOR]

Profiting by the increasing availability of laser sources delivering intensities above 109 W/cm2 with pulse energies in the range of several Joules and pulse widths in the range of nanoseconds, laser shock processing (LSP) is consolidating as an effective technology for the improvement of surface mechanical and corrosion resistance properties of metals. The main advantage of the laser shock processing technique consists on its capability of inducing a relatively deep compression residual stresses field into metallic alloy pieces allowing an improved mechanical behaviour, explicitly, the life improvement of the treated specimens against wear, crack growth and stress corrosion cracking. Although significant work from the experimental side has been contributed to explore the optimum conditions of application of the treatments and to assess their ultimate capability to provide enhanced mechanical behaviour to work-pieces of typical materials, only limited attempts have been developed in the way of full comprehension and predictive assessment of the characteristic physical processes and material transformations with a specific consideration of real material properties. In the present paper, a review on the physical issues dominating the development of LSP processes from a high intensity laser-matter interaction point of view is presented along with the theoretical and computational methods developed by the authors for their predictive assessment and practical results at laboratory scale on the application of the technique to different materials. [ABSTRACT FROM AUTHOR]

The nanocrystalline Mg3CoNi2 alloys have been synthesized from Mg, Co and Ni pure metal powder by using a SPEX 8000 High Energy Milling through wet method with its vial and ball made of stainless steel. A weight ratio of ball to sample was set at 8:1 and the milling times were set at 20 and 30 h. SANS measurements were performed in an instrument SMARTer at BATAN using a distances between 1.5, 4 and 13 m and a wavelength, λ, of 0.39 nm. The SANS investigation results showed that the intensity profiles decrease with q and a power law exponent of about 4. It is suggested that surface Porod scattering dominates. The relative intensity decreases with increased hydrogen concentration, indicating a decline in surface area. Hydrogenation leads to significant changes in the scattering curves mainly due to the 1 Mg2Ni attice expansion and changes of the Mg2Ni-H/Mg2Ni phase boundaries and that of the Mg2Ni or Mg2NiH4 grain boundaries. The samples absorb about 3.3 and 1.9 wt% hydrogen with increasing milling time of 20 and 30 h, respectively. [ABSTRACT FROM AUTHOR]

In the past few years, ultra-high frequency pulse tube cryocoolers are becoming a research hotspot for their portability and compactness in aerospace and aviation applications. For preliminary research, a two-stage pulse tube cryocooler working at 300 Hz driven by a thermoacoustic engine is established to investigate the problems due to ultra high frequency, and several results have been derived in our early reports. In order to study the effect of thermal penetration depth, this paper presents the cooler adopting copper mesh as the regenerator, and comparison with stainless steel mesh is given. In addition, the influence of inertance tube on the lowest possible cooler temperature is also tested. Finally, we discuss the improvement for getting a lower temperature. [ABSTRACT FROM AUTHOR]

The weldability of Kovar and stainless steel alloys by Nd:YAG laser beam is studied through changing of some laser beam parameters. It has been found that there is a suitable interaction of the pulsed laser beam of low power laser pulse with both the two alloys. The change of thermophysical properties with absorbed energy from the laser pulse is discussed in this paper which reports the suitability of both Kovar and stainless steel 304 as the base materials for photonic devices packaging. We used laser weld system (LW4000S from Newport) which employs Nd:YAG laser system with two simultaneous beams output for packaging 980 nm high power laser module. Results of changing both laser spot weld width and penetration depth with changing both the pulse peak power density, pulse energy and pulse duration show that there are good linear relationships between laser pulse energy or peak power density and pulse duration with laser spot weld dimensions( both laser spot weld width and penetration depth). Therefore we concluded that there should be an optimization for both the pulse peak power and pulse duration to give a suitable aspect ratio (laser spot width to penetration depth) for achieving the desired welds with suitable penetration depth and small spot width. This is to reduce the heat affected zone (HAZ) which affects the sensitive optical components. An optimum value of the power density in the order of 105 w/cm2 found to be suitable to induce melting in the welded joints without vaporization. The desired ratio can also be optimized by changing the focus position on the target material as illustrated from our measurements. A theoretical model is developed to simulate the temperature distribution during the laser pulse heating and predict the penetration depth inside the material. Samples have been investigated using SEM with EDS. The metallographic measurements on the weld spot show a suitable weld yield with reasonable weld width to depth ratio. [ABSTRACT FROM AUTHOR]

Binder system is one of the most important criteria for the powder injection molding (PIM) process. Failure in the selection of the binder system will affect on the final properties of the sintered parts. The objectives of this studied is to develop a novel binder system based on the local natural resources and environmental friendly binder system from palm oil derivative which is easily available and cheap in our country of Malaysia. The novel binder that has been developed will be replaced the commercial thermo-plastic binder system or as an alternative binder system. The results show that the physical and mechanical properties of the final sintered parts fulfill the Metal Powder Industries Federation (MPIF) standard 35 for PIM parts. The biocompatibility test using cell osteosarcoma (MG63) and vero fibroblastic also shows that the cell was successfully growth on the sintered stainless steel 316L parts indicate that the novel binder was not toxic. Therefore, the novel binder system based on palm oil derivative that has been developed as a binder system fulfills the important criteria for the binder system in PIM process. [ABSTRACT FROM AUTHOR]

Thermoelectric power (TEP) measurements have been used as an effective method for evaluating the metallurgical state of various alloys. In the steel industry, some fabrication processes promote phase transformation and second phase precipitations which affect the material properties. Assessment of mechanical properties is critical in order to ensure quality of components. This work was conducted in order to evaluate the influence of the aging state of 2205 duplex stainless steel on TEP values. Commercial 2205 duplex steel was isothermally aged at 650 °C 700 °C and 900 °C at different aging times. TEP measurement technique was applied as a non destructive assessment technique to characterize the aging kinetics of the aged 2205 duplex stainless steel, hardness Rockwell (RC) and Charpy impact test were preformed to observe the effect of aging time on the specimens. Metallographic analysis was used to monitor phase transformation and sigma phase precipitation caused by the spinodal decomposition process of ferrite into secondary austenite and sigma phase. Results indicate that that the TEP is sensitive to gradual microstructural changes produced by the aging treatments. [ABSTRACT FROM AUTHOR]

The calculated energy dissipation associated with the pull-back signal amplitude in plate impact experiment is usually larger than that obtained by accounting the contributions of the estimated plastic work at continuum scale and that due to ductile damage. As a possible explanation, it is proposed that the drop in the stress triaxiality, due to the formation of free surfaces as a result of the first appearance of the damage in form of voids, allows the matrix material to exhibit much larger plastic deformation. In order to verify this proposition, a numerical investigation based on the use of cohesive finite elements has been performed. The proposed numerical model has been used to predict the damage development and the rear pressure profile in a flyer plate impact test on 99.99% Cu and 316 L SS under flat top and triangular pressure wave profile. [ABSTRACT FROM AUTHOR]

In this work, the radial combustion in thin circular samples of stoichiometric and over aluminized Fe2O3/Al mixtures is studied. Two confinement materials are tested: stainless steel and PVC. The combustion front profiles are registered by digital video-crono-photography. The radial geometry allows an easy detection of sample heterogeneities, via the circularity distortions of the combustion front profiles. The influence of the Al content in the mixtures and the type of confinement on the combustion propagation dynamics is analyzed. Additionally, an asymmetry parameter of the combustion front profiles is defined and statistically treated via ANOVA. Although the type of confinement contributes more than the mixture composition to the variability of the asymmetry parameter, they both have a weak influence. The main source of variability is the intrinsic variations of the samples, which are due to their heterogeneous character. [ABSTRACT FROM AUTHOR]

A 20 mm long 8 mm diameter cylindrical tin target has been shocked to a pressure just below the β[bold_arrow]γ phase change, using a small, low density PETN charge mounted on the opposite side of a thin stainless steel diaphragm. The density jump and shock velocity were measured radiographically at multiple points as the shock wave moved though the sample and the pressure dropped, using the proton radiography facility at LANL. This provided a quasi-continuous record along the principal Hugoniot from a peak shock velocity of 3.27 km/sec to a minimum of 3.09 km/sec. Edge release effects were removed from the data using simple tomographic reconstruction techniques. The data and analysis are presented. [ABSTRACT FROM AUTHOR]

Fault detection and diagnosis is an important problem in process engineering. Process equipments are subject to malfunctions during operation. Galvanized steel is a value added product, furnishing effective performance by combining the corrosion resistance of zinc with the strength and formability of steel. Fault detection and diagnosis is an important problem in continuous hot dip galvanizing and the increasingly stringent quality requirements in automotive industry has also demanded ongoing efforts in process control to make the process more robust. When faults occur, they change the relationship among these observed variables. This work compares different statistical regression models proposed in the literature for estimating the quality of galvanized steel coils on the basis of short time histories. Data for 26 batches were available. Five variables were selected for monitoring the process: the steel strip velocity, four bath temperatures and bath level. The entire data consisting of 48 galvanized steel coils was divided into sets. The first training data set was 25 conforming coils and the second data set was 23 nonconforming coils. Logistic regression is a modeling tool in which the dependent variable is categorical. In most applications, the dependent variable is binary. The results show that the logistic generalized linear models do provide good estimates of quality coils and can be useful for quality control in manufacturing process. [ABSTRACT FROM AUTHOR]

Nowadays, one of the industrial sectors with greater implication in the technological development of Spain is the related one to the aerospace industry that, in some zones of the country, has gotten to become the industrial motor of the same ones, and to replace sectors that, by tradition and geographical strategy, had come occupying this place. Being located within this sector in height, the increasing application of titanium alloys is verified for the different constructions, that is to say, the use in light alloy rise. Along with the aluminium alloys, titanium alloys are widely used in the aeronautical industry. The good relationship hardness/weight and the high corrosion resistance turn them excellent candidates for high performance machining operations. Production requirements force a greater surface quality of the machined pieces. In this work a preliminary analysis of the evolution of the surface quality in the dry turning in of the Ti-6Al-4V is carried out, looking for a possible correlation with the geometry of the chips obtained in the tests. In order to evaluate the surface quality the arithmetical average roughness, Ra, has been used. [ABSTRACT FROM AUTHOR]

The corrosion behaviour of AA6061 aluminium alloy in tropical seawater was investigated using weight loss measurement and electrochemical polarization technique. The electrochemical measurements showed that the presence of natural honey as corrosion resistant significantly decrease the corrosion current densities (icorr) and corrosion rates. It was observed that the inhibition efficiencies increased with the increasing concentrations of the resistant. Potentiodyanamic curves suggested that natural honey suppressed both cathodic and anodic processes. A good fit to Langmuir adsorption isotherm was obtained between the degree of surface coverage and the concentration of natural honey. It can be concluded that natural honey is an excellent corrosion resistant for aluminium alloy immersed in tropical seawater. [ABSTRACT FROM AUTHOR]

Work is being conducted to develop phased array inspection of stainless steel welded pipes. Ideally this uses waves reflected and mode converted at the inner surface of the pipe, but most commercial phased array controllers do not currently provide for this. Our solution was to use Full Matrix Capture (FMC) and process the data ourselves. This paper explains the FMC principle, describes the signal processing algorithms along with introducing the Almost Total Focusing Method (ATFM) and illustrates how the processed data was presented. The inspections were also modeled using the CEA CIVA software and compared to experimental results. [ABSTRACT FROM AUTHOR]

Magnetically graded materials based on stainless steel have been developed by martensite transformation technique. It is important to investigate the corrosion resistance of magnetically graded materials made by the martensitic transformation technique from austenitic stainless steel. Corrosion resistant evaluation of stainless steels was performed using an electrochemical sensor in which the potential was chosen as the equilibrium potential. Ag/AgCl electrode was used for the electro chemical sensor. The developed sensor based on the Ag/AgCl electrode detected the concentration of chloride ions which were one of the environmental factors related to corrosion phenomena in the corrosion environment for magnetically graded materials. [ABSTRACT FROM AUTHOR]