Mechanical Properties Of Deposits Research Articles

Quantitative Nondestructive Evaluation of Cold Spray Manufactured Aluminum Alloy 6061 and Copper Samples

Cold spray (CS) is a solid-state process for depositing thick layers of material via the successive high-velocity impact of powder particles onto a solid surface, which leads to high rates of deformation, interparticle bonding, and coating build-up. Although CS is finding commercial utilization in non-load-bearing repair and coating applications, clear nondestructive characterization procedures are necessary to realize its potential in load-bearing structural applications. In this study, the viability of electrical conductivity and through thickness ultrasound wave velocity measurement methods was studied to serve as a means for nondestructive quantitative measurement for quality control in CS and potentially other additive manufacturing (AM) methods. Eddy current, ultrasound, porosity, hardness, and uniaxial tensile strength tests were conducted on CS deposited layers of aluminum alloy 6061 and copper on aluminum alloy 6061 and commercially pure copper substrates, respectively. CS gas dynamic parameters were intentionally and systematically varied to result in corresponding discrete differences in mechanical properties of deposits. Ultrasound measurements of longitudinal wave velocity and eddy current electrical conductivity measurements showed good correlation with process conditions, microstructural characterization results, and destructive mechanical tests (hardness, tensile). The results of this work show that ultrasound wave velocity and electrical conductivity correlate well with increased particle impact velocity in CS deposited aluminum and copper blocks, which evidently show an incremental decrease in porosity, increase in hardness, and increase in tensile strength. The outlined ultrasound and eddy current nondestructive testing methods present effective means for quantitative assessment of cold spray deposited structures while intact with the substrate.

Preparation of pulse electrodeposited Ni-B/ZrC composite coatings and investigation of their mechanical properties and corrosion resistance

ZrC particles were embedded into NiB metal composite coatings by pulse electrodeposition in a Watt-type bath at 50 °C and 400 rpm with magnetic stirring. SEM, XPS, and AFM were used to characterize the appearance, chemical state, and surface roughness of the coating. The mechanical properties of deposits were measured by Vickers hardness and reciprocating friction, and scratches caused by linear reciprocating friction were analyzed with SEM and EDS in detail. In addition, the corrosion resistance was measured by the electrochemical impedance and polarization. The test results showed that the nanoparticles were uniformly dispersed across the substrate's surface, and the successful incorporation of nano-ZrC significantly changed the property of the nickel‑boron alloy coating. When the ZrC concentration in the bath was 4 g/L, the coating exhibited the best mechanical properties and corrosion resistance, the Vickers microhardness of the Ni-B/ZrC metal composite coating increased from 523 HV (pure NiB) to 1073 HV, the friction coefficient decreased from 0.462 to 0.218 with a linear reciprocating sliding friction of 10 mm at a speed of 50 mm/min for 20 min under a load of 20 N. In 3.5 wt% NaCl solution at 25 °C and pH = 7, the impedance increased significantly, and corrosion potential became less negative (E = −0.316 V vs. SCE).

Microstructure and Properties of Al-6.0Mg-0.3Sc Alloy Deposited by Double-Wire Arc Additive Manufacturing.

Al-6.0Mg-0.3Sc alloy deposits are prepared by means of a double-wire arc additive manufacturing process. The formation, porosity, metallographic structure, type of precipitated phase, and mechanical properties of the deposit are studied. Double-wire arc forming affords precision advantages over single-wire-arc forming, which is evidenced by the increased surface uniformity of the deposit. Compared with the deposit of single-wire-arc formed, the deposit of double-wire arc formed exhibits only fewer and smaller pores, and the lower process heat yields rapid solidification and tiny precipitate sizes. A larger amount of Mg and Mn is observed to be dissolved in the Al matrix of double-wire arc-formed deposit, which increases the alloy strength, and smaller primary Al3Sc phase, which exhibits excellent grain refinement. Furthermore, the presence of a high amount of Sc solid solution in the matrix of double-wire arc-formed deposit strengthens the alloy, and the melting of the rear wire "heat-treats" the substrate formed by the front wire, promotes secondary Al3Sc phase precipitation, and further strengthens the alloy. Compared with the deposit of single-wire-arc formed, the mechanical properties of double-wire arc-formed deposit show an improvement: the tensile strength, yield strength, and elongation of the horizontally oriented specimens are estimated as 363 MPa, 258 MPa, and 26%, respectively. This successful implementation of the cold metal transfer + pulse process to prepare Al-Mg alloy parts can pave the way to their industrial production. The proposed method can find wide utility in the fields of aviation, aerospace, military, and shipbuilding.

Influence of hot isostatic pressing on the properties of 316L stainless steel, Al-Mg-Sc-Zr alloy, titanium and Ti6Al4V cold spray deposits

In this paper an effect of capsule-free hot isostatic pressing (HIP) on the porosity and mechanical properties of different cold spray deposits was experimentally evaluated. The HIP post-treatment significantly decreased (more than 2 times) the porosity of 316L and pure titanium deposits. The densification effect of HIP on the porous Ti6Al4V deposit was significantly less pronounced. Mechanical properties of the deposits after HIP were also improved. In particular, the tensile strength of the stainless steel, pure titanium and Ti6AL4V increased from 30 MPa, 70 MPa and 20 MPa to 211 MPa, 480 MPA and 560 MPa correspondingly. Compressive strength of the Al-Mg-Sc-Zr alloy samples after HIP was also increased ~25%. Improvement of mechanical properties is explained by material diffusion and microstructure changes during HIP cycle.

The Properties of Pulse-Plated Copper Derived from Additive-Bearing, Low-Metal Ion Concentration Electrolytes

In semiconductor devices, copper metallization patterns are created using a combination of photolithography and electroplating. Photolithography, which uses light to transfer geometric patterns from a mask onto a substrate, is a multi-step process that is costly, time-consuming, and entails the use of harmful chemicals. A recent electrodeposition process called Electrochemical nano and micro Fabrication by flow and Chemistry (EnFACE) was developed to enable single-step, direct, mask-less pattern transfers onto metallic substrates. EnFACE offers the possibility of replacing photolithography and avoid the difficulties associated with the process. For typical copper electrolytes, the use of pulsed current and plating additives are known to improve deposit properties such as grain structure, mechanical strength, and throwing power. However, EnFACE uses an acid-free, additive-free, low-conductivity plating electrolyte containing low concentrations of metal salts (0.1 M CuSO4), a composition which significantly differs from the conventional copper plating electrolytes. Since the chemistry of this electrolyte is relatively new, a majority of its properties still needs to be discovered and understood. In this work, we report on the influence of current modulation (i.e., pulsed-current) on the properties of Cu electrodeposits obtained from additive-bearing, low metal salt concentration electrolyte. Copper films were plated from 0.1 M CuSO4 electrolyte containing different concentrations of plating additives (i.e., 0%, 17%, 33%, 50%, 100%, and 200% of the industry recommended concentration) using direct (DC) and pulsed current (PC) modulations. The operating pulse parameters used were θ = 0.25 at a t p of 100ms and the actual plating time was set for a deposit thickness of 25 um. The mechanical properties of deposits were characterised using the tensile test (UTM), while electrical properties were assessed using the four-point probe. Grain characteristics and morphology was investigated using scanning electron microscope (SEM), electron backscattered diffraction (EBSD), and X-ray diffraction (XRD). Results of mechanical tests indicate that the PC-plated films possessed higher yield strength, tensile strength and ductility than its DC-plated counterparts (see Fig.1). Similarly, electrical measurements confirmed that pulse plated films have better conductivity than the DC plated ones. These changes in properties were traced to the changes in microstructure induced by the application of pulsed current modulation during plating. Finally, the use of pulsed current offers the added benefit of reducing the required amount of additives to obtain the desired deposit properties. The optimum additive concentration was 50% of the recommended value when using DC plating; while it was only 33% in PC plating. Figure 1

Direct Observation of Asphaltene Nanoparticles on Model Mineral Substrates.

The propensity for adherence to solid surfaces of asphaltenes, a complex solubility class of heteropolycyclic aromatic compounds from the heavy fraction of crude oil, has long been the root cause of scale deposition and remains an intractable problem in the petroleum industry. Although the adhesion is essential to understanding the process of asphaltene deposition, the relationship between the conformation of asphaltene molecules on mineral substrates and its impact on adhesion and mechanical properties of the deposits is not completely understood. To rationalize the primary processes in the process of organic scale deposition, here we use atomic force microscopy (AFM) to visualize the morphology of petroleum asphaltenes deposited on model mineral substrates. High imaging contrast was achieved by the differential adhesion of the tip between asphaltenes and the mineral substrate. While asphaltenes form smooth continuous films on all substrates at higher concentrations, they deposit as individual nanoparticles at lower concentrations. The size, shape, and spatial distribution of the nanoaggregates are strongly affected by the nature of the substrate; while uniformly distributed spherical particles are formed on highly polar and hydrophilic substrates (mica), irregular islands and thicker patches are observed with substrates of lower polarity (silica and calcite). Asphaltene nanoparticles flatten when adsorbed on highly oriented pyrolytic graphite due to π-π interactions with the polycyclic core. Force-distance profiles provide direct evidence of the conformational changes of asphaltene molecules on hydrophilic/hydrophobic substrates that result in dramatic changes in adhesion and mechanical properties of asphaltene deposits. Such an understanding of the nature of adhesion and mechanical properties tuned by surface properties, on the level of asphaltene nanoaggregates, would contribute to the design of efficient asphaltene inhibitors for preventing asphaltene fouling on targeted surfaces. Unlike flat surfaces, the AFM phase contrast images of defected calcite surfaces show that asphaltenes form continuous deposits to fill the recesses, and this process could trigger the onset for asphaltene deposition.

The effect of pulse electroplating on Zn–Ni alloy and Zn–Ni–Al2O3 composite coatings

Zn–Ni alloy and Zn–Ni–Al2O3 composite coatings were electrodeposited on mild steel substrate by direct and pulse current in sulphate bath. The effect of pulse electroplating on Ni content, phase structure, microhardness, surface morphology and corrosion resistance of coatings were investigated. Applied pulsed current increased the Ni content for both Zn–Ni alloy and Zn–Ni–Al2O3 composite coatings, which also increased the microhardness of the coatings. XRD results showed that the phase structure of all direct current (DC) and pulsed electroplated coatings was single Ni5Zn21-γ phase. Surface of coatings was smoother and more uniform with smaller nodules’ size for coatings deposited by pulse current. Pulse frequency did not have significant effect on the chemical and mechanical properties of deposits. Corrosion resistance of pulse plated Zn–Ni alloy coatings were improved significantly compared to the DC electroplated coatings. However, this effect was less pronounced for Zn–Ni–Al2O3 composite coatings.

Influence of anionic stabilization of alumina particles in 2-propanol medium on the electrophoretic deposition and mechanical properties of deposits

Abstract The ceramic dispersions were prepared using 0.85, 1.70, 4.25, 12.75 or 21.25 wt.% of monochloroacetic, dichloroacetic or trichoroacetic acid, 15 wt.% alumina and 2-propanol. The mechanism of anionic stabilization in 2-propanolic media was described. Alumina green bodies were prepared from the stable dispersion via electrophoretic deposition (EPD). It was found that increasing dispersion conductivity significantly influenced the EPD yields. The most effective electrophoretic depositions were performed from dispersions with conductivity in range 4.0–5.3 × 10 −4 S m −1 . Deposits with the highest green density were prepared from the dispersion stabilized by trichloroacetic acid. This behavior was explained by low voltage drop during deposition. The surface roughness was high at low dispersion conductivity and with increasing acid concentration in dispersion the surface of deposits was smoother. The mechanism of particle arrangement in deposit was discussed. Influence of stabilizer amount in the dispersion on the hardness and fracture toughness was described.

The Improvement of the Physical and Mechanical Properties of Steel Deposits Obtained by Thermal Spraying in Electric Arc

Steel depositsobtained by thermal spray arc have physical-chemical and mechanical properties dependent on operational parameters of the spraying process. Thus, the electric current intensity, the spray distance, the velocity, respectively the driving gas pressure are the parameters that influence the mechanical properties of the steel deposits obtained by thermal spraying. The interaction between particles- gas drive seen in the classic arc spray has the effect the lowering of particles temperature and implicitly of the physical and mechanical properties of the deposit. Using a new device, combined, in which over the thermal field, created by the electric arc, would overlap a second thermal field, created by a gaseous fuel burning, would determine the maintaining of high temperature of the particles and implicitly changes of the physical, chemical and mechanical properties of the deposit. Such a combined spraying device would be called device for spraying in electric arc-thermally activated. The paper aims to present a comparative study of the physic chemical and mechanical properties of steel deposits obtained with two spraying processes: the classical process and the combined spraying process - in electric arc thermally activated.Investigations carried out on the structure of deposits by electron microscopy SEM, XRD analysis and image analysis performed at zone level Layer-Substrate as well the deposits adherence assessment in accordance with EN 582-allows the highlighting properties, the arguing of differences between the properties of the deposits made by the two methods as well as the establishing advantages and disadvantages using those processes.

Effects of gravity on the electrodeposition and characterization of nickel foils

The effects of gravity on nickel electrodeposition, the morphology and mechanical properties of deposits were studied in a super gravity field. Predictions in a microgravity field were also presented based on the obtained experimental tendency. Linear sweep voltammetry reveals that the nickel electrodeposition process is enhanced by increasing the gravity coefficient (G). The limiting current density changes from 10.2 to 293.0 mA·cm−2 with the increase of the G value from 10−4 to 354. The morphology of deposits was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The images show that the morphology deposited in the super gravity field has finer grain sizes and denser and smoother surfaces. The roughness reduces from 48.3 to 4.9 nm with the increase of the G value from 10−4 to 354. Meanwhile, mechanical tests indicate that the mechanical properties of nickel foils are greatly improved due to introducing a super gravity field during electrodeposition.

Influence of additives and plating parameters on morphology and mechanical properties of copper coatings obtained by pulse electrodeposition

In this study, the influence of additives (Cl−, thiourea and gelatine) and pulse plating parameters on the structure and properties of copper coatings obtained through an acid copper plating bath was studied. In order to determine the properties of deposited layers, a microhardness tester was used for microhardness measurement, X-ray diffraction for microstructural analysis, and a scanning electron microscope equipped with an electron backscatter diffraction module for determining morphology and obtaining crystallographic information. In addition, transmission electron microscopy was used to study the presence of twin boundaries in the copper coatings. The experiment results showed that pulse plating and addition agents mutually interfere with each other, causing changes in the microstructure that lead to changes in the mechanical properties of the copper deposits. By the appropriate combination of additives with pulse plating parameters it was possible to synergistically improve the quality and mechanical properties of the deposits.

Some Characteristics of AZ31/AZ91 Dissimilar Magnesium Alloy Deposit by Friction Surfacing

Monolayer friction surfacing was performed using a numerical controlled full automatic friction welding machine for AZ31 magnesium alloy plate used for substrate and AZ91 magnesium alloy casting bar used for consumable rod. Effect of the surfacing conditions on structures and mechanical properties of deposit were investigated. It was clearly observed that the circular pattern appeared on the surface of deposit by the rotation of coating rod. Microstructures of deposit showed finer structure than that of both base metals, and the cast structure was disappeared. Hardness of the deposit showed higher value than that of the substrate. Wear resistance of the deposit was improved in comparison with the substrate.

Chromium electroplating from sulfate-oxalate solutions containing nanoparticles of alumina and silicon carbide

The effect of the introduction of Al2O3 and SiC particles into the base chrome-plating sulfate-oxalate Cr (III) bath on the electrochemical characteristics of chromium deposition, as well as the structure and mechanical properties of deposits, is studied. It is shown that Al2O3 particles are incorporated only into the surface film and are not detected in the bulk of the coating. Particles SiC are incorporated into both the surface film and the deposit. Introducing the particles into the bath makes the cathode polarization at a fixed current density, as well as the current efficiency and the bath throwing power, increase.

Aspects of the Mechanical Properties of Electrodeposits

AbstractThe strengths and ductility of electrochemically deposited metals generally are different from those of the corresponding ones produced by other means. The difference is due to the growth mechanism of the deposits, that they can contain substances which are unstable at elevated temperature and the presence of various crystal defects. The effects on the mechanical properties of electrodeposits of dislocations, twins, voids, codeposited foreign materials, surface crevices, subgrain and grain boundaries, internal stresses and textures are discussed. The ways polarization, current form, solution temperature and agitation affect the mechanical properties of deposits are reviewed. A discussion of the relationships between hardness, the tensile and the fatigue properties is also included. Annealing effects and those of special structures on the properties are also considered.

Kinetics of Electroless Copper Plating and Mechanical Properties of Deposits

Electroless copper films were prepared from an EDTA bath in which pH was adjusted with three kinds of alkalis (, , and ). Mechanical properties of the deposits and the kinetics of electroless copper plating were investigated to clarify their mutual relationship. The use of , among the alkalis tested, gave the best result for the mechanical properties. The electrochemical analysis of the electroless copper deposition based on the mixed potential theory indicates that there is an interaction between the partial anodic and cathodic reactions, which is induced by the adsorption of methylene glycol anion. The polarization technique using a quartz crystal microbalance electrode and the AC impedance method disclose that an improvement of the mechanical properties of copper films is achieved when such an interaction is eliminated by preventing the adsorption of methylene glycol anion through utilizing and surfactant such as polyethylene glycol as well as elevating the bath temperature.

In-Situ Measurements of Wave-Induced Pore Pressure for Predicting Properties of Seabed Deposits

ABSTRACTThis paper proposes a new method for predicting physical and mechanical properties of deposits near the surface of seabeds by means of in-situ measurements of wave-induced pore pressure. Fi...

PREDICTION OF PROPERTIES OF MARINE SAND BY IN-SITU MEASUREMENT OF WAVE INDUCE PORE PRESSURE

The purpose of this paper is to predict the physical and mechanical properties of deposits near the surface of the seabed by in-situ measurements of the wave-induced pore pressure. First, the wave-induced pressure both at the surface of the seabed and inside the seabed are examined by frequency analysis, to clarify the propagation characteristics of pressure in the seabed. Secondly, a theoretical equation which gives the relationship between pore pressure fluctuation and wave pressure fluctuation is proposed. Thirdly, the porosity of the seabed is predicted by the propagating characteristics of the pore pressure within the seabed based on the results of both the model tests by wave tank and the field measurements of the wave-induced pore pressure. Finally, by fitting the theoretical equation to the spectral ratio of the in-situ measured pore pressure fluctuation to wave pressure fluctuation, the bulk modulus of the seabed and the degree of saturation are predicted.

Decorative Electrodeposited Metallic Coatings

AbstractElectrodeposition of metallic coatings for decorative purposes is such an extensive topic that it is intended to review in detail only the most important metals. Some indication of types of plating solutions and general formulations is given, but voluminous patent literature exists on this subject. The physical and mechanical properties of deposits will be considered only in so far as they are relevant to the use of coatings for decorative purposes. Though the coatings to be discussed are essentially employed to provide an attractive appearance, in most instances some degree of protection of the substrate is also inevitably implied. Decorative coatings would be of little value if they either deteriorated rapidly themselves or allowed corrosion of the substrate to occur. The severity of the environment to which a coating is subjected varies considerably. For example, motor-car components may be exposed for almost their entire life in an industrial atmosphere containing a high concentration of sulph...