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•Anode dissolution of the ternary Pb-Ag-Bi alloys of different compositions was studied in KCl-PbCl2 at 823 K.•Dissolution of Pb-Ag-Bi proceeds primarily via two-electron reaction: ...Pb(Pb-Ag-Bi) → Pb2++2e.•Selective lead dissolution is possible in Pb-Ag-Bi (4.8–35.7–59.5) at 0.006 < i < 0.7 A/cm2.•Pb-Ag-Bi (5.1–35.6–59.3) alloy was obtained from the Pb-Ag-Bi (60.0–15.0–25.0) alloy in the laboratory electrolytic cell.
The anode dissolution of ternary Pb-Ag-Bi metallic alloys with different components concentration has been studied in the molten KCl-PbCl2 eutectics. A lead dissolution was found to be the main process in the Pb-Ag-Bi (60.0–15.0–25.0), Pb-Ag-Bi (42.9–21.4–35.7), Pb-Ag-Bi (7.0–34.9–58.1) alloys within the whole interval of studied anode current densities. The Pb-Ag-Bi ((4.8–35.7–59.5) and Pb-Ag-Bi ((2.4–36.6–61.0) alloys at the anode current densities of 2.3 A/cm2 and 0.14 A/cm2 have the limiting diffusion current of lead dissolution. At the anode current densities exceeding the aforesaid values a bismuth dissolution takes place. The number of electrons participating in each electrode reaction is determined for each mechanism of metal electrodissolution. A regime of electrochemical separation of lead alloys is chosen based on the analysis of polarization curves. Metallic lead and Ag-Bi-Pb (5.1 wt%) alloy were obtained in the laboratory electrolytic cell.
Secondary phase particles (SPPs) have attracted extensive attention because of their effects on the properties and performance of alloy materials. In the present study, a novel ultra-low current and ...temperature controlled electrochemical (ULCT) method, which can expose contained SPPs on the alloy surface, has been proposed for the first time. We demonstrated that the exciting new approach is feasible for the high-quality bulk sample preparation of various common alloys including Zircaloy-4 (Zr-4 alloy), GH99 super alloy and 2A12 aluminium alloy. Results show that this ULCT method is a real universal and promising method for the specific sample preparation, which will make SEM-based techniques become invaluable for routine characterization of SPPs in various kinds of alloys.
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•First report of the routine method for bulk sample preparation with SPP exposed.•The optimized current ranges from 0.01 to 0.1A under a temperature below −100 °C.•SPPs in Zr-4 alloy can be effectively exposed and characterized with this method.•This method is also feasible for 2A12 aluminium alloy and GH99 superalloy.•The principle of this method can be attributed to micro anodic dissolution process.
Excess volume data of 32 liquid alloys were reviewed and plotted versus their excess free energies. It is hereby found that all combinations of the signs of EV and EG are possible. The excess volume ...data split into two different curves which are monotonous in EG. For one of these curves the signs of EV and EG are equal and they are opposite for the other.
We improved our previously developed model and found that there is an unspecified sign which can be chosen either + or -, depending on the system. This explains why there are two curves corresponding to the experimental finding. The model relates excess volume, excess free energy and isothermal compressibility with each other whereby the concept of internal pressure is used.
The model can also predict the excess volume as function of the excess free energy, when the correct sign, either + or -, is known and a reasonable assumption is made for the effective isothermal compressibility. In the present work, the latter has been estimated as an average from the isothermal compressibility values over the involved pure elements. Good qualitative and quantitative agreement with the experimental data is obtained for the systems investigated. The model is valid at least for -3RT < EG < +1RT.
•Excess volume data of 32 liquid binary alloys are plotted versus excess free energies.•The data points collapse onto two distinct branches.•A new model has been developed relating excess volume to isothermal compressibility.
This book is a comprehensive source of the fundamentals, process parameters, instrumental components and applications of laser-induced breakdown spectroscopy (LIBS). The effect of multiple pulses on ...material ablation, plasma dynamics and plasma emission is presented. A heuristic plasma modeling allows to simulate complex experimental plasma spectra. These methods and findings form the basis for a variety of applications to perform quantitative multi-element analysis with LIBS. These application potentials of LIBS have really boosted in the last years ranging from bulk analysis of metallic alloys and non-conducting materials, via spatially resolved analysis and depth profiling covering measuring objects in all physical states: gaseous, liquid and solid. Dedicated chapters present LIBS investigations for these tasks with special emphasis on the methodical and instrumental concepts as well as the optimization strategies for a quantitative analysis. Requirements, concepts, design and characteristic features of LIBS instruments are described covering laboratory systems, inspections systems for in-line process control, mobile systems and remote systems. State-of-the-art industrial applications of LIBS systems are presented demonstrating the benefits of inline process control for improved process guiding and quality assurance purposes.
Chip segmentation is the dominant chip formation mechanism during the machining of high-strength metallic alloys which directly affects the machining productivity and the final product’s quality. ...This paper investigates the mechanism of shear band formation and its contact with the cutting tool for different titanium and nickel alloys. First, we reveal that the shear bands are in direct contact with the cutting tool due to rolling on its rake face, although the contact mechanism is different for titanium and nickel alloys. In addition, the effect of the stored energy at the tool-chip interface, which is believed to be the reason for chip segmentation in some studies, is investigated theoretically. We found that the stored energy at the tool-chip interface affects the strain rate temporarily and has minimal impact on the chip segmentation. Moreover, we provide a theoretical prediction of the workpiece material’s displacement, its distribution, and degree of segmentation for the first time without any post-mortem analysis of the produced shear bands. To this end, the rolling process must be taken into account for accurate prediction. We show that the segmented chip’s displacement can be accurately predicted without any fracture criterion since the shear band itself is a type of ductile material failure. It is shown that the shear bands can accommodate large strains (for example, around 45 when cutting Ti-6Al-4V at 60 m min−1 cutting speed) without fracture presumption.
Creep refers to the slow, permanent deformation of materials under external loads, or stresses. It explains the creep strength or resistance to this extension. This book is for experts in the field ...of strength of metals, alloys and ceramics. It explains creep behavior at the atomic or "dislocation defect" level. This book has many illustrations and many references. The figure formats are uniform and consistently labeled for increased readability. This Second Edition updates and improves the previous edition.
Metal corrosion is a major global concern in many economic sectors. The degradation of metal surfaces is responsible for losses in values that account for about 3% of gross domestic product (GDP) ...only in the US. Parts of all corrosion processes described in different environments are present mainly in marine environments. The marine environment is characterized as favoring the corrosion processes of several metallic alloys, damaging structures used in the construction of ships, ports, oil pipelines, and others. Despite chemical corrosion being the most frequently described in these environments, studies show the participation of microorganisms in direct corrosion processes or in the acceleration/influence of the corrosive action, through the formation of complex biofilms. These structures create favorable conditions for microorganisms to degrade metal surfaces, causing damage known as pitting and crevices. Currently, diverse technicians are employed in biocorrosion research, e.g. electronic microscopy, and DNA sequencing. These techniques have clarified the dynamic process of the formation of biofilm structures, allowing understanding of the succession of different species during the evolution of the structure. Improving the understanding of how this interaction between biofilm and metallic surface occurs will enable better evaluation of strategies to avoid or decelerate the degradation of metallic structures in marine environments.
Understanding of mechanical properties of materials and a possibility to predicting them from ab initio calculations have fundamental importance for solid state theory. In this work we establish a ...significant correlation between the product of the macroscopic parameters of localized plastic flow auto-waves in deforming alloys, their length and propagation rate and the product of the microscopic (lattice) parameters of these materials, the spacing between close-packed planes of the lattice and the rate of transverse elastic waves. Thus, these products can be regard as invariants of plastic and elastic deformation processes, respectively. Moreover, the established regularity suggests that the elastic and the plastic processes simultaneously involved in the deformation are closely related. Our work also demonstrates that ab initio simulations can be used for the prediction of parameters of localized plastic flow auto-waves in deforming alloys.
► We determine parameters of localized plastic flow autowaves in metallic alloys. ► Lengths and propagation rates of the autowaves are determined experimentally. ►Ab initio calculations are carried out for material specific microscopic parameters. ► Significant correlation is established between the former and the latter. ► This suggests that the elastic and the plastic processes are closely related.
Al-based complex metallic alloys (CMAs) are crystalline intermetallic phases characterised by very complex crystal lattices, showing intriguing surface properties such as low wetting, low friction ...and hardness which include, for the Al–Cr–Fe system, high corrosion resistance. However, their passivation mechanisms (nm-thick oxide layer formation) still need to be understood in relation with localised corrosion susceptibility. New single phases were therefore characterised by electrochemical Microcell technique. The chromium cations in the oxide proved to play a significant role in stabilising the passive layer at low pH. Corrosion resistance of single- and polycrystalline samples was first compared by means of inductively coupled plasma mass spectrometer (ICPMS) analysis during immersion. Higher dissolution rates have been measured for the low Cr containing (12.5
at%) polycrystals compared to the single crystals. The resistance to localised corrosion attack of the single crystals in an aggressive 0.01
M HCl
+
1
M NaCl solution at pH 2 was high, with an anisotropic behaviour of the anodic breakdown potential related to the grain orientation. The orthorhombic (0
0
1) termination with higher Cr/Al atoms ratio formed a passive layer with increased resistance against pitting. Ageing of the samples and the formation of surface Al oxy-hydroxide appeared to decrease the pitting corrosion resistance.
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