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Atomic Diffusion Additive Manufacturing (ADAM) is a recent metal sintering process based on known composite printing technology. ADAM can be classified as indirect additive production using fibre of metal powder bound in a plastic matrix. The plastic binder allows the metal powder to remain in place when is printing. Thus, a "green part" is printed and then the plastic binder is removed by the post-washing and sintering process. The aim of this work is providing a brief description of the ADAM process patented by Markforged. Furthermore, the main task was to compare the technology with other sintering technology, namely SLM technology. It works on the basis of selective bonding of metal powder using the thermal energy of the laser beam. Parameters, such as dimensional and shape accuracy, roughness of printed surfaces or tensile strength of printed samples were examined and compared. Dimensional accuracy of the ADAM process was evaluated using ISO IT grades - determined on the basis of the reference standard. The observed accuracy of the sintering process was comparable to traditional production processes.

A considerable attention is paid to the production and monitoring of the properties of metallic cellular structures and the properties of aluminium foams, respectivly. Foam structures can be manufactured in three basic ways (by blowing the external gas into the melt, by melt gasification due to the thermal decomposition of the foaming agent, by the melting of the foamable preform which contains foaming agent particles). The paper addresses to our publication [18] and furthermore focuses on the investigation of mechanical properties of two types of foamed AlSi12 aluminium alloy samples. Samples (150x25x10 mm) were produced by powder metallurgy using a foaming agent TiH2. The characteristics features of the produced foam structures (relative density, porosity, volume fraction of solids, Young's modulus of elasticity) were studied on AlSi12 alloy samples. In addition, the porosity of samples and continuity of their air cells were monitored usign the scanning electron microscope.

Lighting and noise belong to important environmental factors that have an influence on human psyche, concentration, labour protection, sleep quality and so on. This paper is focused on study of light transmission and noise attenuation properties of light active glass materials, which are applied as window and door panels in residential buildings. The light transmission through tested materials was evaluated by means of the transmission coefficient from the illuminance ratio method. The material ability to dampen noise was determined based on the sound pressure level attenuation during sound propagation through the light active glass materials. Different factors, which have an influence on the propagation of light and noise through the investigated glass materials, were evaluated in this work. Finally, the effect of the light transmission through the tested light active glass materials on the daylight quality in a living room was mathematically simulated using Wdls 5.0 software.

The presented article deals with the determination of selected mechanical properties of additive ma-terials used for 3D printing (PETG, PLA, ABS, ABS +, PLA ESD, ASA, PC / ABS). Due to the fact that 3D printing has exploded over recent years and additive manufacturing has become popular in some industries, the quality of input materials and their mechanical properties is extremely im-portant. We used 3D printer Original Prusa MK3 to prepare samples for testing. Individual samples printed from all above mentioned materials were analyzed using selected mechanical tests (static tensile test, hardness tests). In the static tensile test, selected parameters (tensile strength limit, ten-sile modulus, elongation) were determined for all additive samples, which were statistically pro-cessed. The parameters for two methods of measuring hardness were also statistically evaluated, namely Shore and ball indentation. All tested additive materials were compared with the aim of ob-taining the final ranking (point evaluation of tested materials with quantification of price costs). The best properties after the performed tests were achieved by the additive material PLA Filament Plasty Mladeč.

The article deals with new types of coatings and their mechanical properties. CTRN and CRONAL are newly developed coatings intended for active parts of forming tools. Their behavior and mechanical properties are still under investigation. Coatings are used for functional components in various areas of industries, their de-velopment is constantly in process. The aim of the study and the experimental solution provides a compari-son of the mechanical properties of the new coatings with the well-known coatings DLC, TiN and TiSiN. The aim of the work was to perform an analysis of CTRN and CRONAL coatings and compare their me-chanical properties with other coatings. We chose the methods of nanoindentation, hardness measurement, scratch test and layer roughness. The results will allow easy determination of the proper coating for a suitable material. The results present the specific functionality of the individual coatings.

The constantly developing aerospace industry places demands on increasing productivity and produc-tion efficiency. At present, new construction materials are being produced that have better physical and mechanical properties than conventional materials. In addition to new materials, new cutting materials and new machining technologies are being developed. The combination of suitable machin-ing technology, material and tool will achieve excellent product surface quality, long tool life and thus production efficiency. Due to its mechanical and physical properties, technical ceramics can be used in the machining of difficult-to-machine materials, in which there is mechanical stress on blows, impacts, abrasions and other damage. Thanks to these properties, ceramics as a material is very suit-able for the production of machine tools. The presented article deals with the applicability of ceramic milling cutters in high-speed machining of nickel alloy, which is used mainly in the aerospace indus-try. The evaluation of the experiment took place by means of DoE - analysis of cutting forces, the result of which is the creation of the dependence of cutting forces on cutting conditions. Based on the data obtained, it is possible to continue to further intensify the cutting conditions in the area of high-speed machining.

Incomplete bainitic transformation during austempering treatment is mainly caused by the supersatu-ration of austenite with carbon. Such supersaturated austenite becomes more stable and further stabi-lization is led by silicon alloying. Stable austenite does not transform and remains in the structure as so-called residual austenite. Therefore, carbides, which are desirable in a conventional bainitic struc-ture, cannot be formed and carbide free bainite is formed. The positive effect of silicon and carbon on austenite stabilization in CFB structures has already been demonstrated and described. However, another element that is crucial in the incomplete bainitic transformation is chromium. The influence of chromium on the development of microstructure in unconventional AHS steels during austemper-ing is discussed in the experiment in this paper.

This study is focused on testing the ballistic resistance of composite materials to define their limit thicknesses according to the US STANDARD NIJ 0101.06, level III. The materials Twaron CT 747, Twaron CT 747 TH110 and Endumax Shield XF33, which are widely used in the manufacture of the ballistic protection systems, were tested. A method known as the Taylor Anvil Test (TAT) was used to verify their ballistic resistance. The missile 7.62 mm M80 was used to test the ballistic resistance of these materials. Within the experimental part, the deformation processes of composite materials were examined after impact by this missile. The value of the traumatic effect according to the US STANDARD NIJ 0101.06 was also measured. The results of the experiment provide an idea of the ballistic resistance of selected materials. Based on the results, TAT proved to be the perspective measurement method for further development and optimalization of the multilayer composite armor.

This paper investigates the rubber wood honeycomb core by manipulating its cell wall thickness. Rubber wood honeycomb core was fabricated with cell walls range from 1 mm to 3 mm. The impacts of the cell geometrical parameters on the flexural and out-of-plane compression performance are studied. In the case of solid rubber wood without facesheet, the density is much higher than those rubber wood honeycomb composites. The failure can be disastrous without facesheet under bending. Rubber wood honeycomb sandwiches are able to offer the similar specific flexural strength with lower density. With increasing wall thickness from 1 mm to 3 mm, the specific flexural strength increased by 12.32 %. Meanwhile, specific compressive strength improved by 11 % from 1 mm to 2 mm. However, its specific strength dropped by 3.55 % when the wall thickness at 3 mm. Minimum improvement in the compressive strength per density has caused the decrement.

The effects of punch radius, deep-drawing speed and amplitude on the friction coefficient were studied on an improved drawing-bulging friction coefficient testing device on basis of ultrasonic vibration. A contact friction model based on the tribology theory of adhesion and plowing was constructed and used to explain the friction reduction phenomenon of applied out-of-plane normal vibration. The results show that the friction coefficient decreases with the increase of ultrasonic vibration amplitude. At the same deep-drawing height, the friction coefficient decreasing rates at amplitude of 7.8um and 10.1 um on the deep-drawing speed of 0.1 mm/s and 10 mm/s, were 6.7% and 18.8%, respectively. the friction coefficients at the punch radii R0.3 and R1.5 declined from 0.18 to 0.13 and from 0.12 to 0.11. The friction coefficients of thin specimens were larger than thick specimens whether ultrasonic vibration was applied or not. The average friction coefficient from theoretical modeling (μ_v) was smaller than the friction coefficient without ultrasonic vibration (μ_0), and the relative friction coefficient ratio declined with the rise of amplitude and was inversely proportional to time.

In terms of physical and chemical properties, titanium and its alloys are among the most important construction materials today. The Ti6Al4V alloy can be classified among high-strength materials with good plasticity, corrosion resistance and other valuable properties. When performing operations associated with long-term heating of workpieces and parts made of titanium alloys in an air atmosphere, a TiO2 layer is formed on the surface of the product. Ti6Al4V alloy, also known as Ti64, in terms of microstructure is a two-phase alloy formed by α+β solid solutions, which has excellent corrosion resistance and biocompatibility. This alloy is also suitable for jet engines, gas turbines and many aircraft components, as well as in biomedicine. Heat treatment can further improve its technical properties, reduces stress, improves machinability, fracture toughness. The surface of alloys can also be thermally stressed when micro and nano layers of material are applied, which serve to extend the life of products made of this alloy. The presented article analyzes the effect of heat treatment at temperatures of 550 °C and 600 °C and corrosion load with salt fog in the range of 168 to 720 hours on the microstructure and microhardness of the Ti6Al4V alloy.

Titanium aluminides were prepared using self-propagating high-temperature synthesis (SHS) from powder aluminium and compact Ti-6Al-4V alloy at 800 °C. The resulting material was subsequently annealed at the same temperature for 3 hours. The coating was successfully bonded to the matrix using SHS while forming intermetallic phases of cubic TiAl3 in areas of powdered aluminium. The resulting coating was approximately 14 μm thick. Material annealing resulted in further reactions between the TiAl3 coating and Ti-6Al-4V matrix, forming a thin layer of γ-TiAl. Using SEM, the different phase composition of annealed and unannealed material was clearly visible, however, clear determination of emerging phases was very difficult due to the small thickness of the intermetallic coating. Eventually, phases were determined by a combination of cross-section μ-XRD and various EDS analyses.

The aim of the article is to analyze the friction welding process of steel pistons, due to the small amount of scientific literature on this subject. First, it is necessary to present the design fea-tures of steel pistons and their advantages and disadvantages. Then analyze the types of friction weld-ing processes used in the production of pistons of internal combustion engines with the analysis of their differences. Present two basic methods of welding in the production of steel pistons, i.e. friction butt welding and low pressure friction welding. Finally, a proper analysis of the friction welding pro-cesses of steel pistons of internal combustion engines can be presented. At the end, the conclusions of the analysis are presented and proposals for improving the process are made.

The publication focuses on the testing of the tensile strength of samples produced by Fused Filament Fabrication additive manufacturing technology. Three materials rPLA, rPETG and rPET were tested. These materials are recycled PLA (Polylactic Acid), PETG (Polyethylene Terephthalate Glucol) and PET (Polyethylene Terephthalate). These materials were used to create samples for tensile testing according to ASTM D638. In addition to testing the materials, the methodology was also tested using sets of specimens printed with no outer perimeters, one outer perimeter and two outer perimeters. Tensile diagrams were created from the measured data. Statistical processing and comparison of the measured data is performed in the publication. In the discussion, a comparison of the mechanical properties of recycled materials for 3D printing versus virgin materials for 3D printing by Fused Filament Fabrication technology is made.

Variable Polarity Plasma Arc-Metal Inert Gas (VPPA-MIG) welding process is a new hybrid welding process with broad application prospects for aluminum alloy structure in the fields of aerospace manufacturing, transportation and others. The heat source of the hybrid welding process is composed of VPPA heat source and MIG heat source. When the total input energy of VPPA-MIG hybrid heat source is constant, the different energy ratio of VPPA arc and MIG arc affects not only the forming effect of hybrid weld, but also the stress distribution of hybrid welding joint. Hole-drilling method was used to analyze the influence of the ratio of VPPA and MIG arc energy on the distribution of welding residual stress in the process of 10 mm 7A52 aluminum alloy VPPA-MIG hybrid welding. The results show that the peak magnitude of hybrid welding residual stress increases with the increase of the ratio of VPPA arc energy. Considering the appearance of weld forming, VPPA-MIG hybrid welding parameters of 7A52 aluminum alloy are optimized on the basis of the distribution characteristic of residual stress. When the ratio of VPPA arc energy is selected between 35% and 40%, the peak magnitude of transverse residual stress is (in the direction vertical to the weld) no more than 92.0 MPa, and the peak magnitude of longitudinal residual stress(in the direction parallel to the weld) is no more than 234.3 MPa. It shows that the VPPA-MIG hybrid welding with optimized parameters can not only produce weld joint with satisfied macroscopic appearance, but also avoid high peak magnitude of residual stress.

The study is focused on the dynamic response of the head and thoracic area of an anthropomorphic test device (ATD) during low-impact collisions with a tram. Two collision scenarios were analyzed: the frontal impact (a chest as a primary contact area) and the side impact (a thigh as a primary contact area). The measurements used a pedestrian dummy (Hybrid III 50th percentile male dummy, Jasti Co., ltd., Tokyo, Japan) and a unique pendulum impact testing machine (impactor) of own design. The crash tests were conducted at various impact intensities (velocities) into the chest and left thigh of the dummy. The primary outcome variable was a resultant magnitude of acceleration measured in the area of thoracic vertebra Th5 and on the vertex of the head. The differences between both areas of interest were analyzed as well. The results provide the analysis of the dynamic behavior of the head and chest of the dummy at low impacts, the validation of the impactor for crash-test analyses, and a possible way to verify the use of the dummy in similar experimental settings.

Natural fibre-reinforced polymer (NFRP) composites can be environmentally friendly and cost-effective alter-natives to synthetic fibre-reinforced composites. Major industries have expressed significant interest in the advancement of new natural fibre-reinforced composite materials. However, these materials perform poorly on their own and require further analysis since accessible information is lacking in the literature. This paper presents the results of previously reported works on natural fibre reinforced polymer composites, with strong attention to the types of fibres employed, the polymers used in the matrix, the treatment of fibres as well as the test parameters. The best proportion of composites is consequently selected. Composite materials are tested using a CNC router machine. Pinewood dust is combined with vinyl ester resin. A hand layup tech-nique is used to prepare the samples. The availability of relevant pinewood dust and the volume of pine wood dust to be used are first determined to continue with the experiment. According to the findings, the impact of machining performance is successfully evaluated by employing the tensile strength test, Charpy impact test, flexural strength test and surface roughness measurement. The findings are derived from the microscopic assessment of the surface roughness of pinewood dust (PWD) fibre reinforced vinyl ester resin.

Today's demands directly encourage to utilize the light alloy materials in industrial production. In the automotive industry, there is an increasing tendency to reduce the total weight of the car and thus also the weight of the individual car-body parts. A correct description of the material deformation behaviour with respect to the different stress states is very necessary for the own possibility to use these materials in the production. This paper describes a measurement of the mechanical properties and deformation behaviour of aluminium alloy Amag 6000 under the plane strain conditions. Thus these properties are monitored and evaluated by means of the plain strain tensile test. In this case, the plane strain is achieved by the shape concept of the testing specimen, which is loaded by the uniaxial tensile stress state using a standard testing device. The determined mechanical properties and the resulting stress-strain curves of the material under the plain stress state can be further used at defining material models for a more accurate description of the material deformation process during the sheet metal forming process.

This paper describes experimental measurements of travel rollers on a polyurethane thread. This exper-iment took place at the CTU Faculty of Mechanical Engineering in the laboratory of the Department of Design and Machine Parts. The experiment was performed within the project of a lightweight type of sampler, designed by a team of collaborators from our institute for OK Servis BioPro, s.r.o. For the new-ly designed type of sampler, it was necessary to determine the operation of a newly designed grain sampler. The load of the rollers is different in each environment. This paper presents the average values from the measurement, including its evaluation. Moreover, the paper compares different temperatures that can be achieved in the practice. Negative temperature values were not performed, as this meas-urement would be expensive and inefficient.

Selective laser melting (SLM) technology has strict demand to its powder materials which is needed to be spread evenly and conducted laser sintering layer by layer. Therefore, the uniformity and flatness of powder bed are the basic conditions for processing. Ball milling is an important composite powder preparation process of SLM. Three kinds of ball milling processes, dry ball milling, wet ball milling and hollow milling with various parameters are adopted to prepare TC4 / TiB2 composite powder. It is concluded that a balling time 8 h at a speed of 230 rpm without milling ball is proved the optimal working condition to make the composite powder maintain good spherical shape and ensure the mixing uniformity. The mechanism of three kinds of powder mixing effects is revealed by analyzing the dynamic relationship and hardness of the milling ball, TC4 and TiB2 particle. This work provides an important reference for the preparation of high quality TC4 / TiB2 composite powder for SLM.

This study focuses on performing the analysis of manipulator operations on the machining line of precision mechanical products using the Human-Machine correlation analysis tool through images collected from the camera, wasteful operations incurred in machining according to Lean Six Sigma (LSS) standards to control fluctuations in the machining line, improving the overall productivity of the line (OEE). Specifically, contributing to improving productivity, quality, and competitiveness of the company in the market, create a good product image for consumers. This paper proposes a 7-step quality control (QC) cycle improvement model, called 10 step QC cycle. In step 5, use Man - Machine correlation analysis tool from video images to identify wasteful activities. In step 6, we propose a Direct Numerical Control (DNC) model to call the machining program for MC machines using a barcode system and a computer vision model for human identification at each processing line according to a controlled fixed layout. The right people have been trained enough to operate the line; the specific result is eliminating the occurrence of accidents in processing from 7 cases to none. A model of a product dimensioning system implemented for fully automated product quality control combined with redesigned machining jig with a vapor sensor system eliminating the reliance on human manipulation Specifically, the result from this improvement activity is the increase in productivity from 115 products per 8 hours to 155 products per 8 hours and the handling time has decreased from 1.3 hours per day to 0.36 hours per day (reduce 0.94 hours per day). The Partial Least Squares Structural Equation Modeling (PLS-SEM) is used to analyze the results of the survey of employees' opinions about the usefulness, convenience, and technical factors after the operation. The results from improvement activities show that user loyalty is highly appreciated in terms of usefulness and convenience. However, in terms of technical factors, it is still necessary to improve the quality of the information network system, the barcode scanning system and the quality of barcodes in the oil environment

The application of different structural materials to manufacture basic parts of drying units of various types was analyzed. It has been established that surface erosion of materials resulting from solid par-ticles' impact is a serious problem for many industrial equipment types using multiphase flow. It is shown that the value of the erosion rate depends on the local particle impact velocity and the impact angle and can be calculated using the software Ansys Fluent 18. The basic principles and criteria for selecting materials for the manufacture of chemical equipment were substantiated. The behavior of steel and polymer material for shelf contact of the convective dryer in the conditions of erosion wear was modeled, the comparative characteristic was made, further research was planned.

The changes in the material properties of water turbine blades are characterized an undesirable process, which could lead to the end of usable life or to the emergency conditions of this turbine. For this reason, it is important to determine of any material quality changes and continuously monitor them. Considering that, these essential parameters are showing the ability of material to resist the operational stress. It is necessary to choose rapid methods of the material testing which are without preparation of the samples (it is inadmissible to the functional blades) able to immediately monitor the state of the materials by non-destructive methods. Due to mechanical stress and operational wear, the losses and damage occur in the water turbine blades, as the result, it leads to the deformation changes. This article is focused on the methodology of determination mechanical properties of corrosion-resistant steel, which is used on a large scale for the production of hydraulic elements and especially blades of water turbines.

This article seeks to compare roughness characteristics of surfaces created through unconventional machining technologies, specifically utilizing plasma and laser. Cuts of different thickness of material were taken for this purpose. Furthermore, the article presents an evaluation of surfaces obtained from an impression material SILOFLEX®, followed by the determination of similarities between these impressions and original surfaces. In this work, we mainly aimed to statistically find and determine the differences inbetween the evaluation of surfaces in concert with ISO 4287, ISO 4288, and ISO 25 178. Next, investigation analysis of the machined and replicated surfaces was done utilizing the contactless profilometer and the follow-up statistical evaluation of measured data from compared surface groups.

The issue of accident analysis in relation to railway vehicles of urban mass transportation is highly accentuated at the moment. In terms of designing the frontal area of trams, adequate attention should be paid to the optimal front end design in order to reduce the risk of pedestrian injury. The properly used shape and materials can minimize the consequences of the pedestrian’s contact with the vehicle, or the eventual dragging of the pedestrian under the vehicle. For the front end to be tested and optimized, it is necessary to develop and validate a pedestrian model for performing calculations even in the design preparation stage. From a historical perspective, impact tests and pedestrian protection were not paid significant attention. There should also be a methodology for data collection and evaluation across the public transit company. The data collected within the Czech Republic is inconsistent and hard to analyze. At the beginning of our research, we addressed the question of which dummy configuration with respect to the tram is most appropriate for our crash tests.

The continuous development of construction due to the great needs of society and industry, the need to build newer and more durable buildings have meant that scientists all the time look for new opportunities to improve the quality of materials used in this field. Above all, concrete, as material commonly used in construction, has been the subject of research for many years in order to improve the properties. Already in antiquity there were the first attempts to modify the building material with fibers. Initially, they were organic fibers. However, the first patent dates from 1874, when A. Bernard patented the idea of strengthening concrete with steel filings [1]. Then, attempts were made to strengthen the concrete with long steel fibers, which was done by H. Alfsen in 1918. Further researches led N. Zitkiewic to test the strength and impact toughness of concrete with the use of pieces of mild steel wire [2]. Steel fibers in concrete were used for the first time by Romuladi and Baston in 1963. In the paper a comparative analysis of selected mechanical properties for concrete and fiber-reinforced concrete, e.g. compressive strength and Young's modulus, was presented. It was checked how the value of Young's modulus and the compressive strength of concrete change depending on the content of steel fibers. Three types of samples were tested: 1 - concrete, 2 – fiber-reinforced concrete containing 0.25% of steel fibers, 3 – fiber-reinforced concrete containing 0.50% of steel fibers. As the analysis has shown, the greater number of steel fibers is not directly proportional to the increase in its compressive strength or the value of Young's modulus.

The present work describes the influence of Al content on the CoCrFeNiAl high-entropy alloys pre-pared by the powder metallurgy technique. The preparation procedure consisted of mechanical alloy-ing and subsequent spark plasma sintering. The content of Al varied from 10 – 30 at.% which affected the microstructure and mechanical properties. Using scanning electron microscope (SEM) and X-ray diffraction analysis (XRD) was found the microstructure becomes more refined with increasing con-tent of Al accompanied by the annihilation of the ductile FCC solid solution (Cr0.25Fe0.25Co0.25Ni0.25) phase and growth of the brittle and hard BCC solid solution phase (α-Fe) and formation of Al(Co0.5Ni0.5) phases, improving the mechanical properties. The best combination of the porosity, hardness HV 30, and ultimate compressive strength (UCS) was achieved for the studied high-entropy alloy when it contained 20 at. % Al.

Superalloys are a group of alloys developed for use during long-term heat exposure above 650 °C. Properties and applications of superalloys are described in the present work. The work includes statis-tics about superalloys demand, market value and the current price. Division of superalloys according to basic element is mentioned. Nickel-based superalloys are further divided into two groups accord-ing to their use. Afterwards, the paper is focused mainly on nickel-based superalloys. Examples of nickel-based superalloys are listed in the work. Recycling possibilities of nickel-based superalloys are stated and analysed. General scheme of processing nickel-based superalloy scrap with regard to the content of rhenium is proposed and shortly discussed. The best-known companies dealing with sup-eralloy scrap recycling are mentioned further.

The article is devoted to the influence of mold filling parameters by the HPDC - High Pressure Die Casting method on the mechanical and structural properties of castings intended for technology and mechanization means in forestry. Three groups of AlSi10MnMg alloy samples were formed for the experiment. Three different settings of mold cavity filling parameters were chosen. Two castings were made from each setting. Two samples were taken from two places on the casts. Thus, 12 pieces of samples were used for the experiment. An analysis of their mechanical properties was performed using a static tensile test. tensile strength, yield strength and ductility were evaluated. The microstructure was evaluated by light optical microscopy. The influence of process parameters on the quality of the casting was monitored from the point of view of the occurrence of errors, defects and the method and size of the exclusion of structural phases. The experimental results showed that the best results were obtained when the process parameters of the first group of samples were set. Their values are the closest to the customer's requirements.

The surface created by machining significantly affects the service life and functional reliability of the component. As part of this study, four different chip machining technologies were evaluated on the surface texture of the polymer material Ertacetal C. The samples were processed by turning, milling, grinding and polishing technologies, 5 samples for each technology. Within the given technology, different cutting conditions were chosen to compare the effect of cutting conditions on the resulting surface roughness. The machined surfaces were comprehensively evaluated on the basis of 16 profile and surface roughness parameters due to the practical use of the tested material. Surface texture measurements were performed on a Talysurf CCI Lite device. A non-contact method using a coher-ence correlation interferometer was used for the measurement. The obtained data were evaluated using TalyMap Platinum software. Graphical documentation of the machined surfaces was made using an Olympus DSX500 opto-digital metallographic microscope.