Strengthening of AA5754 aluminum alloy by DRECE process followed by annealing response investigation

In this study, a dual rolls equal channel extrusion (DRECE) process has been applied for improving the mechanical properties of the 5754 alloy. Supplementary experiments involving metallography, electron backscattered diffraction (EBSD), and XRD tests were carried out to evaluate the effect of the DRECE process. XRD analysis showed that the maximum dislocation density was achieved after six DRECE passes, which were accompanied by the formation that is typical for low-strain structures. The increasing dislocation density, as well as grain refinement throughout DRECE deformation, resulted in an increase in the mechanical properties. Annealing of the as-deformed sample resulted in grain growth and strength reduction.Web of Science132art. no. 30

Characteristics of the Mg-Zn-Ca-Gd alloy after mechanical alloying

Magnesium-based materials are interesting alternatives for medical implants, as they have promising mechanical and biological properties. Thanks to them, it is possible to create biodegradable materials for medical application, which would reduce both costs and time of treatment. Magnesium as the sole material, however, it is not enough to support this function. It is important to determine proper alloying elements and methods. A viable method for creating such alloys is mechanical alloying, which can be used to design the structure and properties for proper roles. Mechanical alloying is highly influenced by the milling time of the alloy, as the time of the process affects many properties of the milled powders. X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS) were carried out to study the powder morphology and chemical composition of Mg65Zn30Ca4Gd1 powders. Moreover, the powder size was assessed by granulometric method and the Vickers hardness test was used for microhardness testing. The samples were milled for 6 min, 13, 20, 30, 40, and 70 h. The hardness correlated with the particle size of the samples. After 30 h of milling time, the average value of hardness was equal to 168 HV and it was lower after 13 (333 HV), 20 (273 HV), 40 (329 HV), and 70 (314 HV) h. The powder particles average size increased after 13 (31 m) h of milling time, up to 30 (45–49 m) hours, and then sharply decreased after 40 (28 m) and 70 (12 m) h

CHARACTERIZATION OF PRECIPITATES FORMED IN THE ALUMINUM ALLOY WITH ANTIMONY

The aim of the article was to identify and characterize the precipitates formed in the aluminum alloys with the addition of antimony. The performed investigation was on the casting aluminium alloy based on ENAC-AlMg5Si2Mn (ENAC-51500) used in the automotive industry with the addition of antimony in an amount of 0.2 % for the first sample and 1.2 % for the second one. The main research technique was scanning electron microscopy, in order to evaluate the morphology and precipitates in the investigated samples, the backscattered electrons were used. Performed research allowed to determine the effect of the addition of antimony on the morphology of formed precipitates

Structure and Properties of the Multicomponent and Nanostructural Coatings on the Sintered Tool Materials

This chapter presents a general characteristic of sintered tool materials, in particular sintered sialons, nitride ceramics, injection-moulded ceramic-metallic tool materials and cemented carbides and a general characteristic of their surface treatment technology and especially chemical vapour deposition (CVD) and physical vapour deposition (PVD) techniques. The results of our investigations in technology foresight methods concerning the development prospects of surface engineering of sintered tool materials are presented. In the next subsection, we discuss the outcomes of multifaceted research carried out with advanced materials engineering methods, including high-resolution transmission electron microscopy, into the structure and properties of multicomponent, graded and multilayer coatings on the investigated tool materials, including the newly developed injection moulded ceramic-metallic tool materials. Special attention was drawn to a one-dimensional structure of the studied PVD and CVD coatings and its impact on the properties of coatings

INFLUENCE OF THE PVD PROCESS PARAMETERS ON ZNO: AL THIN FILMS

In recent years a growing interest in searching new material for producing Transparent Conductive Layers (TLC) is observed. ZnO:Al thin films are this type material, interesting due to wide range of potential applications where it can be applied like: transparent electrodes, gas sensors, thin film transistors, sensor devices, electroluminescent diodes and others. The aim of this paper is to discuss influence of the ZnO:Al film deposition parameters of PVD magnetron sputtering method on TCL structure and its chemical composition. It contains description of the ZnO:Al PVD magnetron sputtering deposition method. It discusses results obtained from the analysis of the microstructure of ZnO:Al thin films using a high resolution scanning electron microscope, layers' surface topography determined with atomic force microscope and results of chemical composition analyses

Structure and Magnetic Properties of Fe-B-La-Al Alloy

Nanocrystalline magnetic materials are of great interest in order to meet the needs of electronics and electrical engineering. There are many possibilities to modify the synthesis parameters and chemical composition in order to obtain the most desirable magnetic properties and microstructure. The paper discusses an iron-based alloy with the addition of boron lanthanum and aluminium. The alloy was obtained by induction melting and casting with a melt-spinner. The main purpose of the work was to analyze the structure and properties of both the starting alloys in the form of ingots and the obtained tapes. X-ray diffraction (XRD), scanning electron microscopy (SEM), vibration magnetometry (VSM) and microhardness measurements using the Vickers method were carried out

Microstructure and Mechanical Properties of Spark Plasma Sintered Mg-Zn-Ca-Pr Alloy

Alloys based on magnesium are of considerable scientific interest as they have very attractive mechanical and biological properties that could be used to manufacture biodegradable materials for medical applications. Mechanical alloying is a very suitable process to obtain alloys that are normally hard to produce as it allows for solid-state diffusion via highly energetic milling, producing fine powders. Powders obtained by this method can be sintered into nearly net-shape products, moreover, their phase and chemical composition can be specifically tailored. This work aims to investigate the effect of milling time on the density, microstructure, phase composition, and mechanical properties of Mg-Zn-Ca-Pr powders processed by high energy mechanical alloying (HEMA) and consolidated by spark plasma sintering (SPS). Thus, the results of XRD phase analysis, particle size distribution (granulometry), density, mechanical properties, SEM investigation of mechanically alloyed and sintered Mg-Zn-Ca-Pr alloy are presented in this manuscript. The obtained results illustrate how mechanical alloying can be used to produce amorphous and crystalline materials, which can be sintered and demonstrates how the milling time impacts their microstructure, phase composition, and resulting mechanical properties

Recovery of metals from printed circuit boards by means of electrostatic separation

Without the use of appropriate recycling technologies, the growing amount of electronic waste in the world can be a threat to the development of new technologies, and in the case of improper waste management, may have a negative impact on the environment. This is due to the fact that this waste contains large amounts of valuable metals and toxic polymers. Therefore, it should be recycled in accordance with the assumptions of the circular economy. The methods of mechanical recovery of metals from electronic waste, including printed circuits, may be widely used in the future by waste management companies as well as metal production and processing companies. That is why, a well-known and easily applicable electrostatic separation (ES) method was used to recover metals from printed circuit boards. The grain class of 0.32 - 0.10 mm, obtained after grinding the boards, was fed to a separator. Feed and separation products were analyzed by means of ICP-AES, SEM/EDS and XRD. The concentrate yield obtained after electrostatic separation amounted to 32.3% of the feed. Its density was 11.1 g/cc. Out of the 91.44% elements identified in the concentrate, over 90% were metals. XRD, SEM observations and EDS analysis confirmed the presence of non-metallic materials in the concentrate. This relatively high content of impurities indicates the need to grind printed circuit board into grain classes smaller than 0.32-0.10 mm

Effect of spray distance on the microstructure and corrosion resistance of WC - based coatings sprayed by HVOF

Cermet coatings provide protection against aggressive operating environment of machine and device elements, such as corrosion, wear or high-temperature conditions. Currently WC-based cermet coatings are frequently used in the different industry branches. In this work, conventional WC-based powders (WC-Co and WC-Co-Cr) were sprayed with High Velocity Oxy Fuel (HVOF) onto AZ31 magnesium alloy with different spray distances (320 and 400 mm). The aim of the research was to investigate the effect of the spray distance on the microstructure of the coatings, phase composition and electrochemical corrosion resistance. Results revealed that higher spray distance results in greater porosity, 1.9% and 2.3% for 320 mm and 2.8% and 3.1% for 400 mm in case of WC-Co and WC-Co-Cr coatings, respectively. Also the influence has been observed for coatings microhardness, c.a. 1300 HV0.3 for shorter spray distance, whereas for longer one it was less than 1100 HV0.3. The corrosion resistance estimated in potentiodynamic polarization measurements was the best for WC-Co-Cr coating deposited from the shorter spray distance, corrosion current density was equal to 2.9 µA·cm-2 and polarization resistance was equal to 8424 Ω∙cm2