Deformation and fracture of AMC under different heat treatment conditions and its suitability for incremental sheet forming

By evaluating the deformation and fracture mechanisms of a 6092Al alloy metal matrix composite reinforced with 17.5p vol. % SiC particles (6092Al/SiCp), this paper investigates the applicability of using incremental sheet forming (ISF) process to form the 6092Al/SiCp aluminium matrix composite (AMC) under different heat treatment conditions. Tensile tests were carried out at different strain rates to study the microstructure and topography of the 6092Al/SiCp sheet by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The tensile test results and the morphology of the fracture showed that the 6092Al/SiCp to T6 condition has low elongation to fracture (0.08), whilst much improved elongation can be achieved after annealing to O-condition. A series of ISF tests were carried out to form 6092Al/SiCp sheet into a truncated hyperbolic shape with different ISF process parameters. At T6 condition, ISF testing showed unsatisfactory results for the 6092Al/SiCp with a low wall angle (31.2ο) to fracture and a significant amount of springback. After annealing to O-condition, a much increased wall angle was achieved with reduced springback due to the enhanced ductility of the 6092Al/SiCp material. Microstructural and topographic evaluation of the 6092Al/SiCp parts formed by ISF allowed a detailed characterisation of brittle and ductile fractures for different heat treatments. The obtained ISF results and evaluation enabled the recommendation of optimum ISF operational windows for 6092Al/SiCp materials

Effect of Sr+ ion Concentration on Microstructure and Dielectric properties of Barium Strontium Titanate Ceramics

Ba1-xSrxTiO3(BST) solid solution with x=0.3,0.4 and 0.5 were prepared by sol-gel method. (Ba, Sr) acetate and Titanate isopropoxide were used as a starting material. XRD patterns confirmed the formation of tetragonal perovskite structure and cubic structure.The FESEM images showed that the particles size reduced when strontium concentration increased. Particles size influence on dielectric constant which observed that with decreasing value dielectric constant due to increased frequency and strontium ion Sr+. The high value of dielectric constant observed at low frequencies and reduced concentration of Sr+

Evaluation of Water Quality Parameters for Shatt Al-Basrah Canal in Basrah Authorities

A significant increase in freshwater demand has been reported recently due to several factors such as population growth, industrialization, rising living standards and global warming effects. As a direct result of that, numerous water crises have occurred around the world especially in downstream countries such as Iraq. Due to the previous reasons, water in terms of quality and quantity considered as a first priority by the Iraqi government. This study focuses on Basrah city, which is located in the south region. The purpose of this research is evaluating the physicochemical qualities of water from the Shatt Al-Basrah Canal to evaluate its suitability to be used for domestic or industrial uses. Data gathered from two sampling stations located on the canal to measure the physicochemical characteristics of the water such as pH, Ca, Mg, PO4, Cl, SO4, DO, NO3, TDS, and EC. With this specific purpose, water samples were collected from the study area, and the water quality has been evaluated. Water samples were collected during six months period during 2013 for assessment purposes. The results of the analysis were assessed according to international water standards for drinking water. From these results of this study, it is often asserted that there is a water pollution in the Shatt Al-Basrah canal and therefore immediate protective actions need to be utilized to minimize the pollution and improve water quality

Review on the influence of process parameters in incremental sheet forming

Incremental sheet forming (ISF) is a relatively new flexible forming process. ISF has excellent adaptability to conventional milling machines and requires minimum use of complex tooling, dies and forming press, which makes the process cost-effective and easy to automate for various applications. In the past two decades, extensive research on ISF has resulted in significant advances being made in fundamental understanding and development of new processing and tooling solutions. However, ISF has yet to be fully implemented to mainstream high-value manufacturing industries due to a number of technical challenges, all of which are directly related to ISF process parameters. This paper aims to provide a detailed review of the current state-of-the-art of ISF processes in terms of its technological capabilities and specific limitations with discussions on the ISF process parameters and their effects on ISF processes. Particular attention is given to the ISF process parameters on the formability, deformation and failure mechanics, springback and accuracy and surface roughness. This leads to a number of recommendations that are considered essential for future research effort

Investigation of the effect of forming parameters in incremental sheet forming using a micromechanics based damage model

The incremental sheet forming (ISF) process is considered as a feasible solution for forming a variety of small batch and even customised sheet components. The quality of an ISF product is affected by various process parameters, e.g. sheet material, step-down, feed rate, tool diameter and lubricant. To produce an ISF part of sufficient quality and accuracy without defects, optimal parameters of the ISF process should be selected. In the present work, experiments and FE analyses were conducted to evaluate the influence of the main ISF process parameters including the step-down, feed rate and tool diameter on the formability and fracture of two types of pure Ti (grade 1 and 2). The Gurson–Tvergaard-Needleman (GTN) damage constitutive model with consideration of stress triaxiality was developed to predict ductile fracture in the ISF process due to void nucleation, growth and coalescence. It was found that the ISF parameters have varying degrees of effect on the formability and fracture occurrence of the two types of pure Ti, and grade 2 pure Ti sheet is more sensitive than grade 1 Ti sheet to the forming parameters due to low ductility

Influence of Sintering Temperature on Ferroelectric Ba0.7Sr0.3TiO3 Microstructure, Grain Size, and Electrical Properties

Barium strontium titanate is a ferroelectric material that is currently attracting much attention because it has high dielectric constant, low dissipation factor, tunable dielectric constant at microwave frequencies, and low-leakage current.The Ba0.7Sr0.3TiO3 compound studied in the present paper was synthesised using sol-gel method. The ferroelectric Ba0.7Sr0.3TiO3 was prepared using the sol-gel method, with barium and strontium acetate as a source for Ba and Sr as well as Ti(IV) isopropoxide as a source for Ti. The solvent used in this paper was acetic acid whereas 2- methoxyethanol has was used a stabiliser for Ti (IV) isopropoxide. Moreover, the effect of changing the electrical properties, the nanocrystal structure, and the particle size of ferroelectric Ba0.7Sr0.3TiO3 on its sintering temperature phase was investigated. The XRD results showed that sintering Ba0.7Sr0.3TiO3 at 900, °C 1000 °C, and 1100 °C occurred in a tetragonal phase. The sintering temperature affected the lattice constant and tetragonality of the material, where increasing sintering temperature decreased the tetragonality and the lattice constant. The dielectric properties of Ba0.7Sr0.3TiO3 sintered at 1100 °C were superior to that of the ferroelectric sample sintered at 1000 °C. The Curie temperature occurred at (28–32) °C when the dielectric constant was plotted as a function of temperature

Humidity Sensing Properties of Ferroelectric Compound Ba0.7Sr0.3TiO3 Thin Films Grown by Pulsed Laser Deposition

BaSrTiO3(BST) is a solid solution prepared by Sol-Gel method. A ternary compound of BST is composed of from solid solution BaTiO3 and SrTiO3. BST thin films prepared by PLD method and their humidity sensing characteristics have been investigated. The films were formed on Si substrates with Au electrodes. XRD pattern showed tetragonal phase and no significant change between film and bulk. SEM revealed a uniform distribution of cubic particles shape and nanoparticles size. Capacitive and Resistive humidity sensors were made based on BST/Si thin film used co- planer form and the corresponding sensing properties were investigated. Experimental results showed on that the sensor exhibited high sensitivity and good stability. The humidity relative increased then the capacitive increased and resistivity decreased