Structural and quantitative analysis of die cast AE44 magnesium alloy

Purpose: The main objective of this study was development of determination of phase fraction methodology in cast magnesium alloy containing aluminum and rare earth elements. Design/methodology/approach: The study was conducted on magnesium alloy containing 4 %wt. aluminum and 4 %wt. mixture of rare earth elements (mischmetal) in the as-cast condition. The mischmetal includes cerium, lanthanum, neodymium and praseodymium. In this study, several methods were used such as: optical light microscopy, quantitative metallography, scanning electron microscopy and X-ray diffraction. The Rietveld method with Hill and Howard procedure was applied for determination of lattice parameters and phase abundance. Findings: The microstructure of investigated alloy consists of α-Mg solid solution, globular, lamellar and acicular precipitations of Al11RE3 and Al2RE phases. The results show that the accurate determination of phase contents in AE44 alloy can not perform using quantitative metallography. In this purpose X-ray investigations should be applied. Research limitations/implications: Developed methodology will be used to quantitative phase analysis of investigated alloy after creep tests and die cast with different parameters. Practical implications: AE44 magnesium alloy is used in automotive industry. Moreover, this alloy has a new potential application and results of investigations may be useful for preparing optimal technology of die casting. Originality/value: Procedure described in this paper may be useful as the best experimental techniques for quantitative phase analysis of the intermetallic phases occurring in the AE series magnesium alloys

Novel piezoelectric paper based on SbSI nanowires

A novel piezoelectric paper based on antimony sulfoiodide (SbSI) nanowires is reported. The composite of tough sonochemically produced SbSI nanowires (with lateral dimensions 10–100 nm and length up to several micrometers) with very flexible cellulose leads to applicable, elastic material suitable to use in fabrication of, for example, piezoelectric nanogenerators. For mechanical energy harvesting, cellulose/SbSI nanocomposite may be used. Due to its high values of electromechanical coefficient (k33 = 0.9) and piezoelectric coefficient (d33 = 1 9 10-9 C/N), SbSI is a very attractive material for such devices. The preliminary investigations of a simple cellulose/SbSI nanogenerator for shock pressure (p = 3 MPa) and sound excitation (f = 175 Hz, Lp = 90 dB) allowed to determine its open circuit voltage 2.5 V and 24 mV, respectively. For a load resistance equal to source impedance (ZS = 2.90(11) MX), maximum output power density (PL = 41.5 nW/cm3 for 0.05-mm-thick sheet of this composite) of the cellulose/SbSI nanogenerator was observed. Cellulose/SbSI piezoelectric paper may also be useful to construct gas nanosensors and actuators