Papers by Keyword: X-Ray Mapping

Abstract: Phosphates are widely used as a substitute material for bones and teeth in medical sciences. It is known that phosphate and iron have a strong affinity for each other. In this study, process of formation of iron phosphate was closely monitored using scanning electron microscope equipped with backscatter electron image and energy dispersive X-ray imaging facilities. Different stages of formation of the iron-phosphate material in an environment rich in phosphate and iron were observed. Initial stage of absorbing iron on phosphate-rich substrate is the most important stage of the entire process. X-ray mapping provides strong visual evidence to track down the dispersion of major elements during this process.

Abstract: Nb-20Mo-15Si-5B-20(Cr,Ti) alloys have been subjected to annealing treatment for 2 hours in a range of temperatures from 700 to 1400oC and quenched in water to perform the microstructural characterization for these two new alloys. As cast structure consists of a solid solution phase, , and silicides (Nb5Si3) in both alloys but Cr alloy also contains NbCr2 and Nb3Si phases. Heating to higher temperature introduces Ti silicides in the microstructure for Ti alloy. The oxidation in air has been conducted on these alloys in the same temperature range for 24 hours. Weight gain per unit area as a function of temperature provides the oxidation curves while characterization techniques using SEM, EDS on SEM, x-ray mapping, and XRD has yielded the analyses of the oxide scale. The scale consists of various oxides of Nb, Mo, Cr, Si, and Ti. Cr alloy appears to offer higher oxidation resistance in the selected range of oxidation temperatures.

Abstract: In this study, severe plastic straining through equal-channel angular pressing (ECAP) is imposed on age-hardenable Al-Mg-Si alloys having two different compositions of excess Si or Mg in the Al-Mg2Si pusedo-binary system. Thereafter, the alloys are subjected to aging and the microstructures are examined using transmission electron microscopy. It is shown that the precipitation behavior is significantly changed through application of ECAP.