Microstructural evolution of a recycled aluminum alloy deformed by equal channel angular pressing process

The microstructural evolution of a recycled aluminum alloy after equal channel angular pressing (ECAP) up to four passes was investigated using X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM). Microhardness tests were performed to determine the associated changes in mechanical properties. An ultrafine-grained material has been obtained with a microstructure showing a mixture of highly strained crystallites. A high density of dislocations was achieved as a result of severe plastic deformation (SPD) through the die. Changes in mechanical behavior are also revealed after ECAP due to strain hardening. Thermal analysis and TEM micrographs obtained after annealing indicate the succession of the recovery, recrystallization, and grain growth phenomena. Moreover, the energy stored during ECAP may be related to the dislocation density introduced by SPD. We finally emphasize the role played by the precipitates in this alloy.     

Morphological and molecular aspects of Ceratomyxa ghannouchensis n. sp. and C. pallida Thélohan 1894 infecting the bogue,Boops boops (l.)

We report herein the molecular and morphological characteristics of two myxozoan parasites, Ceratomyxa ghannouchensis n. sp. and Ceratomyxa pallida Thélohan, 1894 infecting the gallbladder of the bogue, Boops boops (Linnaeus, 1758) in the Gulf of Gabès off the Tunisian coast. Mature myxospores of C. ghannouchensis were stubby with a convex anterior end and almost straight to slightly concave posterior one. Mature myxospores measured 5.8 ± 0.4 (5–7) µm in length and 11.7 ± 0.3 (11–13) µm in thickness. Valves were unequal in size with one occasionally tapering to a greater degree than the other. The polar capsules were equal in size, spherical in shape and measured 2 ± 0.2 (1.8–2.8) µm in diameter. Infection with C. pallida occurs as spherical to elongated mono-, di- or trisporic plasmodia floating in the bile. Mature myxospores were crescent-shaped with two symmetrical shell valves with rounded edges. The myxospores measured 6 ± 0.5 (5–7) µm in length and 28.5 ± 2.5 (26–33) µm in thickness. The polar capsules were spherical, equal in size and measured 3 ± 0.3 (2.7–3.3) µm in diameter. Based on the SSU rDNA partial sequence, C. ghannouchensis n. sp. and C. pallida appeared in the same subclade with Ceratomyxa leatherjacketi and Ceratomyxa tunisiensis.

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