Equal channel angular pressing of wire-formed Al6063 by PU rubber-assisted procedure

Expanding suitable severe plastic deformation processes seems essential to design lightweight wire-formed materials for emerging demands. In this regard, 6063 aluminum alloy in the form of wire was processed successfully by polyurethane rubber assisted-equal channel angular pressing up to 16 passes by route BC. It was found that significant improvement of hardness and strength is achieved at the initial passes due to the increment of material’s dislocations density which leads to the crystallite size decrease and lattice microstrain increase. Also, subsequent passes improve the mechanical properties with a gentle rate due to the saturation of dislocation strengthening. The fractography analysis indicated that the ductile fracture mode of the annealed aluminum decreases by imposing the ECAP process. It is related to the formation of cleavage and rive patterns and the reduction in the number and size of the dimples compared to the initial condition. Eventually, X-ray diffraction findings showed that by adding pass numbers, the isotropy degree of the aluminum sample enhances because of the lowest diffraction scattering.

Structural and phase composition modification of nanocrystalline Nd14Fe79B7 alloy during thermomagnetic measurements

Changes in the microstructure parameters, phase composition and magnetic properties of rapid quenched Nd-rich Nd14Fe79B7 alloy caused by thermomagnetic measurement (TM) were studied using XRD methods of phase analysis, crystallite size and lattice microstrain determination. The observed changes were analyzed between the optimized magnetic state of this alloy and state after TM up to 800oC. Measurement of magnetic properties was carried out on the SQUID magnetometer at ambient temperature. The obtained experimental results show that the investigated alloy in the optimized magnetic state has nearly monophase composition with predominant content of hard magnetic Nd2Fe14B phase (up to 95 mass %) with mean crystallite size below 60 nm. In the state after TM, it was found that the decreased amount of Nd2Fe14B phase (75 mass%), increased amount of soft magnetic phases, predominantly of Fe7Nd5, formation of Nd-rich oxide Nd2O3 phase, as well as grain growth have caused the observed quality loss of hard magnetic properties.