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The Cu-0.36Cr-0.15Zr alloy was prepared by solid solution, continuous extrusion and cold deformation. The microstructural evolution, microhardness and the thermal analysis were examined for the alloy after annealing treatment at different temperatures ranging from 300 oC to 700 oC. Experimental results show that the microstructure of the alloy remains stable after annealed below 500 oC due to the pinning effect of dislocations from the nanoscale precipitates. However, recrystallization and grain growth took place after a 600 oC annealing treatment when the precipitates grew up and lose inhibition of movement of dislocations and grain boundaries. Meanwhile, the higher dislocation density and finer grains introduced by continuous extrusion accelerate the recrystallization process compared with that prepared by the traditional rolling process.

Atom probe tomography (APT) coupling high-resolution transmission electron microscopy (HRTEM) was used to analyze the fraction and compositions of different nanoparticles in two-stage double peaks aging process of Al−Zn−Mg alloy. Al content is found to be closely related to the size of nanoparticles and it can be greater than ~ 50.0 at. % in the nanoparticle with the equivalent radius under ~ 3.0 nm. Correspondingly, Al content of the nanoparticle, with the equivalent radius over ~ 5.0 nm, is measured under ~ 40.0 at. %. Evolution from Guinier–Preston (G.P.) zone to η phase is a growing process where Mg and Zn atoms enter the nanoparticle, therefore rejecting Al atoms. G.P. zones can take up a number fraction of ~ 85.0 and ~ 22.7% of nanoparticles in the first and second peak-aged samples, respectively, and even in the over-aged (T73) sample, they can still be found. As aging time increases, fraction of η′ phases monotonically rises to the peak value (~ 54.5%) in the second peak-aged state and then drops, which is significant for the second hardness peak and directly proves their function as the transitional medium. In T73 state, ~ 63.3% nanoparticles compose of η phases, which were measured to still contain ~ 10.2 to ~ 36.4 at. % Al atoms.

We have studied magnetization reversal behaviors of diamond-shaped NiFe nanofilm elements with different length-to-width ratios (LWRs) between long and short diagonals by micromagnetic simulation. The results show that the reversal process of the diamond-shaped element strongly depends on the LWR. If the LWR is smaller than 2, the reversal starts at the element edge, but it starts from the center of the element with larger LWR. With a bias field and when the LWR is larger than 2, all the elements experience a similar reversal process, which is simple and unique. In addition, the switching field becomes stable and nearly constant. These results suggest that the diamond-shaped NiFe nanofilm element can be potentially used in magnetic random access memory.

We have found that in-plane magnetostriction characteristics at low fields can be greatly improved by an oblique sputtering technique. We report a study of deposition of in-plane anisotropic TbFe giant magnetostrictive films by dc magnetron oblique sputtering, including the influences of deposition angle on TbFe film magnetic and magnetostrictive performances. The in-plane magnetization of TbFe films at 1600 kA/m is drastically increased with a change of deposition angles from 90/spl deg/ to 15/spl deg/. Magnetic domain structures explored by magnetic force microscopy indicate that the easy magnetization directions of the films can be gradually changed from perpendicular to the film plane at sufficiently shallow deposition angles. The in-plane magnetostrictive coefficients /spl lambda/ at 16 kA/m also can be increased by decreasing the deposition angles from 90/spl deg/ to 15/spl deg/. The significant variation in the in-plane magnetic and magnetostrictive performances can be explained by the decrease of perpendicular anisotropy of TbFe films.