Study of Preferred Orientation in FePd Alloy Prepared by Electrodeposition and Thermo-mechanical Processes

Abstract

FePd alloy has been considered as applications of potential magnetic recording and high temperature magnetic materials due to exhibiting the high magneto-crystalline anisotropy and good ductile property Thus controlling preferential orientation of the c-axis is very importance in magnetic applications In this thesis; as a result employs electrodeposition and thermo-mechanical process to induce the preferential orientation in FePd alloy Experimental results show that electrodeposited FePd films have and directions after annealing 500°C 600°C and 700°C for 1 hr respectively The value of coercivity (Hc) is decreased with increasing temperatures whereas the average grain size is increased This thesis firstly proposes the concept of the correlation coefficient to quantify the similarity of texture In comparison with X-ray diffraction (XRD) the experimental results of electron backscatter diffraction (EBSD) show that the correlation coefficient is close to 1 after 50% and 88% cold rolling in the step size range of 1 ?m–20 μm The results show that it can measure texture using a large scanning step of 20 μm at short time For thermo-mechanical process microstructures of cold-rolled 50% FePd alloy mainly exhibit twin lamella band and fine twin structures deformation textures are the Twin Copper {552} and Copper {112} Additionally the microstructures consisting of fine subgrains and shear bands are observed in the sample of 90% deformation which has the rolling textures of Goss {011} and Brass {011} orientations The intensity of Copper texture is decreased as increasing cold rolling degrees During annealing at ordering temperature 530oC full recrystallization occurs in 50% and 90% cold-rolled FePd alloy for 400 hr and 16 hr respectively Dominant texture in cold-rolled 50% sample changes from Copper type to (010)[1101] preferred orientation Recrystallization texture (054)[22-45] is observed in sample of 90% thickness reduction after full recrystallization and deformation textures of Goss and Brass are maintained After 16 hr annealing the maximum Hc exhibits 932 Oe with average grain size (1 57 μm) for 90% cold-rolled sample which is 519 Oe with average grain size (2 54 μm) for 50% cold-rolled specimen respectively After 700oC annealing at disordering temperature fully recrystallization of 50% cold-rolled FePd alloy take place for 48 hr and recrystallized textures exhibit (-1294)[401] and (558)[-1-1510] orientations In the case of 90% cold-rolled sample completely recrystallization occurs after 1 min annealing and the recrystallized texture is (6115)[2-713] orientation

Date of Award	2014 Aug 11
Original language	English
Supervisor	Jui-Chao Kuo (Supervisor)