Coercive force and structure in a Co-Fe-Au alloy

Abstract

Strip samples of 82 Co-12 Fe-6 Au alloy were solution annealed and quenched to produce a supersaturated γ (fcc) structure. The samples were then cold worked to 50, 75, and 90 pet R.A. by rolling. Magnetic measurements showed that cold work increasedH _c from the 1 oe level in well annealed samples to about 5 oe for all amounts of cold work, and that annealing of the cold worked samples further increasedH ₁ to maximum values of 9, 11, and 13 oe for the 50, 75, and 90 pet cold worked samples, respectively. The structural changes produced by annealing were followed quantitatively by light metallography. The progress of a discontinuous precipitation reaction, which simultaneously relieved the supersaturation of the solution treated matrix and effectively recrystallized the cold worked matrix was found to correlate well with the measured increases in coercive force. Electron transmission and diffraction verified that fine particles of gold on the order of 1000Å in diam were formed by the discontinuous precipitation.