Rod milling과 Chemical Leaching에 의해 제작된 비평형 Al(Fe-Cu) 합금 분말의 결정화 및 자기적 특성

Abstract

We report the crystallization and magnetic properties of non-equilibrium Al0.6(FexCu1-x)0.4(x = 0.25, 0.50, 0.75) alloy powders produced by rod-milling as well as by new chemical leaching. X-ray diffractometry, transmission electron microscopy, differential scanning calorimetry and vibrating sample magnetometry were used to characterize the as-milled and leached specimens. After 400 h or 500 h milling, only the broad peaks of nano bcc crystalline phases were detected in the XRD patterns. The crystallite size, the peak and the crystallization temperatures increased with increasing Fe. After being annealed at 600℃ for 1 h for as-milled alloy powders, the peaks of bcc AlCu4 and Al13Cu4Fe3 for x = 0.25, bcc AlCu4 and Al5Fe2 for x = 0.50, and Al5Fe2 and Al0.5Fe0.5 for x = 0.75 are observed. After being annealed at 500℃ and 600℃ for 1 h for leached specimens, these non-equilibrium phases transformed into fcc Cu and CuFe2O4 phases for the x = 0.25 specimen, and into bcc α-Fe, fcc Cu, and CuFe2O4 phases for both the x = 0.50 and the x = 0.75 specimens. The saturation magnetization decreased with increasing milling time for Al0.6(FexCu1-x)0.4 alloy powders. On cooling the leached specimens from 800~850℃, the magnetization first sharply increased at about 491.4℃, 745℃, and 750.0℃ for x = 0.25, x = 0.50, and x = 0.75 specimens, repectively.