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 <TEX>$Al_{0.6}(Fe_{x}Cu_{1-x})_{0.4}(x=0.25, 0.50, 0.75)$</TEX> 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 <TEX>$600{^\circ}C$</TEX> for 1 h for as-milled alloy powders, the peaks of bcc <TEX>$AlCu_{4}\;and\;Al_{13}Cu_{4}Fe_{3}\;for\;x=0.25,\;bcc\;AlCu_{4}\;and\;Al_{5}Fe_{2}\;for\;x=0.50,\;and\;Al_{5}Fe_{2},\;and\;Al_{0.5}Fe_{0.5}\;for\;x=0.75$</TEX> are observed. After being annealed at <TEX>$500{^\circ}\;and\;600{^\circ}C$</TEX>for 1 h for leached specimens, these non-equi-librium phases transformed into fcc Cu and <TEX>$CuFe_{2}O_{4}$</TEX>phases for the x=0.25 specimen, and into bcc <TEX>${\alpha}-Fe,\;fcc\;Cu,\;and\;CuFe_{2}O_{4}$</TEX> phases for both the x=0.50 and the x=0.75 specimens. The saturation magnetization decreased with increasing milling time for <TEX>$Al_{0.6}(Fe_{x}Cu_{1-x})_{0.4}$</TEX> alloy powders. On cooling the leached specimens from <TEX>$800{\~}850^{\circ}C$</TEX>,\;the magnetization first sharply increase at about <TEX>$491.4{\circ}C,\;745{\circ}C,\;and\;750.0{\circ}C$</TEX> for x=0.25, x=0.50, and x=0.75 specimens, repectively.