抄録
The authors have reported on structure, recrystallization, and thermal stabilization of supersaturated solid solution of Al-Mn alloys which could be obtained by quenching from molten state. In this study, the distribution of Mn and the third elements such as Cu and Zn in these supersaturated solid solutions obtained by casting in wedge-shaped copper mold held at 0°C was examined by means of electron microprobe X-ray analyzer.
The results obtained were as follows.
(1) It was found that the distribution of Mn in the wedge-shaped specimens of Al-3% Mn, Al-3% Mn-3% Cu, and Al-3% Mn-2% Zn alloys were macroscopically uniform by chemical analysis, and also, dendritic structure of these alloys, which had been crystallized at high cooling rate (higher than about 800°C/sec), was almost microscopically homogeneous by X-ray microanalysis.
(2) It was shown that the segregation of Mn to the dendrite boundaries was effectively inhibited by the addition of these third elements even in case of relatively slow cooling rate.
(3) The distribution of the third additional elements was not so uniform as that of Mn, and particularly, the segregation of Cu to the dendrite boundaries was remarkable.
