急冷凝固したAl- (0.2～2wt%) Zr合金の時効性について

The studies on recrystallization of Al-Zr alloys have been made by many investigators since Harrington's report in 1949. These studies showed that age hardening property was found in these alloys. However, the authors were interested with the further examination of this property in the above alloys containing much more solute of Zr. The property was investigated on super-saturated solutions obtained by quenching of uniform molten bath of Al-Zr alloys.The results obtained were as follows:(1) According to the results of electrical resistivity measurements, it would be possible in these experiments to get the solid solubility limit of Zr in Al up to about 1.2wt.% by quenching of molten Al-Zr alloys.(2) Age hardening of these alloys containing more than 0.4wt.% of Zr was remarkable and it increased to the maximum at about 1.2wt.%.(3) Precipitation of Zr took please at 300°C for 1hr. annealing and the maximum precipitation hardening was given at about 400-450°C.(4) Inpurities such as Fe, Si, etc. seemed to have deep effects on the precipitated structures of these alloys.