Susumu Ikeno1, Shigeoki Saji2 and Shigenori Hori2
1Graduate School, Osaka University, Suita
Effects of third elements (0.04, 0.08 and 0.3 at%Zr, 0.5 at%Mg and 0.5 at%Be) on the cellular precipitation in Cu-5 at%Ti alloys were studied by microhardness measurement and optical and electron microscopy observation. The results are summarized as follows.
(1) On ageing at 450°C, the cellular precipitate reaction was extremely retarded by the addition of Zr, and only small amounts (5∼6%) of cellular precipitates were observed even in a very later stage of the ageing process in 0.3 at%Zr alloys.
(2) The growth rate of cellular precipitates was found to decrease exponentialy with increase in Zr content.
(3) The wave lengths of modulated structures were not charged by the small addition of Zr. Accordingly, the effects of Zr addition on the increase of hardness (due to modulated structure) were not observed.
(4) No effect of addition of Mg on the cellular precipitation was observed, while the cellular precipitation was slightly retarded by the addition of Be.
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