| Cu-1.9% Be-0.2% Co alloy has excellent mechanical properties such as tensile strength, hardness and fatigue strength(spring characteristics), and is widely used for spring applications. In the present study, heat-treating conditions were investigated in relation to mechanical properties and the micro-structure of the aged alloy. Heat-treating conditions for specimens of 35% final cold-reduction, namely, aging for 2 hours at 330℃ after solution anneal of 0.8㎜ thick specimens for 15 minutes at 800℃ resulted in optimum mechanical properties of 136 ㎏/㎟ tensile strength, 440 micro-Vickers hardness, 2% elongation and 85 ㎏/㎟ fatigue strength. The aging sequence of the alloy established by thin-foil transmission electron microscopy is α→ G.P. zones→γ¹→γ in within grain and α→γ at grain boundaries. |
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