Precipitation in a Cu–4Ti–2Be alloy

It is known that the binary Cu–2 wt.% Be alloy can be strengthened by ageing its supersaturated solution at 523 K. The increase in the strength arising from ageing is because of the formation of GP zones. The same level of strength is achieved by ageing the supersaturated solid solution of a dilute binary Cu–4 wt.% Ti alloy at 723 K. In contrast to Cu–2 wt.% Be alloy, the increase in strength in this alloy occurs on account of spinodal decomposition of the as-quenched microstructure through the mechanism of clustering and ordering. In the present study, decomposition of a supersaturated solid solution of the ternary Cu–4 wt.% Ti–2 wt.% Be alloy was studied. Whereas ageing of this alloy at 523 K resulted in the formation of GP zones like in a Cu–2 wt.% Be alloy, ageing at 723 K resulted in a spinodally decomposed microstructure as in a Cu–4 wt.% Ti alloy. The decomposition of the ternary alloy at the two temperatures by two different mechanisms indicates that Be and Ti in solution in Cu act, more or less, ...