Stepwise Aging of Copper-Beryllium Alloys.

The effect of structural changes taking place during low-temperature aging of beryllium bronze, on the decomposition of oversaturated solid solution at a higher temperature and on the level of physical and mechanical properties of beryllium bronzes of different composition after combined aging is investigated. The kinetics of the initial stages of decomposition of oversaturated solid solution in the temperature range 150-240 degree C and its dependence on the content of surface-active magnesium is established. Stepwise aging results in a rise in the elasticity limit, relaxation stability (under static and cyclic loading), and cyclic strength. Preliminary low temperature aging lowers the energy of activation of subsequent high temperature aging compared with single-step high-temperature aging.