1982 Volume 46 Issue 9 Pages 917-924
A kinetic study of precipitation process in Cu-Be alloys has been carried out mainly by electrical resistivity measurements. The main results are as follows: (1) It has turned out that the data can not be analyzed with the rate equations proposed by Johnson-Mehl or Austin-Ricketts. (2) A new type of equation, y=1−exp{−(t⁄τ1)n1[1−e−(t⁄τ2)]n2}, has been proposed, and the continuous precipitation inside grains and the discontinuous precipitation at grain boundaries are separated from each other. (3) The time-exponent and time-constant in the rate equation have been determined and explained in terms of a model in which the rate of precipitation is controlled by a diffusion process necessary for the growth of rod-like precipitates and the number of growing precipitates increases exponentially. (4) The effects of solution treatment temperature and additional elements have been discussed.