Study of the initial stages of aging in beryllium bronzes

Abstract

For beryllium bronze there is no reliably established data on structural transformations and their correlation with changes in properties occurring in the initial stages of aging (decomposition). A study of these stages is important since on their development depends the process of later decomposition stages, as a result of which the most important properties of the bronze are formed. This paper reports on a study of the initial stages of decomposition with low-temperature aging (150-240/sup 0/C) on beryllium bronzes quenched from 770/sup 0/C. It is concluded that: on adding up to 0.4% Mg to beryllium bronze type Br BNT1.9, development of the advance precipitation or zone stage is accelerated during aging in the temperature range 150-240/sup 0/C, and this is revealed in a reduction in activation energy for the process of supersaturated solid solution decomposition; and, the structural state recorded in beryllium bronzes after low-temperature aging, corresponding to the initial stages of solid solution decomposition, is similar to that obtained in phases of decomposition with short-term, high-temperature aging.