Effects of Addition of B and P on the Cellular Precipitation in Ni–Sn and Cu–Ni–Sn Alloys

Abstract

The influence of the additions of B and P on the cellular and intragranular precipitation in Ni-8-15 mass %Sn and Cu-80 mass %Ni-8 mass %Sn alloys was investigated by quantitative metalographic methods.By the additions of B and P, the intragranular precipitation was slightly retarded, while the cellular precipitation was significantly suppressed. The suppressing effects of B and P depended upon the Ni concentration in the Cu-Ni-Sn alloys and were especially large in the 40-60%Ni alloys. These effects increased with increasing amount of addition. It is considered that B and P segregate in the grain boundaries and suppress the nucleation and growth of cells.

Effects of B Additions on the Intragranular and Cellular Precipitations in a Cu–Be Alloy

“…Moreover, the authors have reported that the B atoms added in Ni-Sn and Cu-Ni-Sn alloys suppressed remarkably the growth of grain boundary cells (4). Since the B atoms added in Ni or Cu-Ni base alloys tend to segregate at grain boundaries(5)(6), these segregated atoms must have suppressed the nucleation and growth of cells.…”