On the stability of Ni₃Ge

Ni₃Ge-containing nickel-germanium alloys with 12.10 to 16.8 at. % Ge were investigated. Nickel-saturated Ni₃Ge had a lattice parameter of 3.57015 × 10⁻¹⁰ m and contained 22.5 at. % Ge over the temperature range 650 to 1100 °C. However, the precipitates in the initial stages contained 24.44 at. % Ge and were almost cubic in shape. The strengthening effects of Ni₃Ge were appreciable. In alloys containing higher percentages of germanium, precipitates were observed in as-quenched specimens. The hardness after quenching was high and did not change appreciably with time. Hardness was reduced in the presence of aluminum.