Tensile Properties of Cast Alloy IN625 in Relation to d Phase Precipitation

The relationship between the tensile properties and δ (delta) phase precipitation in cast alloy IN625 was investigated in this paper. Although the influences of δ phase on the mechanical properties have been pointed out in our previous work, the relationship is still not directly determined due to the coexistence of γ″ (gamma double prime) and δ precipitates. In order to exclude the effect from γ″ phase, various fractions of δ precipitates with few γ″ precipitates were obtained by a set of experimental alloys aging at 750 °C, and tensile tests were conducted in parallel. The results showed that both yield strength and ultimate tensile strength increased nearly in linear with increasing δ phase fraction, while the elongation was relatively and limitedly affected by δ precipitation when the area fraction of δ phase was above 10%.