Two-phase intermetallic alloy Ni3(Al, Si):

Yield stress in compression (0.2% flow stress) from ambient temperature up to 800 °C has been studied on Ni3(Al, Si) alloy with the atomic composition Ni78Al11Si11. When annealed at 1000 °C, the alloy has a pure L12 (γ′) ordered structure. After subsequent annealing at 750 °C, the disordered solid solution of Al and Si in Ni (face centred cubic, γ) precipitates in fine coherent particles. Calorimetry helps to describe the various phase transformations necessary to obtain the last microstucture. Solute addition of Si, which replaces Al atoms, increases the 0.2% flow stress of Ni3Al in the fully γ′ microstructure. The γ precipitation shifts the peak stress towards higher temperatures and stresses.