A nickel based superalloy has been designed where the fcc γ Ni matrix is reinforced by two different ordered-fcc intermetallic compounds, γ' L12 Ni3Al and γ'' D022 Ni3V. Primary ageing at 900–1000 °C precipitated spherical L12 Ni3Al, whose volume fraction and size were controlled by altering the ageing temperature and time. Secondary ageing at 700 °C for 1–1000 h precipitated D022 Ni3V laths. The duplex precipitation increased hardness by up to 85 HV, with ∼ 500 MPa compressive proof strength maintained at 800 °C. Electron microscopy studied the Ni3Al precipitation and confirmed the form of the secondary Ni3V precipitates and their long term stability.
- mechanical properties