Work

Mechanical properties and fracture mechanism of high-strength FGH4097 superalloys prepared by hot oscillatory pressing

Year: 2025

Type: article

Abstract: A powder metallurgy (PM) nickel-based superalloy of FGH4097 with Φ160mm × 90mm was prepared by hot oscillatory pressing (HOP) method and heat treatment process. The mechanical properties and fracture mechanism of FGH4097 superalloys at room temperature and 650 °C were studied. The density was 8.36 g/cm3, and the highest tensile strength and elongation at room temperature reached 1483 MPa and 26%, respectively. At 650 °C, the highest tensile strength and elongation reached 1331 MPa and 28%, respectively. At 650 °C, after 24000 cycles of high cycle fatigue and 100 hours of endurance strength, it did not break. The mechanical properties of FGH4097 superalloys prepared by hot oscillating pressing sintering are comparable to those of “PREP+HIP” technology. The fracture surface of FGH4097 superalloys at room temperature and 650 °C exhibits distinct morphological features of fiber zone, radiation zone, and shear lip zone. The average grain size was 84.7 μm, and approximately 320 nm of γ' phase and (Nb, Ti) C phase were precipitated. The PPBs effect of primary γ' phase and carbide phase at the grain boundaries is suppressed. During the deformation process, dislocation pile up strengthening is formed near the γ' phase and nano carbide phase, while a large amount of stacking faults shear the γ' phase, resulting in the strengthening and toughening of FGH4097 superalloys. This work not only reduce the production cost and short the manufacturing cycle of powder superalloys, but also promote the application of powder superalloys in high temperature field.

Source: Journal of Materials Research and Technology

DOI: 10.1016/j.jmrt.2025.01.197