Near-Equilibrium Transformation Sequence of NiCrBSi Self-Fluxing Nickel Alloy

NiCrBSi alloys are widely used as wear-resistant deposits. However, despite several studies, there are still some remaining questions concerning their microstructure and the transformation sequence during solidification. This study investigates a gas-atomized powder's non-equilibrium microstructure and a cast sample's near-equilibrium microstructure by synchrotron XRD coupled with SEM observations. NiCrBSi alloys consist of a nickel-rich matrix with CrB, Cr7C3, Ni3B, Ni31Si12 crystals and gamma ' Ni3Si beta 1 precipitates. The transformation sequence is studied by in situ XRD analyses using a synchrotron source. Melting and solidification of Ni31Si12 and Ni3B and solid-state transformations of Ni31Si12 and Ni3Si beta 1 are depicted. Finally, the nickel-rich gamma (Ni) matrix, CrB and Cr7C3, are likely to remain solid at high temperatures up to 1200 degrees C.