Directed energy deposition of Ni-Al-Cr-C composites: Microstructural evolution during solidification and wear

Laser engineered net shaping (LENS™) allows for the deposition of novel hybrid materials with microstructures composed solid solution and precipitation strengthened metallic matrices, along a distribution reinforcing in situ formed hard ceramic lubricant phases. In this study, four different composites Ni-Al-Cr-C system were fabricated via LENS™ as potential candidate high temperature wear resistant components. Microstructural evolution during solidification sliding studied at room elevated temperatures. Experimental thermodynamic simulations used to evaluate various compositions chromium carbides graphite dispersed into continuous γ/γ′ (L12) matrix. By tailoring build direction, desired hardness properties achieved composites. Specifically, compositional modification carbon determined drastically affect corresponding phase morphology properties. The two lowest rates measured Ni-14Al-9Cr-29 C (at%) composite 500 °C Ni-12Al-3Cr-45 temperature. Mechanistic studies using surface subsurface scanning transmission electron microscopies surfaces revealed was result combination increased hardness/load-bearing formation tribochemical protective oxide glaze layers.