| Abstract Scope |
Ti-48Al-2Cr-2Nb, a lightweight intermetallic alloy with high-temperature strength and oxidation-resistance, suitable for critical aerospace applications, suffers from extreme brittleness and difficulty-for-machining in as-cast condition. Electron-beam-melting, an advanced additive-manufacturing technique although facilitates fabrication of complex component shapes, produces non-uniform microstructures, resulting to property variation. This study systematically investigates the microstructural evolution along with room- and service-temperature mechanical property variation in EBM-fabricated Ti-48Al-2Cr-2Nb alloy, along and perpendicular to the build-orientations in both as-built and HIPed conditions. Microstructure consisting of fine γ and α₂ lamellae are noted to form in as-built condition, while HIPing homogenizes the structure, reduces porosity while coarsening the lamellae. This is reflected in attaining higher hardness for the as-built specimen compared to the HIPed counterpart, as evaluated through small-scale hardness and scratch tests. Bulk-scale tensile, compression and flexure testing at room- and elevated-temperatures indicates comparable strength between as-built and HIPed conditions; however, a pronounced influence of build-orientation is observed. |