Simultaneously enhanced tensile strength and ductility of nano-Y2O3-reinforced TiAl alloy prepared by directed energy deposition

The effect of Y2O3 nanoparticles on microstructure and high-temperature mechanical properties of Ti-48Al-2Cr-2Nb alloy prepared by directed energy deposition was investigated. Cracks in the TiAl alloy sample were eliminated by a new directed energy deposition method with a preheating unit. The results indicated that the microstructure of TiAl alloy without Y2O3 nanoparticles addition was composed primarily of (alpha 2/gamma) lamellar colony. While the equiaxed gamma phase was generated within the (alpha 2/gamma) lamellar colony and on the colony boundaries, and the microstructure exhibited a duplex structure due to the 0.5 wt% nano-Y2O3 addition, and the grain size was decreased from 183 pm to 25 pm. The ultimate tensile strength and fracture elongation tested at 750 degrees C were enhanced simultaneously from 615.1 to 805.7 MPa and from 5.56% to 7.40%, respectively, by 0.5 wt% Y2O3 nanoparticles addition. Finally, the strengthening mechanism and microstructure refinement mechanism were discussed in detail. This investigation provides a valuable reference for TiAl alloy fabrication and widespread engineering applications.

Automated summary

The effect of Y2O3 nanoparticles on the microstructure and high-temperature mechanical properties of Ti-48Al-2Cr-2Nb alloy prepared by directed energy deposition was investigated. The results showed that the addition of Y2O3 nanoparticles improved the microstructure, ultimate tensile strength, and fracture elongation of the TiAl alloy. This study provides important reference for the fabrication and engineering applications of TiAl alloys.