Microstructure and mechanical properties of TC11-TiAl three-dimensional heterogeneous material fabricated by laser directed energy deposition

Titanium aluminide (TiAl) alloys exhibit excellent high-temperature performance, making them promising candidates for aerospace applications. However, their mechanical properties still require further enhancement. In this study, a TC11-TiAl three-dimensional heterogeneous material (THM) was fabricated via laser directed energy deposition to improve mechanical properties. Results showed that the microstructure of THM consists of coarse columnar grains, which were parallel to the build direction with internal basketweave structure and α₂ + β/B2 phases. Based on elemental distribution, the THM was divided into TiAl-rich and TiAl-lean regions. In the TiAl-rich region, a higher α₂ phase fraction than TiAl-lean region was found. Compared to pure as-deposited TiAl alloy, the THM exhibited significantly improved ultimate tensile strength (UTS) of 713 ± 60 MPa and a similar elongation (EL) of 0.6 ± 0.1 % at room temperature. The THM also demonstrated a good high-temperature property, achieving a UTS of 642 ± 45 MPa and 1.8 ± 0.7 % EL at 650 °C.