Mechanical Properties Response of Isotropic Ti2alnb/Tial Interpenetrating Phase Composites with Tpms Architectures Prepared by Laser Powder Bed Fusion

Abstract

TiAl alloys with high specific strength, excellent oxidation resistance and high-temperature performance are considered to replace nickel-based superalloys in the range of 700-800 °C. However, the low fracture toughness is still the biggest bottleneck restricting their development. Moreover, the anisotropy of continuous fibers and laminated structures reinforced composites is still present. In this study, a three-dimensional continuous Ti2AlNb scaffold suitable for the strengthening and toughening of the TiAl alloys was designed. Furthermore, the forming quality of the scaffolds prepared by L-PBF was studied, and the anisotropy of L-PBF printed scaffolds was evaluated through the homogenization method and finite element simulation (FEA). What’s more, the IPCs were prepared by HPS. And the deformation-failure behaviors of scaffolds and their IPCs were analyzed by experimental and FE-simulated quasi-static compression tests. The results show that the L-PBF formability of TPMS structures is better than that of Cross-lamellar structures, and the equivalent diameter and number of pores for the TPMS structures are small, mostly distributed in 30-60 µm with the volume fractions (VFs) of 0.14%-0.26%. The Gsh and SPsh structures exhibit excellent isotropy, followed by the Dsh structure, while the Gsk and Psh structures show obvious anisotropy as the VF changes. The deviation between the maximum and minimum compressive strength values ranges from 1.7% to 9.3% for IPCs with a VF of 30%, indicating that IPCs show good isotropy. The elastic modulus and yield strength of Gsh-IPCs are 15.8% and 8.2% higher than that of linear addition of TiAl matrix and Gsh scaffolds, respectively.

Keywords: Ti2AlNb/TiAl, Interpenetrating phase composites, TPMS architectures, Laser powder bed fusion, Mechanical properties response