Interface microstructure evolution and bonding strength of TC11/γ‐TiAl bi‐materials fabricated by laser powder deposition

Abstract

Abstract Laser powder deposition was applied to fabricate the Ti–6.5Al–3.5Mo–1.5Zr–0.3Si (wt%)/Ti–47Al–2Cr–2Nb–0.2W–0.15B (at%) bi‐material system. The as‐deposited TC11 alloy shows a basket‐wave‐like morphology while the as‐deposited γ‐TiAl alloy consists of fully α 2 /γ lamellar microstructures. Regarding the thermal mismatch between TC11 and γ‐TiAl during processing, the interface microstructure evolution was concerned. The transformation pathway was illustrated. It is found that the content changes of Al elements and β‐stabilizers Mo, Cr, and Nb are responsible for the evolution of microstructures at the interface. The fracture surfaces are located at the γ‐TiAl side. The bi‐material shows a brittle‐fracture manner, with the ultimate tensile strength of 560 MPa.