High temperature tensile properties of directionally solidified Ni-43Ti-4Al-2Nb-2Hf alloy

By liquid metal cooling (LMC) process, the Ni-43Ti-4Al-2Nb-2Hf (%, atomic fraction) alloy was directionally solidified (DS). The microstructure and tensile properties at room and elevated temperature were investigated. It was found that the DS process significantly improves the room temperature tensile strength, increasing by 70% compared with the as-cast alloy. After appropriate heat treatment (HT), the average tensile strength reaches above 1900 MPa, nearly twice of the as-cast one. At 800 and 900 °C, the tensile strengths are about 308 and 169 MPa, respectively.