The directionally solidified Ni-based superalloy, which is composed of columnar crystals, shows excellent comprehensive properties [1,2] . Thus, it can be used for blade materials for industrial gas turbines (IGTs) [3,4] . In recent decades, with the increase of turbine inlet temperature, the temperature bearing capacity of turbine blades faces a huge challenge [5] . It is of critical importance to improve the high temperature strength of directionally solidified columnar Ni-based superalloy. According to the development experience of aero-engine blades, optimizing the microstructure of alloys by adding refractory elements (Mo, W, Re, Ta) would be effective in improving the hightemperature strength of alloys for IGTs [6][7][8] .

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