Microstructure and elevated temperature tensile behaviour of directionally solidified nickel based superalloy

In this paper, a nickel based superalloy with good corrosion resistance is fabricated by directional solidification, and its microstructure and tensile properties were investigated. Microstructure observations reveal that besides the ?á? precipitates and ?? matrix, some MC, Ni5Hf and M3B2 particles precipitate along the grain boundary. Tensile tests exhibit that the alloy has obvious anomalous yield and intermediate temperature brittleness (ITB) behaviour. The tensile properties depend on temperature significantly. Below 650??C, the yield strength decreases slightly but rises rapidly between 650 and 750??C, and after then, it decreases gradually with temperature increasing further. Examination by TEM exhibits that sharing of the ?á? by dislocation is almost the main deformation mechanism at low temperature, but the ?á? bypass dominates the deformation at high temperature and the transition temperature should be ~800??C. In addition, the carbides and eutectic structure contribute partly to the ITB behaviours. ? W. S. Maney & Son Ltd. 2013.EISUPPL. 1s101-s1061