Creep failure analysis of directionally solidified CM247LC superalloy

This study investigates the behavior of an in-house cast directionally solidified nickel-based superalloy (i.e. CM247LC grade alloy) at low and high temperatures (760 and 982 degrees C, respectively). For this purpose, creep and tensile tests were conducted on the alloy after the heat treatment consisted of solutionizing and double aging. Following creep and tensile tests, microstructural examinations were made on the fracture surface and cross-sections of samples by using optical, digital, and electron microscopes. The results showed that the dominant creep mechanism of the CM247LC alloy was dislocation creep at both temperatures. However, the higher temperature accelerated creep failure via de-binding at the matrix/carbide interface and caused severe structural degradation.