Microstructures and mechanical properties of GTD222 superalloy fabricated by selective laser melting

Selective laser melting (SLM) has drawn increasing attention because of its high degree of flexibility for the design and fabrication of geometrically complex parts. GTD222 is a cast superalloy that is currently used in the energy and aviation fields. SLM of GTD222 is a potential manufacturing method for gas turbine blades or complex parts of aero-engines. In this study, the effect of processing parameters on the metallurgical defects and density of SLM processed (SLMed) GTD222 were studied, and the optimal SLM processing parameters for GTD222 were obtained. Then, SLMed GTD222 samples were prepared based on the optimal SLM processing parameters, and the microstructures and mechanical properties of SLMed GTD222 samples were investigated. The results indicated that the mechanical properties of SLMed GTD222 were obviously improved compared to those of cast GTD222, especially with respect to elongation. The superior mechanical properties were attributed to the amelioration of porosities and micro-segregation, the refined microstructure and the abundant dislocations at sub-crystal boundaries.