Influence of GH4169 addition on cracking control, microstructure and mechanical properties of GH4169/K465 composite material manufactured by selective laser melting

In the process of additive manufacturing, K465 nickel-based superalloy tends to form a eutectic structure with a low melting point. Subsequently, rapid cooling leads to the formation of significant residual tensile stress. This tensile stress makes the prepared sample susceptible to cracking. The research explored the susceptibility to cracking of the alloy material and analyzed the microstructure and properties of GH4169/K465 alloy obtained. The generation of cracks can be managed by decreasing the concentration of Al and Ti elements. The microstructure of GH4169/K465 alloy consists of a matrix phase γ, a white Laves precipitated phase, and spherical particle precipitated phase NbTi4. The mechanical properties of samples 1GH1K, 7GH5K, and 3GH1K were analyzed. The results indicated an elongation exceeding 20 %, a tensile strength exceeding 1000 MPa, and a reduction in hardness from 329 HV to 285 HV. The powder mixing process has been demonstrated to effectively address the shortcomings of individual materials by combining the strengths of different alloy materials to produce a hybrid material with excellent comprehensive performance.