In the rapidly evolving world of additive manufacturing, researchers are continually pushing the boundaries of what’s possible, and a recent study led by D. Garcia from the Department of Aerospace and Mechanical Engineering at The University of Texas at El Paso, and the W.M. Keck Center for 3D Innovation, El Paso, TX, USA, has shed new light on the potential of combining different metal alloys using advanced manufacturing techniques. The study, published in ‘Results in Materials’ (translated to English, ‘Results in Materials’), focuses on the microstructural and hardness properties of Inconel 718 claddings deposited onto Inconel 625 substrates using laser powder directed energy deposition (LP-DED) and electron beam powder-bed fusion (EB-PBF).
The research delves into the intricate dance of metals and heat, exploring how different laser power levels and post-process heat treatments affect the final properties of the cladded components. Garcia and his team deposited Inconel 718 claddings onto Inconel 625 substrates using LP-DED at laser power levels of 800, 1000, and 1200 W. The components were then subjected to post-process heat treatments at temperatures of 1025°C, 1175°C, and 1250°C for one hour.
The as-built claddings exhibited a distinctive microstructure consisting of columnar dendrites and precipitate columns, while the heat-treated microstructures showed varying degrees of recrystallization and grains containing {111} fcc annealing twins. “The transition zone in the as-built cladding bond was notably narrow, measuring between 25 and 50 micrometers,” Garcia explained. “However, after heat treatment, the cladding bonds consisted primarily of linked grain boundaries, sometimes alternating between the Inconel 718 alloy cladding and the Inconel 625 substrate.”
The hardness properties of the claddings also underwent significant changes. In the as-built components, the hardness increased from the Inconel 625 substrate to the Inconel 718 cladding. However, after heat treatment, the hardness of the Inconel 718 cladding decreased with increasing heat treatment temperature, ultimately becoming similar to that of the Inconel 625 substrate.
This research has profound implications for the energy sector, where the demand for high-performance, corrosion-resistant materials is ever-increasing. The ability to combine different nickel-based superalloys like Inconel 718 and Inconel 625 using advanced manufacturing techniques opens up new possibilities for creating components with tailored properties. For instance, in the oil and gas industry, components exposed to harsh environments could benefit from the enhanced corrosion resistance and mechanical properties offered by these claddings.
The findings also highlight the importance of post-process heat treatments in optimizing the microstructural and mechanical properties of additively manufactured components. By carefully controlling the heat treatment parameters, manufacturers can tailor the properties of their components to meet specific application requirements.
As the field of additive manufacturing continues to evolve, research like Garcia’s will play a crucial role in shaping future developments. By providing a deeper understanding of the fundamental mechanisms governing the behavior of additively manufactured materials, this work paves the way for the creation of next-generation components with enhanced performance and reliability. The energy sector, in particular, stands to benefit greatly from these advancements, as the demand for high-performance materials continues to grow.