In a significant stride towards enhancing the mechanical properties of additively manufactured alloys, researchers have introduced an innovative approach that could reshape the future of the energy sector. The study, led by Gen Tian from the National Key Laboratory for Remanufacturing in Beijing, focuses on the Inconel 625 (IN625) alloy, a material widely used in harsh environments due to its excellent corrosion resistance and high strength.
The challenge with IN625 alloy, when produced using laser directed energy deposition (LDED), has been the prevalence of large, columnar grains. These grains, a result of complex heat flow during the manufacturing process, lead to low strength and severe anisotropy in mechanical behavior, limiting the alloy’s practical applications. “The columnar grain structure has been a persistent issue, hindering the full potential of IN625 alloy in additive manufacturing,” Tian explains.
To tackle this problem, Tian and his team employed an in-situ hot rolling (ISHR) assisted LDED strategy. The results, published in the journal *Materials & Design* (translated as *Materials and Design*), are promising. The introduction of ISHR during LDED promoted the formation of fine equiaxed grains and increased dislocation density. This led to a doubling of the alloy’s yield strength while maintaining acceptable ductility. Moreover, the anisotropy of tensile properties was improved, addressing a critical limitation of the material.
The enhancement in yield strength is attributed to two main factors: dislocation strengthening and grain refinement strengthening. The related strengthening contributions were calculated to be approximately 240 MPa and 260 MPa, respectively. In-situ electron backscatter diffraction (EBSD) results further revealed that lattice rotation and the formation of low-angle grain boundaries were the primary deformation features of the rolled sample.
The implications of this research are substantial, particularly for the energy sector. IN625 alloy is often used in power generation and oil and gas applications due to its ability to withstand extreme conditions. By improving its mechanical properties, this study paves the way for more robust and reliable components in these industries. “This approach not only enhances the material’s performance but also opens up new possibilities for its use in critical applications,” Tian adds.
The study provides a feasible pathway for removing columnar grain structures and improving mechanical performance in additively manufactured alloys. As the energy sector continues to demand materials that can withstand harsh environments, this research offers a promising solution. The findings could lead to more efficient and durable components, ultimately contributing to safer and more reliable energy infrastructure.
In the broader context, this research highlights the potential of combining traditional manufacturing techniques with advanced additive manufacturing methods. By doing so, it bridges the gap between the two fields and offers a novel approach to material development. As the energy sector evolves, such innovations will be crucial in meeting the demands for high-performance materials.