Reza Ghanavati

Bridging process, microstructure, and fatigue behavior in L-PBF Ti-6Al-4V: a critical review

Roadmap on Artificial Intelligence‐Augmented Additive Manufacturing

Artificial intelligence‐augmented additive manufacturing (AI2AM) represents a transformative frontier in digital fabrication, where artificial intelligence (AI) is embedded not as a peripheral tool, but as a central framework driving intelligent, adaptive, and autonomous additive manufacturing (AM) systems. The objective of this Roadmap is to present a comprehensive vision of the state‐of‐the‐art developments in AI2AM while charting the future trajectory of this rapidly emerging field. As AM applications continue to expand across diverse sectors, conventional design and control strategies face growing limitations in scalability, quality assurance, and material complexity. AI uses tools like computer vision, generative design, and large language models to help solve problems in scalability, quality assurance, and material complexity, allowing for real‐time defect detection, digital twin integration, and closed‐loop process control. This roadmap brings together leading contributions from twenty internationally recognized research groups by uniting perspectives from materials science, computer science, robotics, and manufacturing. This work aims to create a cohesive framework for advancing AI2AM as a multidisciplinary science. The ultimate intent of this work is to establish a foundation for coordinated research and innovation in AI‐powered AM and to serve as a strategic entry point for future breakthroughs in autonomous and sustainable production.

GhanavatiMaterials Characterization

Design optimization for defect-free AISI 316 L/IN718 functionally graded materials produced by laser additive manufacturing

Additive manufacturing (AM) of functionally graded materials (FGM) has become an important growing trend in the research and development of various sectors. The main challenging issue is alloy design for the transition zone between terminal alloys so that the expected performance is achieved with minimal risk of defects. In this study, the transition zone design in AISI 316 L-IN718 FGM via laser-directed energy deposition (L-DED) is investigated concerning susceptibility to cracking defect, its formation mechanisms, as well as the design effect on mechanical properties. Consequently, the compatible design of the AISI 316 L-IN718 graded materials is established for laser-based AM. The evaluation of the gradient structures showed that the 75 % AISI 316 L-25 % IN718 region, with the continuous evolution of low-melting eutectic compounds caused by the formation of crystallographic texture in the build direction, is highly sensitive to liquation cracking, which occurs in the presence of thermal stresses arising from the deposition of subsequent layers. In addition, defects of porosity and oxide micro-inclusions intensify the discontinuity and cracking in the remarked composition region. Finally, it was demonstrated that the improvement of the dissimilar structure of AISI 316 L and IN718 alloys can be purposefully fulfilled by designing a compositional gradient in the form of a 50 wt% mixed region between the base alloys (FGM-50 %) resulted in the maximum mechanical properties (tensile strength 540 ± 10 MPa, elongation 52 ± 2 %, and toughness 24 ± 1.4 kJ/mm 3 ). • Fabrication of different designs of SS316L-IN718 FGM by L-DED has been studied. • 75 % SS316L-25 % IN718 region of FGM-25 % exhibited a high susceptibility to cracking. • The mechanism of cracking in SS316L-IN718 FGM by L-DED has been discussed. • Mechanical properties of SS316L-IN718 FGM by L-DED has been analyzed. • Concentration of interfacial residual stresses in the FGM-50 % improves the performance.

The impact of heat treatment on microstructure, residual stress, and mechanical behavior of laser powder bed fusion additively manufactured Ti–6Al–2Sn–4Zr–2Mo alloy

In the field of additive manufacturing (AM), a promising alloy that is gaining attention is the near-α Ti–6Al–2Sn–4Zr–2Mo (Ti6242) alloy. This alloy is known for its remarkable resistance to creep and corrosion at elevated temperatures. However, the production of Ti6242 components via Laser-based AM technologies faced with several challenges, such as the formation of residual stress in the as-built state that originates from the nature of these processes. Therefore, this study has a dual objective: first, to evaluate the microstructure and residual stresses in the as-built Ti6242 produced through laser powder bed fusion. Secondly, to investigate the impact of a promising post heat treatment on mitigating residual stresses, inducing alterations in the microhardness of the Ti6242 alloy and its ductility, phase transformations and microstructure evolution. The as-built specimen exhibited a significant residual stress of 1357 MPa, which was caused by the pronounced temperature gradients experienced during the fabrication process. It is interesting to note that this promising post heat treatment was highly effective in eliminating 99% of the residual stress. After heat treatment, the amount of α′ present in the as-built specimen decreased. This resulted in the activation of diffusion of elements such as molybdenum, causing a proportion of the α′ to decompose into the more ductile α+β structure. Additionally, it is revealed that the microstructural changes and relieved stresses from the heat treatment process caused a lower microhardness and a higher ductility under compressive loading, as the elongation and toughness reached 20.5% and 23.255 kJ/mm 3 in the heat-treated samples, respectively. The outcomes of this work facilitate the use of this alloy in the production of complex shape components through laser-based AM technologies.

Untapped Opportunities in Additive Manufacturing with Metals: From New and Graded Materials to Post-Processing

Metal additive manufacturing (AM) is an innovative manufacturing method with numerous metallurgical benefits, including fine and hierarchical microstructures and enhanced mechanical properties, thanks to the utilization of a local heat source and the rapid solidification nature of the process. High levels of productivity, together with the ability to produce complex geometries and large components, have added to the versatile applicability of metal AM with applications already implemented in various sectors such as medicine, transportation, and aerospace. To further enhance the potential benefits of AM in the context of small- to medium-scale bulk production, metallurgical complexities should be determined and investigated. Hence, this review paper focuses on three significant metallurgical aspects of metal AM processes: in situ alloying, functionally graded materials, and surface treatments for AM parts. The current text is expected to offer insights for future research works on metal AM to expand its potential applications in various advanced manufacturing sectors.

GhanavatiSHILAP Revista de lepidopterología

Printability and microstructure of directed energy deposited SS316l-IN718 multi-material: numerical modeling and experimental analysis

In the present paper, the interrelated aspects of additive manufacturing-microstructure-property in directed energy deposition of SS316L-IN718 multi-material were studied through numerical modeling and experimental evaluation. The printability concept and solidification principles were used for this purpose. The printability analysis showed that the SS316L section is more susceptible to composition change and lack of fusion, respectively due to the high equilibrium vapor pressure of manganese and the more efficient heat loss in the initial layers. However, the IN718 section is more prone to distortion due to the formation of a larger melt pool, with a maximum thermal strain of 3.95 × 10⁻³ in the last layer. As the process continues, due to heat accumulation and extension of the melt pool, the cooling rate decreases and the undercooling level increases, which respectively result in coarser microstructure and more instability of solidification front in the build direction, as also observed in the experimental results. The difference is that the dendritic microstructure of the IN718 section, due to the eutectic reaction L → γ + Laves, is formed on a smaller scale compared to the cellular microstructure of the SS316L section. Also, the decrease in cooling rate caused the secondary phase fraction in each section (delta ferrite in SS316L and Laves in IN718) to increase almost linearly. However, the hardness calculation and measurement showed similarly, even though with the transition from SS316L to IN718 the hardness is significantly increased due to higher yield strength of the matrix and the presence of Laves intermetallic phase (~ 260 HV0.3), the hardness in each section decreases slightly due to the coarsening of the microstructure from the initial layer to the final.

GhanavatiJournal of Materials Research and Technology

Additive manufacturing of thin-walled SS316L-IN718 functionally graded materials by direct laser metal deposition

GhanavatiSHILAP Revista de lepidopterología

Additive manufacturing of functionally graded metallic materials: A review of experimental and numerical studies