Phase field simulation of solidification microstructure for Fe-17 wt%Cr model alloy fabricated by laser powder bed fusion Sara Pourmand, Ahmad Kermanpur, Ahmad Rezaeian, Amin Jafari-Ramiani Materials and Design, 2025 • A simulation model developed to predict solidification microstructure in LPBF. • Multiscale model validated against single- and double-track LPBF experiments. • The FVPF model captures heat transfer, melt pool dynamics, and microstructure. • Effects of G, V, and hatch spacing on microstructure morphology investigated. Accurate prediction of solidification microstructures is essential for optimizing laser powder bed fusion (LPBF) process. We present a coupled multiscale framework combining finite volume melt pool simulations with a two-dimensional microscopic phase-field (PF) model. The process-scale model captures transient heat transfer and Marangoni convection, providing local solidification parameters including temperature gradient (G) and growth velocity (V) that directly drive microstructure simulations. Single- and double-track LPBF experiments were conducted on 316L stainless steel under comparable thermal conditions providing model validation. It is shown that increasing laser energy density under conduction mode results in deeper melt pool penetration, enhanced Marangoni convection, cell size enlargement, and more defined cellular structures, collectively promoting melt pool stability and dimensional growth. Results reveal distinct behaviors for successive scan tracks: the second track develops a wider, shallower melt pool due to residual heat and asymmetric boundaries, leading to reduced cooling rates. Simulations capture planar-to-cellular transition and predict primary arm spacings consistent with Hunt and Kurz–Fisher models. Comparison with micrographs confirms that the model reproduces spatial variations in grain morphology and solute segregation. This work demonstrates that a physics-informed CFD–PF coupling, together with a pseudo-binary alloy approximation, enables reliable yet computationally efficient microstructure prediction in LPBF.
Enhanced Poly(Lactic-Co-Glycolic Acid) Composite for Bone Tissue Repair Applications: A Comprehensive Optimization Approach Mahsa Mohammadzadeh, Sheyda Labbaf, Ahmad Kermanpur, Javad Esmaeili Macromolecular Materials and Engineering, 2025 This study explores Poly(lactic‐co‐glycolic acid) (PLGA)‐based scaffolds modified with 10 wt% polycaprolactone (PCL), polylactic acid (PLA), and polyurethane (PU) to enhance their performance. The composite films were characterized by tensile testing, degradability, water absorption, thermal stability, and cell viability. The PLGA/PU group exhibited improved flexibility, while PLGA/PLA showed optimal water absorption (28%) and increased wettability. Contact angle measurements revealed a reduction in hydrophobicity for the PLA (44.4 ± 1 degrees) and PU (43.3 ± 1.6 degrees) groups. Thermal analysis confirmed enhanced thermal resistance for the PLGA/PLA and PLGA/PU composites, making them suitable for applications requiring thermal stability. Additionally, the MTT assay demonstrated over 90% cell viability for the PLGA/PLA group, underscoring its biocompatibility. These findings highlight the potential of PLGA/PLA composites for bone scaffold applications, particularly in additive manufacturing. This study demonstrates that incorporating PLA into PLGA improves key scaffold properties and offers a versatile material for advanced bone tissue engineering.
Investigation of failure mechanism in tensile loading of Cu-AISI4140 steel joints fabricated by spark plasma welding Mehdi Naderi, Mohammad Reza Toroghinejad, Ahmad Kermanpur Journal of Materials Research and Technology, 2025 In this study, failure mechanism under tensile loading of the joint interfaces Cu-AISI4140 steel fabricated by spark plasma welding (SPW) is investigated. The SPW process was conducted at 700 °C and a pressure of 20 MPa for durations of 5, 15, 30, and 60 min. Tensile loading was applied to evaluate mechanical properties of the joints. Microstructural analyses of the joints were performed using scanning electron microscopy, while the fracture surfaces of the samples after tensile testing were examined using field emission scanning electron microscopy. Grazing incidence X-ray diffraction was employed to identify phases at the joint interface on fracture surface of the joints. The results revealed that the SPW process facilitated the forced mixing of Cu in steel and Fe in Cu, without formation of any inter-metallic compound at the joint interface. Additionally, strength of the joint formed over a 60-min duration approached that of Cu. Examination of the fracture surfaces indicated brittle failure in the elastic zone for joints formed over a 5-min duration. As the process time increased to 15 and 30 min, brittle and ductile ruptures occurred, respectively, before reaching the maximum stress in the engineering stress-strain curve. In the joint formed over a 60-min duration, rupture did not occur at the joint interface before reaching the maximum stress in the engineering stress-strain curve. Instead, with the development of micro-necking at numerous areas of the joint interface, ductile failure occurred after reaching the maximum stress.
Effect of niobium on the formation of nano/ultrafine grain structure in a low carbon steel by thermomechanical treatment TMS Annual Meeting, 2013
Effect of Ti on the formation of nano/ultrafine grain structure in the 201L austenitic stainless steel through martensite thermomechanical treatment TMS Annual Meeting, 2013
Application of martensitic transformation fundamentals to select appropriate alloys for grain refining through martensite thermomechanical treatment TMS Annual Meeting, 2013
Synthesis of graphene/CuO magnetic nanocomposite via solvothermal processing TMS Annual Meeting, 2013
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Calculation and experimentation of the compound layer thickness in gas and plasma nitriding of Iron Iranian Journal of Science and Technology Transaction B Engineering, 2010
Microstructural evolution during cold rolling and subsequent annealing in low carbon steel 3rd International Conference on Thermomechanical Processing of Steels Tmp 2008, 2008
