Showing 11 results for Additive Manufacturing
R. Hedayatnejad, H. Sabet, S. Rahmati, A. Salemi Golezani,
Volume 8, Issue 2 (1-2023)
Abstract
This research examines the microstructure and microhardness in the additive manufacturing process using the laser metal deposition method with the deposition of Inconel 718 powder on the Inconel 738 substrate. For this purpose, deposition with different laser power was performed on different substrates, and the microstructure and hardness of the layers were studied. Three layers of Inconel 718 powder were deposited on the substrates. The results show that the laser power parameter in the deposition process significantly affects the microstructure of the samples. By increasing the laser power by 100 W, the distance between the phases γ' in the substrate and γ'' in the layers decreased significantly. With increasing laser power, an increase in the geometric dimensions and volume percentage of the γ'' phase was also observed. In addition, increasing the laser power decreased the volume percentage of the Laves phase. By measuring the microhardness of the deposition layers, it was found that the hardness of the third layer decreases with increasing laser power.
M.r. Maraki, M. Mahmoodi, M. Yousefieh, H. Tagimalek,
Volume 8, Issue 2 (1-2023)
Abstract
In Wire and arc additive manufacturing (WAAM) based on Gas metal arc welding (GMAW) is one of the methods of manufacturing metal layer by layer. One of this method's basic steps is predicting the welding geometry created in each welding step. In the current research, an experimental study was conducted in this field considering the effective parameters of welding geometry. For this purpose, three parameters of voltage, welding speed, and wire feeding speed were considered as effective parameters on the welding geometry of the process. The width and height of the weld bead was selected as the answer according to the type and application of the research. The least squares support vector machine was used to model the welding geometry in the process. The results obtained from the regression (R2) of train, test, validation, and total were 0.945, 0.793, 0.894, and 0.881 respectively. The comparison between the experimental data and the model data shows the significance of the proposed model.
A. Gandomdoust, M. Sarkari Khorrami, S. F. Kashani-Bozorg, H. Ghorbani,
Volume 9, Issue 1 (5-2023)
Abstract
As one of the important pillars of the fourth industrial revolution, metal additive manufacturing (AM) technologies provide a disruptive approach to digital manufacturing. Laser powder bed fusion (LPBF), as one of these technologies, has great potential in producing geometrically complex and high-performance parts. In recent years, the manufacturing of aluminum alloy parts using this technology has attracted much attention. However, their manufacturing still faces some challenging issues. One of the most serious issues encountered in the manufacturing of aluminum alloys, especially high-strength grades, is solidification cracking. In the present investigation, the formation mechanisms of solidification cracking, and the associated effective factors were reviewed. Controlling the solidification microstructure and grain refinement, using the addition of small quantities (<1 wt.%) of micro- or nano-sized particles to the initial alloying powder, was suggested as the most effective method for reducing solidification cracking. These particles act as nucleation sites, prevent grain growth, pin grain boundaries, and with the help of factors that provide constitutional supercooling can effectively minimize solidification cracking. Eventually, effects of various additives in grain refinement and their associated mechanism in reduction of solidification cracks of high-strength aluminum alloys by LPBF is presented.
Vahid Ziaei Laleh, Habib Hamed Zargari, Jamal Sartibi,
Volume 9, Issue 2 (8-2026)
Abstract
Wire and Arc Additive Manufacturing (WAAM) is one of the modern methods of fabrication parts by arc welding under shielding gas. In this research, the thin-wall of austenitic stainless steel 316L was fabricated via WAAM based on inter-pulse current; accordingly, a thin-wall was fabricated in 25-layers using two different strategies with a reciprocating torch movement pattern. Considering the equivalent chromium and nickel content in the Scheffler diagram, it was predicted that the microstructure solidification was done in the austenitic-ferritic (AF) state. Microstructural examination by optical microscopy and X-ray diffraction confirmed the presence of austenite matrix phase alongside ferrite dendrites (about 5%). The tensile test results showed that samples extracted in the vertical direction with an average tensile strength of 454 MPa had about 12% higher strain rates than horizontal samples with a tensile strength of 436 MPa. Also, examination of fine and coarse indentations on the fracture surface of tensile test specimens by scanning electron microscopy showed that the fracture of the specimens was of the ductile type. The hardness of the fabricated thin-wall was measured in the range of 200 to 265 Vickers with an average of 234 Vickers.
Behnam Zamzami, Professor Mehdi Safari, Professor Mohammad Golzar,
Volume 9, Issue 2 (8-2026)
Abstract
Copper coils are essential components of induction hardening machines. The traditional manufacturing process of these coils utilizes extruded copper profiles. In this study, the production of copper profiles using metal 3D printing was experimentally investigated. Two copper samples with hollow square cross-sections, produced by extrusion and metal 3D printing, were evalated for the purpose of manufacturing induction hardening coils. Density, electrical conductivity, hardness, and surface roughness tests were performed in accordance with the relevant standards. The quantitative results for the extruded and 3D-printed samples were, respectively: density of 99% and 93% of the theoretical density of copper; electrical conductivity of 100.8% and 99.1% relative to the annealed copper standard; Brinell hardness of 50 and 59 HB; and surface roughness (Ra) of 0.324-0.533 and 11.949-13.194. The results indicated that the extruded sample possessed higher density, superior electrical conductivity, and a smoother surface, whereas the 3D-printed sample exhibited higher hardness, lower density, and greater surface roughness. These findings demonstrate that metal 3D printing can be utilized for the manufacturing of induction hardening coils.
Mohammadamin Zarei Sahamie, Saeed Shabestari, Hamidreza Abedi,
Volume 9, Issue 2 (8-2026)
Abstract
Wire and Arc Additive Manufacturing (WAAM) has emerged as an efficient technique for producing large-scale austenitic stainless steel components due to its high deposition rate and relatively low cost. However, the steep thermal gradients and repeated thermal cycles inherent to this process may lead to microstructural heterogeneity and anisotropy in mechanical properties.
In the present study, 316L stainless steel walls were fabricated using the WAAM process under controlled primary parameters including welding current, voltage, torch travel speed, and wire feed rate. The solidification behavior, microstructural evolution, and mechanical performance of the WAAM-produced 316L stainless steel were systematically investigated. Microstructural observations revealed that the final structure consists of a γ‑austenitic matrix containing approximately 8.5% δ‑ferrite. Tensile testing demonstrated the simultaneous achievement of high strength and ductility. Specimens extracted perpendicular to the build direction exhibited an ultimate tensile strength of about 569 MPa, a yield strength of 378 MPa, and an elongation of approximately 69%. Mechanical anisotropy was estimated to be around 7.5%, attributed to the directional growth of columnar grains. The enhanced ductility compared to conventional cast steels is associated with the fully austenitic matrix, the controlled amount of δ‑ferrite, the refined dendritic microstructure, and the localized annealing effect resulting from the deposition of successive layers. Microhardness measurements along the build height indicated a gradual decrease in hardness with increasing distance from the substrate, caused by grain coarsening due to heat accumulation and the lower cooling rates in the upper layers. Overall, the findings demonstrate that the WAAM process is capable of producing 316L stainless steel with a balanced combination of high strength and ductility, provided that solidification behavior and thermal history are properly controlled. These results may serve as a basis for microstructure optimization and anisotropy reduction in industrial additive manufacturing applications.
M. R. Maraki, H. Tagimalek, Dr M. Yousefieh, A. Aghaeifar, A. Foorginejad,
Volume 10, Issue 1 (6-2024)
Abstract
Society's great and growing demand for buildings and structures has created the need to apply new construction methods to shorten construction times, make buildings lighter, extend their useful life, and make them more earthquake-proof. In the long term, the new methods will lead to structural optimization, increased building performance, and the achievement of optimal operating conditions. New technologies are meeting society's increasing need for special structures more than ever. Additive manufacturing is based on gas metal arc welding as one of the fastest and most cost-effective manufacturing methods for primary metal structures. For this purpose, the three parameters voltage, wire feed speed, and welding speed were considered initial parameters affecting the width and height of the welding flux. To investigate the effects of the process,
16 experiments with input parameters were evaluated. The width and height of the sweat pollen were determined by experimental investigations. Subsequently, the resulting welding geometry is modeled using three numerical modeling methods, including intensive learning machines, relevence vector machine, and fuzzy logic. The comparison between the experimental data and the results of the three generated models shows that fuzzy logic comes closest to the experimental data of the welding geometry of the modeling methods. For example, the test data of the generative fuzzy model resulted in an average error for height and width of 0.667 and 0.5477, respectively, and a root mean square error for height and width of 0.0046 and 0.3, respectively, which expresses the generalization ability and reliability compared to other modeling methods in this process. Finally, a metal pattern of a special structure was produced based on arc and wire additive manufacturing based gas metal arc welding.
M. K. Vojdanpak, B. Niroumand, M. Shamanian,
Volume 10, Issue 2 (12-2024)
Abstract
Despite rapid advancement of additive manufacturing methods in recent years, sufficient research on bonding of additively manufactured materials to conventional alloys has not been conducted. This study evaluates the bonding between austenitic stainless steel L316 and Ti-6242 alloy, fabricated by electron beam melting, using the transient liquid phase (TLP) bonding method. The TLP bonding was achieved using a copper interlayer and processing in a vacuum furnace, examining the effects of process time and surface roughness on bond quality. The samples were characterized by optical and scanning electron microscopy, X-ray diffraction, shear strength testing, and surface roughness measurement. Results showed that reducing the surface roughness increased the shear strength. Additionally, processing time significantly affected the element diffusion, formation of intermetallic compounds like FeTi and TiCu, and the shear strength of the joints. The highest shear strength of 200 MPa was obtained with surface preparation by grinding and polishing and bonding at 980°C for 120 minutes.
A. Rahimi, M. Yazdizadeh, M. Vatan Ara, M. Pouranvari,
Volume 11, Issue 1 (7-2025)
Abstract
Wire-arc additive manufacturing (WAAM) is a prominent technique for producing large metallic components due to its high deposition rate. Utilizing austenitic stainless steels in this process not only reduces production costs but also provides greater design freedom. Among these steels, SS310, known as heat-resistant steel in the industry, offers excellent oxidation resistance and high-temperature performance. However, it is highly susceptible to hot cracking during welding and additive manufacturing processes. In this study, the microstructure and mechanical properties of SS310 fabricated using WAAM with Cold Metal Transfer (CMT) and Gas Metal Arc Welding (GMAW) processes were compared. The results revealed that the CMT process, due to its lower heat input, effectively reduces the susceptibility of SS310 to hot cracking compared to the GMAW process. These findings emphasize the importance of selecting an appropriate process to achieve high-quality components and minimize structural defects.
M. Ilanlou, R. Shoja Razavi, P. Pirali, M.r. Borhani,
Volume 11, Issue 2 (1-2026)
Abstract
In this study, laser direct deposition was employed to fabricate a functionally graded transition between 17‑4PH stainless steel and Stellite 6. Specimens were designed and produced such that the chemical composition varied incrementally from 100% 17‑4PH to 100% Stellite 6, with each step involving a 25% decrease in the 17‑4PH content and a corresponding 25 % increase in Stellite 6. Microstructural evolution and elemental distribution were characterized by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), while mechanical properties were assessed via Vickers microhardness testing and uniaxial tensile tests. The microstructural analysis revealed a needle‑like martensitic matrix in the substrate, which transformed into cellular dendrites upon reaching the 25% Stellite 6 layer. As the Stellite 6 fraction increased, along with corresponding rises in Cr and W content, grain boundaries broadened and carbides accumulated within interdendritic regions. At the 50% composition, oriented columnar dendrites became prominent, and at higher Stellite 6 levels the dendritic structure refined further, ultimately evolving into an equiaxed morphology. Microhardness measurements showed a continuous increase from approximately 300 HV in the 17‑4PH substrate to 490 HV in the pure Stellite 6 layer. Tensile testing demonstrated that both yield strength (σᵧ) and ultimate tensile strength (σᵤ) remained within 1102–1159 MPa across all compositions, with no evidence of brittle phases or manufacturing defects. Elongation increased from 7% in pure Stellite 6 to 19% in pure 17‑4PH, with the 50%–50% gradient exhibiting an optimal balance of strength and ductility (14.5% elongation).
M. H. Saebi, A. H. Emami Ghalehghasemi, M. Atapour, A. Saboori,
Volume 11, Issue 2 (1-2026)
Abstract
The Ti-6242 alloy is of particular significance in additive manufacturing due to its high thermal resistance. However, components fabricated from this alloy using the electron beam powder bed fusion (EB-PBF) process often exhibit poor surface quality, primarily resulting from the layer-by-layer fabrication nature and and the presence of partially melted powder particles. In this study, laser polishing was employed to enhance the surface characteristics of EB-PBF fabricated Ti-6242 specimens using three laser powers (195, 260, and 325 W) and two scanning speeds (4.5 and 3 mm/s). The effects of these parameters on surface roughness, microstructure, and mechanical properties were evaluated through surface profilometry, metallography, hardness, and wear tests. The results indicated that the average surface roughness decreased by up to 93%, from 9.36 µm to 0.61 µm. Moreover, the initial α and β phases transformed into a fine, martensitic α′ phase within the polished layer, leading to a 33% increase in hardness—from 380 to 506 HV—and a significant improvement in wear resistance. Consequently, optimal adjustment of laser polishing parameters can simultaneously reduce surface roughness and enhance the mechanical performance of Ti-6242 components.
