Shiraz UniversityIranian Journal of Materials Forming2383-004212320250701Iranian Journal of Materials Forming, Issue 3, July 202523824310.22099/ijmf.2025.8243ENRaminEbrahimiDepartment of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz, IranJournal Article20250916The “<strong>Iranian Journal of Materials Forming (IJMF)</strong>” is an international open-access journal dedicated to materials deformation and forming processes, established at Shiraz University in 2014. The journal welcomes submissions from scientists and engineers in both academic and industrial fields related to all manufacturing processes. Its scope includes all types of deformation, encompassing elastic and plastic behavior as well as deformation due to failure.<br />The journal’s quality and credibility are upheld by an editorial board comprising some of the world’s most renowned professors. Additionally, the diverse and distinguished panel of referees featured in this issue reflects its high scientific standards.<br />We take pride in consistently publishing quarterly issues, now marking our fifth successful year, with the third issue of 2025 recently released.https://ijmf.shirazu.ac.ir/article_8243_46b0c5c4b701e206dc7d93a5d5d0a4e0.pdfShiraz UniversityIranian Journal of Materials Forming2383-004212320250701Predicting Maximum Process Temperature in Cortical Bone Milling: An XGBoost Approach with Sensitivity Insights419818610.22099/ijmf.2025.52838.1330ENVahidTahmasbiDepartment of Mechanical Engineering, Arak University of Technology, Arak, IranMahdiQasemiDepartment of Mechanical Engineering, Arak University of Technology, Arak, IranAmir HosseinRabieeDepartment of Mechanical Engineering, Arak University of Technology, Arak, IranJournal Article20250330Bone milling, a crucial biomechanical process in medical engineering, finds applications in dentistry, orthopedic surgery, and bone-related treatments. The utilization of computer numerical control (CNC) surgical mills has significantly enhanced this process, but it comes with challenges such as elevated temperatures that induce thermal necrosis in bone tissue. This study examines key inputs, including tool diameter, feed rate, rotational speed, and cutting depth, conducting a detailed experiment to predict maximum process temperature using the XGBoost machine learning algorithm. The XGBoost model consistently demonstrated exceptional predictive accuracy, yielding high determination coefficients of 0.99 in training and 0.94 in testing. Accurate predictions were evident through close alignment between model-predicted and actual values, with mean absolute percentage error (MAPE) values of 0.33% and 3.38% for training and testing, respectively. Rotational speed emerged as a critical factor, indicating a key point where temperature trends shift. Higher speeds are correlated with lower temperatures due to enhanced chip removal and reduced bone heat conductivity. Elevated feed rates were associated with increased bone temperature, emphasizing the intricate interplay between frictional forces and heat production. Additionally, often-overlooked factors like cutting depth and tool diameter substantially influenced process temperature, impacting surgery recovery times. Sobol sensitivity analysis identified cutting depth, rotational speed, tool diameter, and feed rate as primary factors influencing maximum process temperature fluctuations, with effectiveness percentages of 46.7%, 36%, 13.2%, and 4.1%, respectively. This comprehensive analysis sheds light on optimizing bone milling processes and mitigating thermal risks in medical applications.https://ijmf.shirazu.ac.ir/article_8186_27ef9bdc9bdf2a4a796de24fba7145cd.pdfShiraz UniversityIranian Journal of Materials Forming2383-004212320250701Ring Expansion with a Stepped Conical Punch to Extract the Workability Diagram in Bulk Metal Forming for C22000 Alloy: Experiments and Numerical Simulation with Ductile Damage Model2032819910.22099/ijmf.2025.52038.1314ENSeyyed MohsenSeyyed HatamiFaculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, IranHoseinLexianFaculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, IranMehrdadKhandaeiFaculty of Material and Manufacturing Technologies, Malek Ashtar University of Technology, IranJournal Article20241228Workability is a measure of the extent of deformation that a material can withstand before failure in bulk forming processes. In these processes, ductile fracture is the most common failure mode. In this study, ring expansion tests with a stepped conical punch were performed on samples with different geometries. For each strain path, axial and circumferential strains were calculated, and the right side of workability diagram was extracted. The primary objective of this paper is to determine the workability of C22000 alloy by fracture in mode I of fracture mechanics, which involves crack opening by tension. This study is the first, to the authors' knowledge, to simultaneously determine the right side of the workability diagram using anisotropic ductile damage mechanics. The formulation was developed within the framework of thermodynamics of irreversible processes, and a symmetric second-order tensor was used to describe the anisotropic damage state variable. The model was implemented using VUMAT coding and ABAQUS/Explicit software to simulate experimental tests. In order to display the workability diagram numerically, the adopted approach is based on the determination of damage values. Previous strain measurements were made just before crack initiation, and thus, with this method, the extraction of the diagram is done more comprehensively. The results show that different levels of damage and damage evolution can represent distinct regions of the workability diagram.https://ijmf.shirazu.ac.ir/article_8199_615ffb395fafc897bd4da6c00e877e96.pdfShiraz UniversityIranian Journal of Materials Forming2383-004212320250701Accelerated Homogenization of a Cast Nickel-Based Superalloy VDM780 via Thermomechanical Processing3341821810.22099/ijmf.2025.53481.1334ENHoomanChavilianSchool of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, IranSeyed HosseinRazaviSchool of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, IranBagherMohammad SadeghiSchool of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, IranHamid RezaAbediSchool of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, IranSeyed MahdiAbbasiSchool of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, IranJournal Article20250610In recent years, the push to reduce fuel consumption and emissions in turbines, designs have focused on achieving higher operating temperatures, which require materials capable of sustaining elevated temperatures in industrial applications. The development and production of the nickel-base superalloy VDM780, with an operating temperature above 750 °C (nominally 780 °C), have been pursued to meet this demand. This superalloy is often considered a suitable alternative to Inconel 718. The present study demonstrates the thermomechanical processing can significantly accelerate homogenization, enabling the production of a wrought structure in VDM780 with minimal heat treatment. A cast ingot of the VDM780 superalloy was first prepared using a vacuum induction melting (VIM) furnace, without employing refining processes such as electroslag remelting (ESR) or vacuum arc remelting (VAR). The conditions for homogenization and hot rolling were then investigated using simultaneous thermal analysis (STA). The results show that a homogenization temperature of 1160 °C provides adequate homogenization, resulting in a microstructure that is well-suited for workability.https://ijmf.shirazu.ac.ir/article_8218_b83185b1608585fa771012c1adedfe1d.pdfShiraz UniversityIranian Journal of Materials Forming2383-004212320250701Micromechanical Modeling of Two-Way Shape Memory Response of Semi-Crystalline Polymers Based on Equivalent Inclusion Method4255823910.22099/ijmf.2025.53516.1335ENMeisamBakhtiariDepartment of Materials Science and Engineering, K. N. Toosi University and Technology, Tehran, IranKeivanNarooeiDepartment of Materials Science and Engineering, K. N. Toosi University and Technology, Tehran, IranJournal Article20250616Two-way shape memory polymers (2W-SMPs) are a class of intelligent materials that demonstrate reversible form memory, rendering them suitable for a wide range of applications in response to external stimuli. During the phase transition in the shape memory cycle of semi-crystalline polymers, the 2W-SMPs are represented as a two-phase material, consisting of an amorphous matrix and the crystalline inclusions. This paper employs the Equivalent Inclusion Method (EIM), based on the Modified-Mori-Tanaka (MMT) approach, to determine the effective thermomechanical response of inclusions inside a heterogeneous matrix. Unlike existing phase transition models, the proposed model accounts for both phase interactions and the morphology (shape and size) of the inclusion phase throughout the thermomechanical cycle. The model was implemented using the UMAT user subroutine in ABAQUS to simulate the mechanical behavior of SMPs. Analysis of various inclusion shapes revealed that ellipsoidal shapes most accurately represent the morphology of the inclusion phase. In particular, a highly elongated ellipsoidal inclusion (a/c = 1/25) provided the best agreement with simulation results. A fivefold increase in the (a/c) aspect ratio of the crystalline inclusions resulted in approximately 10% increase in crystallization-induced strain, thereby improving consistency with shape memory experiments when the actual morphology was considered. The shape memory response of PCL under a stress of 250 kPa demonstrated a ~12.5% strain increase during cooling from 65 to -40 ̊C, with about 7% occurring near the crystallization point over a 40 ̊C interval. Incorporating phase interactions significantly enhanced the model's agreement with experimental results on shape recovery.https://ijmf.shirazu.ac.ir/article_8239_0ec2040c98e90c15246bb07603ee9e03.pdfShiraz UniversityIranian Journal of Materials Forming2383-004212320250701Activation Energy and Zener-Hollomon Mapping of Hot-Deformed API X80 Steel Using Modified Hyperbolic Sine Constitutive Models5668825210.22099/ijmf.2025.53717.1336ENHamedEskandariDepartment of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, IranMohsenReihanianDepartment of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, IranSeyed RezaAlavi ZareeDepartment of Materials Science and Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, IranJournal Article20250720This study investigates the hot deformation behavior of API X80 pipeline steel using modified hyperbolic sine-based constitutive models. Uniaxial compression tests were conducted at temperatures of 950 to 1100 °C and strain rates of 0.001 to 1 s⁻¹. Five constitutive approaches were evaluated: linear-linear Shi (LLS), linear-polynomial Shi (LPS), polynomial-polynomial Shi (PPS), and polynomial-polynomial Yang (PPY). Results indicate that activation energy (Q) varies significantly with deformation conditions. While the constant Q (CAE) model provides reasonable predictive accuracy and remains useful for simplified analysis, the PPY model demonstrates superior performance by capturing complex dependencies between stress, temperature, and strain rate. Zener-Hollomon (Z) maps and Q contours further illustrate the impact of model selection on process prediction. These findings establish a reliable computational framework for accurately modeling and optimizing hot deformation in high-strength steels.https://ijmf.shirazu.ac.ir/article_8252_4b2c885e23be83e53ac8a0b115c0478f.pdfShiraz UniversityIranian Journal of Materials Forming2383-004212320250701Development of a Modified Relationship Between the Constant Friction Factor and the Coefficient of Friction in Extrusion Using Upper Bound Analysis6973828210.22099/ijmf.2025.53940.1342ENMohammad BagherLimooeiDepartment of Materials Engineering, Am.C., Islamic Azad University, Amol, IranJournal Article20250809This study evaluates friction in bulk metal forming processes, where frictional shear stress is commonly described by either Coulomb’s friction law or the constant friction factor law. Despite their widespread use, establishing a precise correlation between the constant friction factor (m) and the coefficient of friction (μ) remains challenging. Building on previous work, a modified relationship between these parameters is proposed to improve consistency across practical friction ranges. The new equation is based on upper bound analysis, incorporating both the constant friction factor and Coulomb’s hypothesis. Using regression on the extrusion process results, the equation was obtained and validated. The proposed equation satisfies the required boundary conditions and offers simplified implementation in forming simulations. Comparative analysis shows strong agreement, particularly under low-friction conditions typical of metal forming. The findings enhance the reliability of frictional behavior modeling in engineering applications.https://ijmf.shirazu.ac.ir/article_8282_4e81fd23dadc1ace6b02f8bb58c40cdd.pdf