International Journal of Material Forming最新文献

The production of aluminium strip involves a long sequence of thermomechanical processing steps that significantly influence the material’s mechanical properties and may induce anisotropy. This anisotropy can manifest as earing during deep drawing operations - such as those used in beverage can manufacturing - resulting in increased trimming scrap, process downtimes, and reduced economic viability. To assess formability and quantify earing, the cup drawing test is employed as a standard evaluation method. Understanding and minimizing earing formation requires comprehensive modelling of the entire process chain, which is traditionally performed manually by domain experts - a time-consuming, error-prone, and costly effort. This study presents a novel, scalable, and flexible approach to model a process chain by integrating production data with process models on the Microsoft Azure Databricks platform. The proposed method is validated on an industrial aluminium strip production line, demonstrating its capability to automate data processing, extract actionable insights, and support process optimisation. The approach successfully identifies an optimum processing route that minimises the earing integral, as determined by a dedicated evaluation function.

This paper studied the effect of energy density on the formability of the selective laser melting (SLM) 6063 aluminum alloy, and analyzed the density, surface quality, microstructure and mechanical property. In the SLM 6063 aluminum alloy, there were mainly two kinds of pore defects, i.e. non-fusion and pores. When the energy density was low (< 100 J/mm³), serious solidification crack defects existed in the specimen. With the increase of energy density, the crack defects in the specimen gradually improved. At the same time, the density generally showed a trend of first increasing and then decreasing. The energy density range of 66.67 ~ 100 J/mm³ was more conducive to the forming of high-density specimens (> 97%). The microhardness of the SLM 6063 aluminum alloy in each group was about 40 HV, which was less affected by process parameters. When the scanning speed was constant, with the increase of laser power, the tensile strength of the specimen first increased and then decreased, and the elongation first decreased and then increased. When the laser power was constant, the tensile strength of the specimen decreased sharply with the increase of scanning speed, and the elongation increased first and then decreased. Considering the density, crack defects and mechanical properties of the specimens under different process parameters, the laser power of 360 W, the scanning speed of 1000 mm/s, and the scanning spacing of 0.1 mm were identified as optimal process parameters, which can be used as a theoretical reference for the preparation of high-quality SLM aluminum alloy.

Aluminum alloy sheets are widely used in lightweight industries due to their excellent performance, but the springback defects in complex forming processes are difficult to predict and control precisely. In this paper, S600 high-strength aluminum was taken as the target. A method combining theoretical analysis, finite element simulation, and forming-process tests was adopted to develop the model. The multi-objective improved non-dominated sorting genetic algorithm was used to optimize the anisotropic yield criterion parameters of Yld2000-2D anisotropic yield criterion. Subsequently, a hybrid calibration strategy combining the multi-objective optimization algorithm and the inverse solution method was adopted to collaboratively optimize the parameters of the Chaboche hybrid strengthening model. And the springback simulation and forming test were conducted to verify the accuracy of springback prediction of the established constitutive models. For two-dimensional cylindrical surface and three-dimensional space complex surface, the maximum prediction deviations of the Yld2000-2D-Chaboche model have increased 24.3% and 12.7% respectively. For different stamping amounts (20 mm and 30 mm) of the C-shaped beam, the average errors were 0.2 mm and 0.06 mm respectively. This series of comparative verifications not only confirmed the accuracy of the optimized Yld2000-2D-Chaboche model, but also fully proved its wide applicability in complex forming processes.

Although extensive studies have been conducted to predict ductile fracture at room temperature, no attempt has been made to use Gurson–Tvergaard–Needleman (GTN) model to capture the effect of temperature due to spindle speed induced friction heat on damage accumulation in incremental sheet forming (ISF). In this work, the temperature effect is incorporated into a shear modified GTN model to characterise ductile fracture behaviour of an aluminium alloy (AA1050) at varying temperatures in ISF processing under different strain states. The correlation between void evolution and damage accumulation at different temperatures is revealed, and the void volume fraction (VVF) at different deformation stages is determined by conducting microscopic in-situ tensile test. By introducing a new temperature-dependent VVF function and determining appropriate GTN damage parameters, ductile fracture under different ISF processing temperatures is evaluated using FE simulation and validated by ISF experimental testing. The results show that the proposed temperature-dependent VVF function in GTN modelling is capable of predicting the ductile fracture of both the set temperatures in in-situ tensile tests and the varying temperature conditions in ISF processes. This study unveils the underlying mechanisms behind material deformation and damage evolution with consideration of temperature variations caused by tool spindle speed at various ISF forming conditions, which provides guidance for process optimisation and formability improvement in ISF process.

Variable wall-thickness tubes are increasingly required for lightweight, functionally optimized structures and heat-transfer components, yet conventional hollow sinking with a constant speed ratio between the feeding and drawing sides produces an almost uniform wall thickness along the tube axis and cannot generate a taper. This study proposes a simple hollow sinking process for fabricating variable wall-thickness microtubes without an inner tool by controlling the speed ratio between the feeding and drawing sides, that is, by increasing the drawing speed during processing while keeping the feeding speed at the die entrance constant. Austenitic stainless-steel (SUS304) tubes with an outer diameter of 2.0 mm, an inner diameter of 1.82 mm, and an initial wall thickness of 0.09 mm were drawn under these conditions, where the drawing speed on the exit side was continuously increased while the feeding speed was fixed. The resulting wall-thickness distributions and surface roughness were evaluated experimentally and by finite-element analysis, which consistently showed that the increasing speed ratio enhances the axial elongation per unit time beneath and just after the die, thereby geometrically introducing a taper slope on the inner wall. Using this method, tubes with a maximum wall-thickness difference of about 40% between thick and thin sections were fabricated while maintaining acceptable outer and inner surface quality. These results demonstrate that variable-thickness microtubes can be intentionally produced in hollow sinking through simple control of the speed ratio between the feeding and drawing sides, extending the conventional geometric framework for straight tubes to tapered tubes.

Zn-based alloys have attracted significant attention as potential candidates for biodegradable implants due to their excellent biocompatibility; however, their inherently low tribological performance continues to restrict practical applications. In the present study, a Zn1AgCuMg alloy was fabricated via induction melting–casting and subsequently processed through cold extrusion and equal channel angular pressing (ECAP) using various routes (A, C, R, Bc) and pass numbers (1–4). The processing resulted in substantial microstructural refinement, reducing the average grain size from 245 μm in the as-cast condition to 72 μm after ECAP Route-Bc with four passes, accompanied by an increase in hardness from 62 HV to 113 HV. The yield strength improved from 150 MPa (as-cast) to 164 MPa after extrusion, and further to 217 MPa following ECAP Route-Bc (four passes). Similarly, the corrosion rate decreased from 294 mpy in the untreated alloy to 232 mpy after extrusion and to 66.16 mpy after ECAP Route-Bc (four passes). Tribological assessment revealed negligible differences between extrusion and 1–2 pass ECAP samples; however, a marked enhancement in wear resistance was observed in the 3–4 pass ECAP conditions, with the lowest friction coefficient (0.083) achieved for ECAP Route-Bc (four passes). These results confirm that controlled severe plastic deformation via ECAP can concurrently improve mechanical strength, wear resistance, and corrosion resistance in Zn-based biodegradable alloys, with multi-pass ECAP Route-Bc offering the most balanced performance for prospective implant applications.

Incremental Sheet Forming (ISF) is a flexible, dieless manufacturing process that enables rapid prototyping and small-batch production of complex geometries without the need for dedicated tooling. A key aspect of ISF process optimization is the accurate measurement of formability, traditionally achieved through electrochemical etching (EE) of circle grids. However, EE is time-consuming, requires specialized dies, and can yield inconsistent results. This study explores laser marking as an alternative technique for formability evaluation in ISF, comparing its performance with conventional EE. Aluminum alloy (AA1200-H14) sheets were marked using both CO₂ and Nd: YAG nanosecond-pulsed lasers under various process parameters, and the resulting surfaces were analyzed in terms of groove depth, contrast, and marking reproducibility. Incremental forming tests were conducted using a robotic arm to assess the influence of marking methods on material behavior and formability. Statistical analyses revealed that the Nd: YAG laser with parameter set 1 achieved optimal results, producing high-contrast, geometrically precise, and reproducible grids without adversely affecting the mechanical integrity of the material. Conversely, excessive energy input parameter set 2 significantly reduced formability due to surface damage and stress concentration. The findings demonstrate that properly optimized laser marking provides a reliable, non-contact, and efficient method for strain measurement in ISF, overcoming the limitations of electrochemical etching and supporting improved process monitoring and prediction.

The application breadth and strategic value of magnesium alloy bending parts, which offer significant lightweight advantages within the manufacturing field, continue to increase. However, forming defects such as cracking and springback that are generated during the bending process, along with the problem of accurate statistics of dynamic response data of overall macro and micro characteristics, seriously restrict the improvement of bending performance and hinder its application toward lightweight and depth. The three key strategies based on microstructure dominance, process path dominance, and numerical simulation dominance have become the core means to improve the bending performance due to the significant effectiveness of their control effects. This paper systematically reviews the latest progress in the regulation of bending properties of magnesium alloys, with a focus on the diversified design of microstructure, multifaceted innovation of process path, and numerical simulation of bending properties. Furthermore, challenges and future development directions of the research are prospected, in order to provide a reference for the theoretical innovation and industrial implementation of the bending performance control strategy of magnesium alloys.

Rupture disk devices are non-reclosing pressure relief mechanisms employed to safeguard vessels, pipelines, and other pressure-containing components from high pressure and/or vacuum conditions. The rupture disk is also a load rate- sensitive device. Burst pressures can vary significantly with the applied pressure rate on the rupture disk device. In this study, two types of disks were manufactured using hydroforming (HF) and deep drawing (DD) processes, and the effect of load rates was investigated on burst pressure and bulge height of hydroformed and deep drawn rupture disks. First, the HF and DD processes were applied to form the rupture disks. Second, the burst of the disks was done using a waterjet machine and then simulated by ABAQUS software. The Gurson-Tvergaard-Needlemann (GTN) criterion was used to determine the parameters defining the damage in software. After validation of simulation results, the effect of load rates was investigated on the bulge height and burst pressure of HF and DD rupture disks.

This study comprehensively examined the tensile properties and damage evolution behavior of AA2024/AA7075 dissimilar alloy Friction Stir Welding (FSW) joints using the Gurson-Tvergaard-Needleman (GTN) damage model. Through integrating tensile testing, microscopic characterization, and statistical analysis, the GTN model parameters for various welding zones were accurately calibrated. A multi-region coupled refined finite element model was established. The stress-strain curves obtained from FE simulation exhibited excellent consistency with the experimental results, thereby validating the accuracy of the proposed model. It was found that the microstructural inhomogeneity of the welded joint significantly influenced the damage evolution. Specifically, the Advancing Side of Heat Affected Zone (AS-HAZ), characterized by grain coarsening and stress concentration, emerged as the primary crack initiation region. The fracture mode of the joint exhibited a mixed ductile-brittle nature, wherein second-phase particles played a critical role by promoting void nucleation and accelerating crack propagation. Damage variables rapidly accumulated within the HAZ and propagated from the center to the edge of the cross-section along the direction of maximum shear stress, eventually leading to fracture. This study clarified the damage evolution mechanism of FSW joints, providing a quantitative theoretical basis for process optimization and performance improvement of the joints.