ICTMP 2026: Papers with Abstracts

Abstract. Most of optical inorganic glass lenses and elements have been fabricated by mold-stamping above their glass-transition temperature (Tg) in industries. In this process, these glass melts above Tg, visco-elastically deformed, filled into the die cavity, and were net-shaped to the tailored optical lens and element. In this step, these melts had a risk of adhesive wear or galling to the die surface during their significantly large surface area extension under the stressed contact state to die surfaces. Hence, the die materials must have autonomous mechanism to be free from galling in addition to high heat resistance. In the cooling step across Tg, their shape and optical properties were fixed by thermal loading program. The deviation of temperature distribution in transients increased the risk of cracking and enhanced the thermal stresses. Hence, the die materials must have high thermal conductivity and toughness. As studied in [1-2], the nitrogen-doped SiC (Silicon Carbide) coating with the mm-ordered thickness, had 6H-structured microstructure with the carbon structured grain boundaries at the vicinity of contact surface. Due to its high heat-resistance and thermal conductivity, it had much less risk of thermal deviations to cause the stress-induced cracking during cooling and quenching steps toward galling-free mold-stamping.

In the present paper, the tandem-type, CNC (Computer Numerical Control) mold stamper was utilized to describe the galling-free and crack-less procedure in fabrication of the meniscus optical lenses. The boron-silicate and high-Tg glass preforms were employed as a work. SEM（Scanning Electron Microscopy）- EDS (Electron Dispersive X-ray Spectroscopy) and Raman spectroscopy were utilized to describe the in-situ formation of amorphous carbon tribofilm on the contact interface of N-doped SiC die and to analyze the carbon sp1-structuring along the grain boundaries of SiC die. The surface profilometer was used to investigate the dimensional accuracy of mold-stamped meniscus lens for practical demonstration on the usefulness of present approach.

Abstract. A duplex method has been invented and utilized as a protective coating of dies and tools to promote the wear toughness of main coating layer by inorganic buffer layer between the substrate and coating 1). DLC coating with a silicon buffer was widely used as a typical duplex coating system 2). However, the interfacial strength between the DLC coating and the buffered substrate often became insufficient to prevent the DLC-coated and buffered dies from wears in severe manufacturing conditions. A new interfacial material system design was needed to promote the interfacial strength and to significantly prolong the die and tool lives. A massive nitrogen supersaturation (MNS) was first invented to significantly harden the thick surface layer without the thermal distortion and without nitride precipitates 3). This MNSed surface layer had high nitrogen solute contents, nano-structure and high hardness. This was used as a new duplex method to improve the interfacial strength of DLC coating system 4-5).

In the present paper, AISI420 stainless steel die was first plasma nitrided to have MNSed surface layer. After forming the silicon-buffer onto this pretreated surface, DLC film was coated to build up the coating system. The indentation and scratch tests were employed to evaluate the toughness and robustness of coating system with and without the MNS pretreatment. The onset of cracking and failure was significantly retarded by this pretreatment. Microstructure analysis with XPS demonstrated that interfacial bonding state among carbon in DLC, silicon in buffer and nitrogen in MNSed layer should be responsible for strengthening and toughing of DLC coating system to prolong the die life.

Abstract. Scaling of semiconductor devices to nanometer dimensions has significantly increased their susceptibility to electrostatic discharge (ESD), making robust protection during fabrication and packaging essential for maintaining yield and reliability. However, conventional wafer carrier coatings such as micro spray coatings and hydrogenated amorphous carbon (a-C:H) films struggle to combine low surface resistance with sufficient mechanical durability. Spray coatings can provide surface resistance below 10⁹ Ω but exhibit surface hardness on the order of 1 GPa, which is inadequate under Hertzian contact pressures approaching several hundred MPa.
In contrast, a-C:H coatings can improve ESD performance by increasing the sp³ fraction, but the sp³ content is fundamentally limited in conventional chemical vapor deposition (CVD), and excessive hydrogen incorporation leads to polymer-like structures with degraded mechanical properties.
In this work, we propose a new diamond-like carbon (DLC) coating process for wafer carriers that simultaneously achieves ESD protection and high wear resistance. Using acetylene (C₂H₂) as the base precursor, we introduce tetramethylsilane (TMS, Si(CH₃)₄) during CVD to form Si–C and Si–H bonds within the DLC matrix. This approach is designed to tune the optical band gap and sp³ fraction while maintaining a dense network that delivers surface hardness above 20 GPa and surface resistance suitable for static charge dissipation. The influence of hydrogen and silicon incorporation on structure, mechanical properties, electrical behavior, and wear performance is systematically investigated to establish a framework for assessing the long-term reliability of ESD-protective DLC coatings in advanced semiconductor manufacturing environments.

Abstract. In recent years, copper-based conductive and heat dissipation components have required fine microstructures for miniaturization and enhanced functionality. Micro-forming is an excellent processing method characterized by high productivity and suitability for mass production. Due to size effects, microforming is strongly influenced by tribological conditions, making the proper setting of die surface conditions crucial. In recent years, extensive research has been conducted on surface treatments for dies, including diamond-like carbon (DLC) coatings. One of the objectives of these studies is to reduce forming force and thereby extend die life. Forming force is determined by the sum of the frictional force between the die and material surfaces and the deformation resistance of the material. Since the deformation resistance of the material is closely related to plastic flow and the formation of deformation zones within the material, it is important to understand how tribological conditions, such as die surface properties, influence these factors. However, in microforming, the effects of die surface conditions on internal deformation mechanisms and, consequently, on force behavior remain unclear.
In this study, we investigated the effect of die surface conditions on internal deformation and force behavior during micro-extrusion of pure copper. The tests were conducted using a mirror surface die with a ground finish and a DLC-coated die. The maximum force was lower for the DLC die than for the mirror surface die, demonstrating that the DLC coating provides a lubricating effect even in micro-extrusion of pure copper. Focusing on the force behavior, a convex peak behavior, considered to be influenced by changes in the microstructure during processing, was observed for both dies, and the maximum force was recorded during this behavior.
To evaluate the relationship between microstructural changes during deformation and force behavior, EBSD observations were performed on samples obtained from interrupted tests. Regardless of the die used, heterogeneous deformation occurred near the sample tip immediately after the start of the test, with deformation concentrated near the die contact surface. Nanoindentation tests revealed significant work hardening in regions where deformation was concentrated. The area exhibiting significant work hardening expanded radially inward within the billet until the maximum force was reached and then contracted thereafter. These series of phenomena were common to both dies.
To further assess the effect of die surface conditions on internal deformation, observations focusing on dislocation density were conducted. There are two types of dislocations: geometrically necessary (GN) dislocations and statistically stored (SS) dislocations. GN dislocations are required for material shape changes, and their density is known to correspond one-to-one with strain gradients. Under appropriate observation conditions, GN dislocation density near the maximum force was measured for each die to evaluate the influence of die surface conditions on internal deformation. The results showed a tendency for lower GN dislocation density in the DLC die compared to the mirror surface die. This suggesting that die surface conditions affect not only friction between the die and material surfaces but also deformation within the material.

Abstract. High-strength AA7075 aluminum alloys are essential for lightweight design in the aerospace and automotive sectors. However, their hot extrusion is limited by two critical tribological challenges, specifically tearing surface flaws and severe adhesive wear galling resulting from the reaction of alloying elements with traditional steel tools. These issues drastically reduce die service life and compromise product integrity. To overcome these limitations, this study investigates the hot tribological behavior of AA7xxx series alloys, varying the Zinc (Zn) and Magnesium (Mg) content, utilizing the conventional SKD61 die material with nitriding surface treatment.
The methodology employed the hot V-groove friction test, a specialized method simulating plastic working that combines extrusion and compression. The experimental protocol began with a Finite Element Method (FEM) simulation by using DEFORM-3D software. The FEM analysis was conducted at 400°C, 450°C, and 500°C with a diameter 7 x 70 mm specimen and a punch speed of 0.1 mm/s, systematically varying the shear friction coefficient from 0.1 to 1.0. The simulation established the essential calibration curve by plotting the shear friction coefficient (m) against the V-groove’s final aspect ratio (Height/Width). This curve quantifies the direct relationship between frictional condition and material deformation. This curve was subsequently used to determine the actual friction coefficients observed in the experimental tests. Subsequent experimental tests used AA7xxx specimens with various compositions of Zn and Mg and SKD61 die material with nitrided surface preparation under identical temperature conditions. The study concluded with elemental analysis of the V-groove tool surface using Electron Probe Micro Analyzer (EPMA) to quantify the adhesion of elements such as Mg, Zn, Copper (Cu), and Oxygen (O).
Based on the determination of the hot shear friction coefficient and the forming load, the conventional SKD61 die showed similar performance across varying alloy compositions. Crucially, elemental analysis of the tool surfaces demonstrated that adhesion phenomena were highly dependent on the AA7xxx composition. The EPMA quantified significant adhesion of alloying elements to the SKD61 die, with the concentration of these elements being correlated with the specific alloy composition tested. Understanding this adhesion mechanism is vital for guiding optimal die coating or lubrication strategies to prevent galling. This comprehensive tribological investigation provides critical data for optimizing AA7xxx alloy composition to minimize tool-die reactions, thereby mitigating surface flaws and extending die service life under nitriding conditions.

Abstract. Aluminum (Al) is highly recyclable, with the energy required to produce recycled ingots estimated to be approximately 3-5% of that needed for new ingot production. To further expand the application of recycled Al extruded products, accelerating horizontal recycling from wrought material to wrought material is necessary. A key factor hindering horizontal recycling of Al is that these recycling methods involve a casting process, where removing and neutralizing impurities introduced during casting poses a significant challenge. Since aluminum recycling currently relies on casting processes, solid-state recycling methods like extrusion processing for horizontal recycling from wrought material to wrought material are anticipated. This study aimed to achieve direct recycling of AA6063 alloy chip wastes via hot extrusion by applying stronger shear deformation to the internal material through flow separation and compression behavior using a pseudo-porthole die. Hot extrusion experiments were conducted using billet made from compacted chips of AA6063 alloy waste. The effects of extrusion temperature on extrusion properties, such as extrusion force, product surface quality, and tensile characteristics, were investigated. Increasing the extrusion temperature reduced the extrusion force. Higher extrusion temperatures improved the adhesion between individual chips, suppressed surface defects, and enhanced the tensile strength of the product.

Abstract. Friction modelling in finite element simulations is largely based on state-of-the-art analytical approaches, ranging from the Coulomb friction model and the shear friction model to advanced friction models that incorporate multiple influencing variables to represent the fluctuating contact conditions. This work presents a systematic benchmark of such state-of-the-art friction models, complemented by data-driven machine-learning-based approaches. A tribometer-based benchmark using sliding compression tests is conducted under identical boundary conditions and over a wide range of tribological loads. To enable a physically consistent comparison of fundamentally different friction formulations, model performance is specifically evaluated on the level of frictional shear stresses. The results show that the neural-network-based friction model consistently achieves the highest predictive accuracy, exhibiting the lowest prediction error. In comparison with the Coulomb model, which utilises standard constant values, the mean absolute error (MAE) is reduced from 51.38 MPa to 9.35 MPa. This equates to an error reduction of 81.8%.

Abstract. To investigate the influence of the circumferential sliding at the upper–lower workpiece contact interface on the bonding characteristics in forge-bonding with copper and aluminum workpieces, the experimental relationship between the forge-bonding conditions and the bonding characteristics was analyzed by means of machine learning analysis. The bonding probability was predicted with an accuracy of approximately 90%, while the bonding strength was predicted with an accuracy comparable to the experimental scattering. Furthermore, the circumferential sliding at the upper–lower workpiece contact interface was secondary greatest influence, following forging stroke, on both bonding probability and bonding strength.

Abstract. In cold forging, ejection forces are a key indicator of the tribological state and tool wear, as they are largely governed by the clamping pressure resulting from elastic die springback after the main forming stroke. This study investigates how an adaptive extrusion die reduces the external pressure, thereby lowering the clamping pressure and positively affecting ejection forces. A two-step model has been developed in a tribometer to represent the ejection stage. This test reproduces the tribological preloading from the main forming operation, as well as the reversal of motion under varying contact pressure. The findings from this test are transferred to the real process by finite element simulations. The results reveal a pressure-depending friction trend for polymer-based single layer lubricants in the reverse stroke, such that reducing contact pressure is accompanied by a decrease in the friction coefficient. Consequently, the beneficial effect of the adaptive die on ejection forces is not only caused by reduced clamping pressure but is further amplified by a reduction in friction. This indicates that adaptive tooling systems can contribute effectively to increased tool life.

Abstract. Amorphous electrical steel sheets were sheared using a tungsten carbide–cobalt (WC–Co) punch. To suppress crack initiation on the pierced-hole surface, the punch was first subjected to ion sharpening and subsequently laser processed to introduce a nanometer-scale periodic structure. The shearing characteristics were compared with clearance as a parameter. The fracture propagation mechanism was analyzed based on the crack behavior and the load–stroke diagrams. The results showed that the introduction of the nanometer-scale periodic structure and the reduction of the clearance to as small as 1 µm successfully suppressed crack formation, and that clearance is the dominant factor in crack inhibition.

Abstract. Evaluation of coating wear during machining is often complicated by the simultaneous occurrence of multiple failure modes such as chipping, flaking, and edge fracture. These co-existing mechanisms make it difficult to probe fundamental wear behavior. In this work, a pin-on-disc tribological test is employed as a proxy to study the tribo-chemical reactions relevant to steel machining by matching critical contact pressures and sliding velocities. Cemented carbide tools and hemispherical pins, all of which were coated with TiN, TiAlN, or AlCrN, were evaluated by machining as well as tribological tests under dry conditions. The resulting reaction products were characterized using micro-Raman spectroscopy on worn tool surfaces, machining chips, pins, and disc wear tracks.
Results reveal that Fe3O4 is the dominant oxide phase in both environments, with little Fe2O3 formation depending on the specific coating and local contact conditions. This close correspondence in oxide phases indicates that the tribo-chemical reactions of machining can be replicated under controlled laboratory conditions. Thus, pin-on-disc tribometry may be recommended as a practical, efficient method for evaluating coating performance and oxidative wear while bypassing the complexity of elaborate machining experiments.

Abstract. Predictive models are needed to design cold strip rolling pass schedules, investigate process problems and product quality. Due to the huge and complex impact of friction on this process, accurate friction models are necessary. The forward slip e.g. depends not only on average friction, but also on its space-distribution; friction also varies in time, e.g. accelerations and decelerations result in large variations of force, torque and forward slip during transients, which need to be considered in the presetting of stands.
Describing space- and time-variations of friction necessitates including the scale at which physical and chemical phenomena vary and determine friction, i.e. the microscale. This paper describes our latest efforts to enrich our mixed lubrication modelling of cold rolling, in search for a more accurate description of what is going on at asperity scale in the strip-roll interface. It involves a macroscale description of the interface temperature profile, criteria for lubricant additive desorption, for asperity scale adhesion and metallic transfer film formation, major phenomena which impact the degree of ploughing friction. Principles of the model are recalled, and the theoretical results are confronted with experiments on a high-speed laboratory rolling mill.

Abstract. The transition toward sustainable lubrication systems has driven significant research into chemically modified bio-based lubricants as alternatives to conventional mineral oils. Although mineral lubricants remain dominant in industrial applications, their low biodegradability, toxicity concerns, and reliance on non-renewable resources pose environmental challenges. Fatty acid-derived esters, particularly trimethylolpropane (TMP) esters synthesized from stearic acid, have emerged as promising candidates due to their superior lubricity, high viscosity index, and enhanced oxidative stability. However, the physicochemical and tribological performance of TMP esters is highly dependent on synthesis conditions, especially the reactant molar ratio, which governs conversion efficiency, molecular structure, and final lubricant properties. This study investigates the influence of varying molar ratios on TMP ester yield, physicochemical characteristics, and tribological behavior. Stearic acid was initially esterified with methanol, followed by transesterification with TMP. Sixteen samples with different molar ratios were synthesized within a 3 hours reaction period. Chemical transformation was verified using FTIR spectroscopy while tribological performance was evaluated using a four-ball tribotester, following ASTM D4172 standard and supported by optical microscopy analysis of wear scars. The highest conversion (98.26%) was achieved at a 5:1 molar ratio. FTIR analysis confirmed the existence of ester group in TMP backbone after the transesterification process. The 4:1 ratio exhibited the lowest coefficient of friction, achieving a 18.1% reduction compared to neat TMP, while the 3:1 ratio produced the smallest wear scar diameter, reduced by 11.12%. These findings demonstrate that molar ratio optimization plays a critical role in enhancing esterification efficiency and improving tribological performance of TMP ester bio-lubricants.

Abstract. The growing demand of biodegradable alternative for mineral-based engine oil has intensified research into vegetable oil-based lubricants capable of operating under hydrodynamic conditions without compromising environmental compatibility. However, many formulations rely on chemical additives to improve viscosity stability and load-carrying performance, potentially reducing biodegradability. This study proposes an additive-free lubricant formulated by blending palm-oil-based trimethylolpropane ester (PO-TMP) with refined coconut oil (CO) and evaluates its hydrodynamic performance in journal bearing applications. Blend C75, containing 75 vol% CO and 25 vol% PO-TMP, was prepared and compared with neat CO, PO-TMP, and SAE 40 mineral oil. Hydrodynamic testing was conducted under a constant radial load of 10 N and rotational speeds from 200 to 2000 rpm using a journal bearing rig equipped with circumferential pressure and temperature sensors, while frictional torque measurements enabled coefficient of friction evaluation. Analytical predictions of minimum film thickness and load-carrying capacity were obtained from the Reynolds equation for short journal bearings. Blending PO-TMP with coconut oil significantly improved viscosity stability without additives, with C75 exhibiting the highest viscosity index (265.8). Despite lower absolute viscosity than SAE 40, C75 generated higher maximum hydrodynamic pressures at all speeds, reduced bearing temperature rise, and maintained the lowest overall friction, achieving an average COF reduction of approximately 25%. The balanced molecular structure of C75 enabled the formation of sufficient film thickness to sustain load-carrying capacity comparable to mineral oil. These findings demonstrate that tailoring complementary vegetable oil structures can enhance viscosity stability, pressure generation, and friction performance while preserving biodegradability, demonstrating C75 as a suitable alternative for mineral oil-based lubricant for journal bearing application.

Abstract. Hard coating possibly improves die-life for the cold forming. Moreover, PVD-coated tools retain precise geometries due to lower coating temperature. However, many micro droplets scatter on the PVD-coated tool by arc ion plating. In this paper, the influence of micro droplets on tribological conditions was investigated when TiN-coated tools with the micro droplets were used for a tapered-plug penetration test. The forming load and the surface quality were estimated in the test. These were damaged by adhesion under the condition of a thin lubricant film between the tool and workpiece, while the micro droplets cannot affect both tools and workpiece under another well lubrication condition of a thick lubricant film.

Abstract. Dimensional stability and interfacial friction remain critical challenges in precision aluminum tube manufacturing. This research investigates the influence of asymmetric plastic flow and tribological conditions on cold-drawn AA3003-F tubes through a systematic experimental investigation (N=30). Preliminary physical trials revealed that unlubricated drawing causes immediate tensile fracture at the tube head due to extreme interfacial friction, whereas the drawing process is successfully stabilized under a steady-state boundary lubricant (μ=0.099). During drawing, an initial eccentricity (2.34%–7.89%) acts as a catalyst, triggering a three-dimensional tilt of the cantilevered mandrel head under asymmetric drawing loads. This induces a highly unbalanced macro-residual stress distribution (ranging from -6 to -45 MPa as quantified via X-ray diffraction), where compressive residual stresses systematically concentrate in the thicker wall sectors. Mechanistically, this circumferential disparity drives inhomogeneous elastic recovery, generating an internal residual bending moment (M_RS) that severely deteriorates the longitudinal straightness from 1.080±0.669 mm/m to 2.973±0.942 mm/m. Concurrently, the ultimate tensile strength (UTS) increased from 140.26 ± 1.55 MPa to 151.11 ± 1.70 MPa, while ductility dropped severely, with elongation plummeting from 22.00% to 9.13% as the material reached its plastic instability limit. Crucially, the circumferential uniformity of Vickers hardness (44–45 HV) and stabilized X-ray line profile Full Width at Half Maximum (FWHM of 1.76–1.83 deg) confirm that the bowing defect is a macroscopic structural phenomenon arising from tool-workpiece mechanics rather than localized material defects. These findings emphasize the critical need for stringent initial geometry control, alongside the use of fully-constrained tooling systems and optimized lubrication, to ensure the longitudinal accuracy of the final component.

Abstract. Solid-state recycling has emerged as an energy-efficient alternative to conventional remelting for aluminum scrap; however, its effectiveness depends on achieving sufficient metallurgical bonding between oxide-covered aluminum chips during consolidation. In this study, AA6063 aluminum chips were consolidated using a multi-stage billet packing technique followed by hot extrusion through a modular die system incorporating normal and strain gradient feeder geometries. The consolidated products were evaluated by optical microscopy and tensile testing to investigate the influence of material flow on consolidation behavior. Microstructural observations showed that hot extrusion effectively eliminated most of the large packing voids, although localized oxide-rich interfaces and residual chip boundaries remained within the recycled material. Tensile testing demonstrated that the recycled chip billet achieved an ultimate tensile strength comparable to that of a conventional cast billet while exhibiting a higher yield strength, indicating effective solid-state bonding during extrusion. The observed microstructural evolution and mechanical response were interpreted from a tribological perspective, highlighting the role of friction and interfacial shear in oxide fragmentation and chip-to-chip bonding. The proposed strain-gradient feeder provides a practical approach for enhancing localized deformation and offers a promising die-design strategy for improving the consolidation efficiency and performance of solid-state recycled aluminum.