High Deformation Research Articles

Microstructural evolution and high strain rate deformation response of SLM-printed CoCrFeMnNi after annealing and deep-cryogenic treatment

This study examines the microstructural evolution and high strain rate deformation response of Selective Laser Melted (SLM) CoCrFeMnNi high entropy alloys (HEAs) after annealing and deep cryogenic treatment. Annealing treatment has traditionally improved the ductility of selectively laser melted (SLM) materials. However, in this work, significant improvement in strength was observed in the annealed SLM CoCrFeMnNi after observing the high strain rate deformation response. TEM/HRTEM investigations revealed the formation of refined oxides, derived from the processing chamber and constituent powder feedstock. These oxides were homogenously distributed within microstructure reinforcing its structural integrity. Initial microstructural analysis of the as-printed samples showed the originally Mn2O3 oxides sparsely distributed within a cellular dislocation structure and significant Mn segregation. Unique grain growth with less prominent cellular dislocation structure were observed in the annealed specimen. Deep cryogenic treatment induced oriented cellular structures with higher dislocation density and round oxides 56 % smaller. High strain rate impact tests (up to 6500 s-1) demonstrated that the as-printed sample was sensitive to the strain rate and reached a yield strength of ~920 MPa at 6000 s−1 and strain deformation of ~55 % proving desirable for high strain rate applications. Remarkably, ~10 % higher ductility and strength, up to 22 % after annealing was achieved. The strengthening mechanisms in the samples and their contributions to the overall material strength were thoroughly analyzed. It was determined that a substantial portion of the strength in the annealed samples was due to the contributions of the precipitates within the alloy. The observed increase in strength was primarily attributed to the presence of two distinct nano-precipitates in the annealed specimens. However, there was no change in ductility after the deep cryogenic treatment but ~10 % higher yield strength values at equivalent strain rates also attributed to the increased dislocation density.

Abstract A004: Full spectrum isolation technique-based dual circulating rare cells analysis to maximize early cancer diagnosis

Abstract Liquid biopsy (LB) is essential in precision medicine, enabling real-time tumor monitoring through repeated sampling. However, its diagnostic sensitivity and accuracy are limited by the low detection rate of circulating tumor cells (CTCs). For example, in breast cancer, the CTC detection rate exhibited only 20%, significantly limiting its clinical utility. This limitation arises since existing technologies selectively isolate specific phenotypes of CTCs, failing to capture others, such as mesenchymal CTCs, which are associated with poor prognosis. These mesenchymal CTCs often evade detection due to their lack of EpCAM expression and high deformability, making difficult to isolate them with traditional filter or EpCAM based methods. Additionally, conventional LB methods fail to provide critical insights into the tumor microenvironment (TME). To overcome these limitations, we developed a novel approach that improves LB diagnostic sensitivity and accuracy by (1) creating a technology to isolate all types of CTCs, regardless of marker expression or size, and (2) simultaneously analyzing CTCs and circulating cancer-associated fibroblasts (cCAFs). This dual approach addresses the challenges of low sensitivity and accuracy by enabling the isolation of a broader range of CTCs, including mesenchymal types, and by incorporating cCAF analysis. cCAFs, derived from the TME and found in the bloodstream, provide valuable insights into the TME that are hard to obtain through traditional methods. Analyzing cCAFs alongside CTCs offers a more comprehensive understanding of tumor biology and its microenvironment, leading to improved diagnostic accuracy, especially in early-stage cancer. In our study involving 55 breast cancer patients, we demonstrated that while CTCs were undetectable in 42.9% of early-stage patients, cCAFs were detected in all cases and were found to be 10 times more abundant than CTCs. Importantly, for the first time, this study uncovers that the diverse CAF subtypes previously identified in tissue samples also exist in the bloodstream, highlighting their critical role in providing TME-related insights. In addition, cCAF subtypes vary with hormonal receptor expression, and their marker analysis allows for 80.9% accurate classification of breast cancer subtypes. We applied this approach to early-stage breast cancer patients, for whom diagnosis through liquid biopsy is particularly difficult, and found that the combined analysis of CTCs and cCAFs achieved a 18% improvement in accuracy, with the AUC increasing from 0.6817 to 0.8009 compared to CTC analysis alone. This innovative approach significantly enhances LB by simultaneously isolating all CTC subtypes and incorporating cCAF analysis, thereby offering a more sensitive and accurate diagnostic tool. Beyond improving breast cancer diagnostics, this method has the potential to be applied to other tumor types and could also prove valuable for prognosis prediction and therapeutic response monitoring, ultimately leading to better patient outcomes and more effective cancer treatment strategies. Citation Format: Hyeongjung Woo, Simon A Joosse, Frederike Harten, Felix Hilpert, Klaus Pantel, Minseok S. Kim. Full spectrum isolation technique-based dual circulating rare cells analysis to maximize early cancer diagnosis [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A004.

Flattening behaviour of weft-knitted spacer fabrics

AbstractWeft-knitted spacer fabrics are thick 3D knitted structures prized for their cushioning properties which have gathered increasing attention in the last decade. The thickness of a spacer fabric is one of its most influential parameters and strongly impacts its cushioning properties, wearability, thermal insulation or permeability. However, the fabric's natural undulation and high deformability make its thickness measurement uneasy. The current standard measurement methods require to measure the fabric thickness after compressing it until a fixed threshold stress value is reached to flatten it. The diversity of these threshold values is confusing, and each of them is unsuitable to variety of fabric rigidity. In this article, a standard for thickness evaluation was proposed and used to measure the thickness of 20 samples knitted with 5 independent parameters. The measured thickness was compared to the thickness measured at a threshold value of 1 kPa and to a theoretical thickness. The proposed measurement standard was proved reproducible and efficient for all fabrics when the threshold measures showed large errors on the softer and stiffer samples. The flattening stress of the fabrics ranged from 86 to 5262 Pa and could not be approximated by a single standard value. The theoretical thickness was more accurate, predicting the thickness with an average error of 3.8%.

Perindopril erbumine-entrapped ultradeformable liposomes alleviate sarcopenia via effective skin delivery in muscle atrophy mouse model

Sarcopenia is a pertinent challenge in the super-aged societies causing reduced functional performance, poor quality of life and increased morbidity. In this study, the potential of perindopril erbumine-loaded ultradeformable liposomes (PE-UDLs) against sarcopenia was investigated. PE-UDLs were prepared by thin-film hydration and extrusion method using egg yolk phosphatidylcholine (EPC) as a lipid bilayer former and Tween 80 or sodium deoxycholate as an edge activator. Owing to the smallest particle size (75.0 nm) and the highest deformability (54.2) and entrapment efficiency (35.7 %), PE-UDLs with EPC to Tween 80 ratio of 8:2 was selected as the optimized formulation. The optimized PE-UDLs showed substantially higher cumulative amount of drug permeated and permeation rate across the rat skin compared to PE solution (485.7 vs. 50.1 µg and 13.4 vs. 2.3 µg/cm2/h, respectively). Topically applied PE-UDLs successfully ameliorated the effects of lipopolysaccharide (LPS)-induced sarcopenia in mice by improving body weight changes, grip strength and muscle weight. Furthermore, PE-UDLs reduced the shrinkage of muscle fibers as demonstrated by higher cross-sectional area than PE solution. PE-UDLs also increased the expression of myosin heavy chain (MHC) protein and reduced the expression of muscle atrophy F-box (Atrogin-1) and muscle ring-finger protein-1 (MuRF1), thereby improving muscles atrophy. In conclusion, these results demonstrate the therapeutic potential of PE-UDLs against sarcopenia.

Bubble boundary R-CNN: A multitask model for segmenting and reconstructing overlapping bubbles

When measuring the dynamic characteristics of bubbles using image-based methods, the images including complex overlapping of bubbles with irregular shape pose a huge challenge to current bubble reconstruction algorithms. Based on the Mask R-CNN architecture, a multitask model “Bubble Boundary R-CNN” is proposed for detection, segmentation and shape reconstruction of overlapping bubbles with high deformation at high gas velocities. By leveraging shared deep features from detection and segmentation, model achieves flexible bubble reconstruction and accurate size distribution extraction from high gas velocity bubble flows. To overcome the limitations of Mask R-CNN and address the challenges posed by high-deformation and overlapping bubbles, a semantic segmentation auxiliary head and the Boundary-preserving Mask Head (BMask Head) are introduced to enhance edge information and extract bubble boundary features. Additionally, an Overlapping Boundary Prediction Network (OBPN) is proposed to reconstruct boundary features that are lost due to bubble occlusion and predict the complete bubble shapes. The optimized model shows its ability to flexibly and accurately reconstruct overlapped and deformed bubbles by varying occlusion rates and circularity. The new model has also proven its reliability when applied to bubble images from a bubble column at gas velocities of up to 0.067 m3/s. In future work, more efforts are needed to further enhance the detection capability of the model and reduce missed and multiple detections at high gas velocity.

Enhanced strength-ductility synergy in a Ni–W–Co–Ta medium-heavy alloy via cryogenic supersonic fine particle bombardment

This study explores the influence of cryogenic supersonic fine particle bombardment (CSFPB) on a Ni–W–Co–Ta medium heavy alloy (MHA), and focus on the effect of gas pressure and impact time on the surface integrity, microstructural evolution, and mechanical properties of the MHA. CSFPB treatment creates a gradient structure, including surface layer with nanograins down to 9.0 nm due to severe plastic deformation, subsurface layer with high density dislocation structures and deformation twins due to weakened impact energy, and undeformed matrix. A key advantage of CSFPB is seen to be the cryogenic environment, which promotes superior surface integrity by reduced roughness. As the impact duration and gas pressure increase, the depth of deformation layer, surface hardness and strength of the MHA progressively rise. The optimal combination of strength and ductility is achieved at a gas pressure of 1.0 MPa for a duration of 90 s. This setting results in a maximum ultimate tensile strength of 1351 MPa and yield strength 796 MPa, with uncompromising elongation. However, excessively long treatment durations or high gas pressures can lead to the formation of surface microcracks, ultimately reducing the MHA's strength. Therefore, CSFPB offers the benefit of improved surface integrity through the cryogenic environment while maintaining a desirable balance between enhanced strength and ductility.

An asymmetric pinching damaged hysteresis model for glubam members: Parameter identification and model comparison

The performance of glue laminated bamboo (glubam) members is governed by the nonlinear response at their joints, where high deformation levels and stress concentrations are developed. Numerous phenomenological models are presently employed to describe the hysteresis behavior of these joints, while these models always have an excessive number of parameters, and the physical interpretation of these parameters is often challenging. Moreover, some hysteresis models cannot capture all hysteresis features such as asymmetry, pinching, and damage. Consequently, this paper introduces a novel phenomenological-based hysteretic model named Asymmetric Pinching Damaged (APD) model, and implemented it in Abaqus by combining connector and spring elements in series or parallel. This model encompasses asymmetry, pinching, and strength degradation for bamboo joint components, with parameters that possess clear physical meanings and are readily comprehensible. This study also presented a parameter identification framework coupling the Parallel Genetic Algorithm (PGA) and Bayesian Neural Network (BNN). By merging the FE modeling and optimizing algorithms with the interactive application of ABAQUS and Python software platforms, the integrated identification framework is capable of performing multi-threaded parallel computation of finite element models considering the BNN-based uncertainty quantification, thus greatly improving the efficiency of parameter identification.

The effect of Mg17Al12 intermetallic compound on dynamic recrystallization of cast-forged AZ80 magnesium alloy

An asymmetric I-crossbeam geometry is produced by cast-forging of the AZ80 magnesium alloy at two different casting cooling conditions and three different forging temperatures. Samples are extracted from two different locations from each component, representing different deformation conditions, for microstructure study. This paper presents a detailed investigation into the relationship between the Mg17Al12 intermetallic compound and dynamic recrystallization in the cast-forging process. The eutectic, lamellar, discontinuous, and continuous morphologies of the Mg17Al12 phase are observed in the produced components, and their evolution during the cast-forging process is investigated. Depending on the forging condition, dissolution and re-precipitation of the Mg17Al12 phase might occur before or after the forging stage and influence the extent, distribution, and grain size of DRX. It is shown that the eutectic, lamellar, and discontinuous morphologies of the Mg17Al12 phase effectively promote dynamic recrystallization. On the other hand, the continuous morphology is only effective when the particles are broken as a result of high deformation. This study provides a better understanding of the effect of Mg17Al12 intermetallic compound on the hot deformation behavior of the AZ80 alloy, which can be used to tailor the cast material in order to improve the forgeability and final mechanical properties of the magnesium-based structural components.

3D-Printed Multi-Axis Alignment Airgap Dielectric Layer for Flexible Capacitive Pressure Sensor

Flexible pressure sensors are increasingly recognized for their potential use in wearable electronic devices, attributed to their sensitivity and broad pressure response range. Introducing surface microstructures can notably enhance sensitivity; however, the pressure response range remains constrained by the limited volume of the compressible structure. To overcome this limitation, this study implements an aligned airgap structure fabricated using 3D printing technology. This structure, designed with a precisely aligned triaxial airgap configuration, offers high deformability under pressure, substantially broadening the pressure response range and improving sensitivity. This study analyzes the key structural parameters—the number of axes and pore size—that influence the compressibility and stability of the dielectric material. The results indicate that the capacitive pressure sensor with an aligned airgap structure, manufactured via 3D printing, exhibits a wide operating pressure range (50 Pa to 500 kPa), rapid response time (100 ms), wide limit of detection (50 Pa), and approximately 21 times enhancement in sensitivity (~0.019 kPa−1 within 100 kPa) compared with conventional bulk structures. Furthermore, foot pressure monitoring trials for wearable sensor applications demonstrated exceptional performance, indicating the sensor’s suitability as a wearable device for detecting plantar pressure. These findings advocate for the potential of 3D printing technology to supplant traditional sensor manufacturing processes.

Mechanical Responses and Deformation Mechanisms of Low-cost High-entropy Alloy AlCrFe2Ni2 with Heterogeneous Structure Subjected to High Strain Rate Deformation

Mechanical Responses and Deformation Mechanisms of Low-cost High-entropy Alloy AlCrFe₂Ni₂ with Heterogeneous Structure Subjected to High Strain Rate Deformation

Improvement of Thermal Stability of Charges in Polylactic Acid Electret Films for Biodegradable Electromechanical Sensors.

Eco-friendly sensors fabricated from biocompatible and biodegradable materials are promising candidates for wearable and implantable electronics due to their environmental sustainability and biosafety. This article reports a fully biodegradable electromechanical sensor (FBES) utilizing a sandwich structure with macro ripple structured polylactic acid (PLA) electret films acting as sensitive layers and molybdenum (Mo) sheets serving as electrodes for a wearable device application. The stability of the space charge stored within the PLA film has been enhanced by introducing an internal cellular structure and improving the polarization process. A macro ripple structure of the PLA layer with higher deformation is a great guarantee for boosting the pressure sensitivity. The results indicate that inserting cell microstructures and optimizing the polarization process significantly improve the charge storage stability of PLA films by nearly 55%. This enhancement is attributed to several factors, including the extended charge drift path of the charges in cellular films, a synergy effect of surface charges, and "macroscopic" dipole charges distributed in the cells. The fabricated sensor achieves a high sensitivity of 1000 pC/kPa, a wide pressure detection range of 0.03-62.4 kPa, and satisfactory stability. Such sensors are not only sensitive to body movements but also to subtle physiological signals, satisfying the diverse needs of wearable healthcare. Importantly, all the composition materials of the sensor can be completely degraded after their service, aligning with the environmentally friendly principles of green development.

Constructing Long and Stable Ag‐Al2O3 Core–Shell Nanowires for Humidity Sensing and Triboelectric Energy Generation

Silver nanowires (AgNWs) are a promising alternative material to indium tin oxide as flexible transparent electrodes owing to their excellent optoelectrical properties and mechanical performance. However, the main challenge is the poor stability under diverse environments, ranging from high humidity, chemical exposure, and dynamic mechanical deformation. Herein, ultralong AgNWs (≈100 μm) have been synthesized via controlling growth kinetics by a facile acetic acid‐assisted solvothermal method, further decorated with a thin Al2O3 layer by electrodeposition to form a core–shell architecture. The resultant films based on Ag‐Al2O3 core–shell nanowires (NWs) possess a higher conductivity while preserving the optical transparency due to the enhanced NWs contact. More importantly, the constructed films exhibit strong resistance to various conditions, such as exposure to high temperature/humidity and immersion in NaCl, HCl, and Na2S solutions. The laser‐etched interdigital electrodes based on the chemically stable AgNWs are further integrated with graphene oxide layer for humidity sensing and respiration monitoring. Furthermore, the developed NWs with superior mechanical stability are constructed as triboelectric nanogenerators for electricity generation, and reliable output performance has been demonstrated. This work provides a convenient, scalable, and cost‐effective solution that offers great potential for designing robust, transparent electrodes for next‐generation flexible electronics.

Thermal processing behaviour and microstructural evolution of high W and high γ’ content extruded nickel-based powder metallurgy superalloy FGH4109

ABSTRACT Nickel-based powder metallurgy superalloys with high W and high γ’ content exhibit excellent high-temperature properties, but their high deformation resistance poses significant challenges for hot processing. In this study, the hot compression behaviour of an extruded nickel-based powder superalloy FGH4109 with high W (6.1%) and high γ’ phase contents (60%) was systematically investigated at temperatures ranging from 1060 ℃ ~ 1140 ℃, strain rates from 0.001 s−1 ~1 s−1, and maximum true strains of 0.7. Combined with the hot working map and the microstructure evolution in different hot working zones, the optimal hot working window for the alloy was determined to be in the temperature range of 1060 ℃ ~ 1140 ℃ and strain rates of 0.001 s−1 ~0.012 s−1, where the power dissipation efficiency η was greater than 0.5, and the dominant deformation mechanism was discontinuous dynamic recrystallisation.

Mechanical properties of aramid and UHMWPE thermoplastic composites: numerical and experimental trials

The out-of-plane behaviour of 8 different composites exposed to very high deformation rates and non-standard conditions was investigated in our previous studies. The mechanical properties of these composites have been evaluated through tests conducted at deformation rates comparable to those experienced during explosions. Based on the relevant test results, this study conducted a numerical analysis of 3 best-performing Aramid UD GS3000, Artec Aramid/Woven Aramid CT736, and H62 UD-UHMWPE-reinforced composites. In this regard, LS-DYNA's MAT54 model was compared with other failure mechanics-based models and preferred because it requires less experimental data and can simulate damage progression in dynamic failures. Since the samples used in the study were non-standard, quasi-static tensile and shear tests were performed based on the loads to which the composites would be exposed to create an accurate numerical analysis. Both tensile and shear strength values of the Artec Aramid/Woven Aramid CT736 composite are higher than those of the Aramid UD GS3000 and H62 UD-UHMWPE composites. When the numerical analysis results were compared with the tensile test data, compliance rates of 99.84% for Aramid UD GS3000 reinforced composite, 99.34% for Artec Aramid/Woven Aramid CT736 reinforced composite, and 96.42% for H62 UD-UHMWPE reinforced composite were determined. The analysis showed that the shear stress-strain curves provided 100% agreement at the maximum stress value.

Effect of pressure on the sintering mechanisms of tantalum carbide ceramics

AbstractHigh pressure sintering shows great superiority in promoting the densification of the hard‐to‐densify refractory ceramics, and the underlying mechanisms are thus of great interest. In the present work, the densification process of tantalum carbide (TaC) ceramics affected by pressure was discussed through comparing the microstructural characteristics and sintering kinetics. The TaC ceramics sintered at 30–250 MPa show dense and uniform microstructure without oxide impurities and high‐density dislocations. With the increase of sintering pressure, particle rearrangement becomes prominent at initial stage, whereas grain boundary diffusion rather than lattice diffusion dominants the final stage mechanism. Grain growth is enhanced under high pressure through the plastic deformation process. Our work should facilitate to understand the mass transport mechanisms during the high pressure sintering or deformation process of carbide ceramics.

Dough kneading load simulation for stand mixer using smoothed particle hydrodynamics approach

Stand mixer is a consumer-durable appliance, primarily used for kneading, whipping, shredding, mixing, scrambling, etc. During the kneading process, there arises a situation when the hook gets stuck or the stand mixer starts to wobble or shake. Repercussions of these phenomena could lead to overheating of the transmission system, inability of the stand mixer to provide the required torque, bowl stripping out, etc. Usually, in industries, physical tests are carried out to determine the torque load exerted on the stand mixer. Hence, through this research, we intend to develop a simulation methodology to determine the torque load exerted by the dough on the stand mixer during the kneading process. The proposed research comprises the dough material model, the application of the smoothed particle hydrodynamics (SPH) approach for representing the dough material, due to its ability to withstand high deformation and shearing loads, and the development of simulation methodology. Sensitivity analysis was also carried out to examine the effect of various parameters on the simulation results.

Magnetostrictive Behavior of Severe Plastically Deformed Nanocrystalline Fe-Cu Materials

Reducing the saturation magnetostriction is an effective way to improve the performance of soft magnetic materials and reduce core losses in present and future applications. The magnetostrictive properties of binary Fe-based alloys are investigated for a broad variety of alloying elements. Although several studies on the influence of Cu-alloying on the magnetic properties of Fe are reported, few studies have focused on the effect on its magnetostrictive behavior. High pressure torsion deformation is a promising fabrication route to produce metastable, single-phase Fe-Cu alloys. In this study, the influence of Cu-content and the chosen deformation parameters on the microstructural and phase evolution in the Fe-Cu system is investigated by scanning electron microscopy and synchrotron X-ray diffraction. Magnetic properties and magnetostrictive behavior are measured as well. While a reduction in the saturation magnetostriction λs is present for all Cu-contents, two trends are noticeable. λs decreases linearly with decreasing Fe-content in Fe-Cu nanocomposites, which is accompanied by an increasing coercivity. In contrast, both the saturation magnetostriction as well as the coercivity strongly decrease in metastable, single-phase Fe-Cu alloys after HPT-deformation.

Environmental Impact of Polyurethane-Based Aerogel Production: Influence of Solvents and Solids Content

This study provides a comprehensive analysis of the environmental impacts associated with the synthesis of polyurethane (PUR) aerogels. The synthesis process incorporates various solvents and solids contents into the formulation, with the primary objective of enhancing the physical properties of the aerogels for broad industrial applications. Nine experimental scenarios were explored, grouped into two sets based on the variables studied. A detailed Life Cycle Assessment (LCA) was conducted to evaluate the environmental impacts of all formulated PUR aerogels. The findings indicate that a solvent solution of 100% ethyl acetate (EtOAc) results in lower environmental impacts compared to other tested formulations. Notably, a solvent solution comprising 75% acetonitrile (ACN) and 25% EtOAc exhibited the highest environmental Key Performance Indicator (εKPI) among the tested material formulations, closely followed by the PUR aerogel obtained using acetone as a solvent. Furthermore, this study underscores the necessity of performing an integrated LCA that considers both environmental and functional aspects. While reducing the solids content is environmentally advantageous, it may present challenges in terms of material functionality. This is illustrated by the PUR aerogel synthesized with the lowest solids content of 3.2 wt.%, which demonstrated high deformability, thereby complicating the determination of a reliable Young’s modulus for analysis.

CT-guided infiltration of the ischiofemoral space in young patients with ischiofemoral impingement is an effective diagnostic tool.

To present our technique of diagnostic CT-guided ischiofemoral space injection and report on pain response, complications, and associated imaging findings in young patients with ischiofemoral impingement (IFI). Retrospective case series of patients with a clinical diagnosis of IFI that underwent CT-guided IFS injection with local anesthetic in a prone position with the feet in maximum internal rotation between 06/2019 and 04/2021. The response was evaluated using maximum subjective pain evaluation on a 0-10 visual analog scale (VAS) during a standardized pre- and postinterventional clinical examination. Patient charts and radiographic imaging data were reviewed to report associated imaging findings and subsequent surgeries. Eleven patients (13 hips, 9 females) with a median age of 31 years (interquartile range; IQR: 25-37 years) were included. Median baseline VAS was 7 points (IQR: 5-8) with a pain reduction of 5 points (IQR: 5-7 points, p = 0.001) after the injection. One patient reported transient ischial nerve paresthesia, otherwise, no complications occurred. Quadratus femoris muscle edema was present in 85% (11 of 13 hips). Excessively high femoral torsion (11/13 hips, 85%) and cam deformities (8/13 hips, 62%) were the most common osseous deformities. Eight of 13 hips (62%) underwent subsequent surgery for IFI. CT-guided diagnostic injection of the ischiofemoral space is safe and feasible. In young IFI patients, diagnostic IFS injections have the potential to improve the differential diagnosis of hip pain and to inform decision-making with regard to a possible benefit of joint-preserving hip surgery. In young patients with hip pain, diagnosis of IFI can be challenging due to concomitant pathologies. Furthermore, surgical treatment in these patients is controversial. In this context, CT-guided diagnostic infiltrations of the ischiofemoral space may facilitate not only the initial diagnosis of IFI, but could also improve surgical decision-making. CT-guided diagnostic injection of local anesthetic in the ischiofemoral space is safe. In young patients with IFI, it leads to subjective pain reduction. In young patients with concomitant osseous deformities, it may improve surgical decision-making.

STUDY ON THE INFLUENCE OF 1 AND 15μm PITCH VALUES ON THE APPARENT NANOMECHANICAL PROPERTIES OF LASER POWDER BED FUSION-PRODUCED CuCrZr ALLOY

Material deformation due to nanoindentation is well known. However, the deformation of a material, indentation cavity, and piled-up region drastically increases and nanohardness significantly decreases if the nanoindentation is performed in such a way that the deformation of one nanoindentation affects the others. This situation arises in various materials when they are subjected to tribological application such as pantograph assembly in electric trains and contact between the electrical power supply plug and pins. This situation has been addressed in this study and the quantitative reduction in nanohardness has been evaluated in detail. In this work, the nanoindentation was performed on the laser powder bed fusion (LPBF) CuCrZr alloy specimen under a load condition of 4500[Formula: see text][Formula: see text]N. This test was conducted at 100 points with an array of [Formula: see text] at a 1[Formula: see text][Formula: see text]m pitch value. Two significant findings were identified in this work. First, the indentation impression was smaller and the corresponding nanohardness and contact stiffness values were higher in the first column of 10 nanoindentations and the first row of 10 nanoindentations. The remaining 80 nanoindentations displayed contrasting behavior compared to the initial 20 nanoindentations due to the prior deformation of nearer regions. Nanohardness value decreased parabolically from the low deformation to the high deformation region. This finding was validated by increasing the pitch to 15[Formula: see text][Formula: see text]m under the 4500[Formula: see text][Formula: see text]N load conditions. The piled-up region around the impression of indentation changed from a semi-circular shape at a 15[Formula: see text][Formula: see text]m pitch value to a cone shape at a 1[Formula: see text][Formula: see text]m pitch value. These findings will be beneficial for industries during the design of materials and will help reduce material failures resulting from tribological activities.