Μm Layer Research Articles

Different post-heat treatment responses on microstructure and mechanical characteristics of maraging steel 1.2709 samples produced by LPBF

Abstract The study focuses on the enhancement of microstructural and microhardness characteristics of Laser-Based Powder Bed Fusion (LPBF) maraging steel 1.2709 with the effect of different heat treatment (HT) conditions including aging (AT), double aging (DAT), and solutioning (ST) and compared with the as-built (AB) condition. The samples were fabricated with the LPBF process parameters, utilizing 120 W of laser power, 500 mm s−1 of scanning speed, maintaining 20 μm layer thicknesses, with the laser spot width and hatch spacing of 0.0550 mm and 100 μm respectively in the argon environment with the 45° rotating raster scanning pattern. Further the as-built and heat treated samples were evaluated utilizing electron backscatter diffraction (EBSD), Field Emission Scanning Electron Microscope (FESEM), microhardness, x-ray diffraction (XRD) and relative density. The FESEM analysis indicated that the DAT samples exhibit a more refined and uniform interdendritic grain growth of precipitates Ni3 (Al, Ti) compared to the as-built sample, which exhibited porosity and lack of fusion. Aging reduces the presence of interlayer defects, while the solution-heat-treated sample reveals the formation of lath martensite. The microhardness exhibited an increase following three distinct heat treatment conditions: AB, AT, DAT, and ST, measuring 450 HV, 650 HV, 760 HV, and 520 HV, respectively. The ferrite content was recorded at 99.6%, 87.4%, 99%, and 99.4%, while the austenite content was 0.4%, 12.6%, 1%, and 0.6%. The grain size in the ferrite phase was 8.72 μm, 6.087 μm, 6.86 μm, and 0.32 μm, and in the austenite phase the grain size was 0.26 μm, 0.86 μm, 2.51 μm, and 6.89 μm.

The influence of 3-dimensional printing layer thickness on model accuracy and the perceived fit of thermoformed retainers.

This study aimed to investigate the accuracy of dental model printing using 2 different layer height settings and how these settings affect the fabrication of thermoformed retainers. Subjects were recruited from the Department of Orthodontics at Case Western Reserve University and scanned according to specific selection criteria. A total of 30 stereolithography files were produced and used as reference files. The stereolithography files were printed at the recommended layer height of 100 μm and 170 μm with a Sprint Ray Pro 95 3-dimensional (3D) printer (Sprint Ray, Los Angeles, Calif). All printed models were scanned using the same iTero intraoral scanner (Align Technology, San Jose, Calif) as was used for the initial intraoral scan as well. The accuracy of the printed models was based on the evaluation of root mean square values resulting from 3D superimpositions. Afterward, vacuum-formed retainers were fabricated. The vacuum-formed retainers were evaluated by the patient and an American Board of Orthodontics-certified orthodontist. No difference was observed in the maxillary arch (P= 0.85) and the mandibular arch accuracy (P= 0.08) by assessing the root mean square values. No difference was observed in the doctor retainer score of the maxillary retainers (P= 0.37) and the mandibular retainers (P= 0.77). There was no difference in the patient retainer score of the maxillary (P= 0.08) and the mandibular retainers (P= 0.22) when comparing retainers. Conversely, less printing time was observed when printing the models with 170 μm compared with 100 μm (P<0.001). The accuracy of a dental model printed with a Sprint Ray Pro 95 3D printer was not affected by the 100 or 170 μm layer height. Orthodontists and patients did not detect a statistically significant difference in retainer fit.

Performance of Gears Manufactured Through Additive Manufacturing

Bound metal deposition (BMD) additive manufacturing technique was used to fabricate gears of PH 17-4 stainless steel material. The gears were fabricated with different layer heights (namely 150 μm and 50 μm) and also subjected to post-fabrication machining. Each gear was tested against commercially available gear in a high-precision control test rig. The operational temperature and noise level were measured during the test, while the material loss due to wear was evaluated at the end of the test. The 50 μm layer height gear performed the best with the least wear loss, minimum noise generation, and temperature rise. The 150 μm layer height gear, which was mechanically polished, performed very similarly to it (50 μm layer height gear) and cost 33% less to print; thus, it was considered the best performing when cost was incorporated. The conclusions found that post machining of printed parts greatly impacts their performance, and thus, the post-print conditions should be considered just as much as the printing conditions.

Environmental effects on the performance and emission characteristics of adding diethyl ether into a biodiesel-powered LHR engine

ABSTRACT Biodiesel is considered as a viable alternative in regions where traditional diesel fuel is not readily available. In an effort to improve the diesel engine efficiency under these circumstances, combustion components were treated with a coating of partially stabilized zirconia with a 500 µm layer coating using plasma coating technology. In this study, the engine was powered by neat coconut waste cooking oil (CWCO) with diethyl ether (DEE) serving as an additive. A fuel mixture comprising 90% CWCO and 10% DEE was used to compare the performance of coated and uncoated engines to diesel fuel standards. Direct-injection compression ignition engine, tested with loads up to 12 kgf, showed lower BSFC and improved BTE despite lower NOx emissions. HC, CO, and smoke emissions were 18%, 11%, and 19% lower in blends in the 90% CWCO and 10% DEE than blends compared to diesel fuel at higher loads.

Analysis and Performance Evaluation of Non-Toxic Organo-Metal Halide (CH3NH3SnI3) Perovskite Optical Absorber based Photovoltaic Cell

Tin-based Perovskite solar cells (PSC) have emerged as a promising alternative to environmentally hazardous lead-based Perovskite solar cells. The lead-free Perovskite compound (CH3NH3SnI3) is particularly appealing due to its wide absorption spectrum. Perovskite materials both organic and inorganic, exhibit exceptional optical features such as a high absorption coefficient, a tunable band gap, and manufacturing techniques based on solution. The optical absorber material has been used in a novel solar cell composition ITO/TiO2/CH3NH3SnI3/NiO/Mo. To assess the device's performance, several critical parameters were investigated, including, structural layer thickness, carrier mobility, and the defect density. The numerical investigations were carried through solar capacitance simulator SCAPS-1D. By using calculations, Perovskite (CH3NH3SnI3) optical absorbent layer's thickness for the optimum device efficiency was adjusted to 1.032μm, for electron transport layer (ETL) TiO2 the thicknesses was 0.002μm and hole transport layer (HTL) NiO (HTL) optimized thickness was adjusted to be 0.02μm. The device power conversion efficiency (PCE) was found to be 21.068%. Electrical parameters open circuit voltage (Voc), short circuit current (Jsc), Fill Factor (FF %) and quantum efficiency (QE) get influenced by variation in layers thicknesses and interface defect densities. The proposed composition has been thoroughly investigated, and the optimized device performance has been comprehensively analyzed in this study. Current investigations may help to design and manufacture the environmentally acceptable, non-toxic, and efficient solar cells.

Improved mechanical performance and forming accuracy of ZrO2 fixed partial denture based on the digital light processing technology

Fixed partial dentures are the primary treatment for dentition defects. Digital light processing (DLP) 3D printing technology is an advanced technique with significant advantages and potential in the field of dental restoration, particularly in cases requiring high precision and personalization. However, challenges persist in printing fixed partial dentures that meet the strength requirements for clinical applications. In this study, we aimed to optimize printing parameters, including exposure time and layer thickness, to enhance dimensional accuracy, reduce warpage, and improve the surface quality of the samples. Additionally, we focused on the rheological and curing properties of the paste. The optimal combination of printing parameters was found to be 5 s of exposure time and 50 μm layer thickness, achieving superior dimensional accuracy, reduced warpage, and improved surface quality. For a slurry with 40% solid content, the dispersant KOS 110 demonstrated the best shear thinning effect, with an optimal addition of 2%. Notably, the Vickers hardness, flexural strength, and fracture toughness of the ZrO2 fixed partial dentures were 13.52 ± 0.21 GPa, 940 ± 20 MPa, and 6.92 ± 0.25 MPa·m1/2, respectively, which surpasses that of human enamel (4 GPa) and is comparable to CAD/CAM ZrO2 (900–1200 MPa). This study demonstrates that DLP technology can be effectively used to fabricate ZrO2 personalized complex fixed partial dentures with excellent mechanical properties and high precision, offering broad application prospects in stomatology.

Tailored microstructure in laser-based powder bed fusion of IN718 through novel beam shaping technology

Inconel 718, processed by Laser-based Powder Bed Fusion of Metals (PBF-LB/M), exhibits epitaxial dendrite growth, leading to an anisotropic columnar microstructure. While columnar microstructures offer creep resistance, equiaxed microstructures provide more balanced mechanical properties. Understanding how to tailor the as-built microstructure in the PBF-LB/M process remains a persistent challenge. Recent advancements in beam shaping offer solutions for customizing heat flow direction in the PBF-LB/M process and tailoring the as-built microstructure. This research aims to systematically study how the laser beam shape affects anisotropy in the as-built microstructure and tensile mechanical properties. By using an inverse calculated beam shape, called as chair-shaped, the texture strength represented by J-index was reduced from 4.6 (generated by a ring-shaped beam profile with the same beam intensity and laser process parameters) to 1.37. The study prioritizes high productivity, with a building rate of 16 mm3/s (80 μm layer thickness) across chosen process parameters compared to state-of-the-art with a build rate of 4.2 mm3/s (40 μm layer thickness). The findings indicate that rotational asymmetric laser beam profiles with a relative beam diameter of 400 μm significantly enhance productivity by broadening the process window. These profiles also have a profound impact on the microstructure and tensile properties compared to ring-shaped and core-ring laser beam profiles. The new microstructure features a notable reduction in grain size, elongation, and texture index, producing mechanical properties that are comparable to those of an isotropic microstructure.

Toward mechanical recyclability of high barrier food packaging films through filler incorporation on the EVOH layer

AbstractTo preserve food from moisture and oxygen, polymers, such as ethylene vinyl alcohol (EVOH) are used in multilayer structures to provide oxygen barrier, while low‐density polyethylene (LDPE) is used for a water vapor barrier. While this material combination is functionally ideal, it may not comply with the new packaging recycling guidelines. Some European markets have implemented rules that limit the weight percentage of EVOH in LDPE films. One way to increase recyclability is by reducing the amount of EVOH in the film structure while maintaining the packaging's oxygen barrier properties. To achieve this, it is necessary to improve the barrier properties of EVOH. With this objective in mind, this study evaluated the incorporation of nanoclays (NC), cellulose microcrystals (MCC), silicon dioxide nanoparticles (SiO2), and cellulose nanocrystals (CNC) into an EVOH matrix. The results indicate that NC and MCC facilitate a stable blown film extrusion process and have a better dispersion in the EVOH matrix. Based on this finding, three‐layer films (with an ABA configuration) consisting of LDPE (A) and EVOH (7 μm layer) with 0.5 or 1 wt.% MCC or NC (B) were produced to protect the EVOH from moisture and enable blown film processing. The oxygen transmission rate (OTR) values were lowest for 0.5 wt.% NC and 1 wt.% MCC incorporation. Although the films with micro and nanoparticles had increased haze, this did not affect the visibility of the packaged food.

Effect of Implant Analog Design and Additively Manufactured Casts' Printing Layer Thickness on the Linear and Angular Accuracy of Analogs for Direct Digital Workflow: An In Vitro Study.

To evaluate how implant analog design and printing layer thickness affect the linear and angular accuracy of implant analogs in additively manufactured casts, comparing with conventional implant analogs in stone casts. A reference cobalt chromium mandibular model with a single implant was digitized with an industrial optical scanner and scan bodies compatible with a pressure/friction fit (S) or a screw-retained (N) implant analog for direct digital workflow. These scans were used to fabricate casts with 50 μm (S-50 and N-50) and 100 μm (S-100 and N-100) layer thickness (n&#61;10). Ten stone casts were made after single-step closed-tray polyvinylsiloxane impressions of the model (CNV). All casts were digitized with the same metal scan body and scanner used to digitize the master model, and these scans were superimposed over the scan of the master model to measure the linear (x, y, and z-axes) and angular (XY and YZ planes) deviations (Geomagic Control X). The precision of measured deviations was defined with the average deviation values. Generalized linear model analysis was used to compare the deviations within implant analogs for direct digital workflow, while 1-way analysis of variance and Dunnett's test were used to compare these analogs and conventional analogs (α &#61; .05) Results. The analog design affected the linear deviations (y-axis), while the interaction between the analog design and the layer thickness, and the analog design affected the angular deviations (XY plane, P ≤ .030). S analogs had lower linear and angular deviations than N analogs, and S-50 led to lower angular deviations than N-50 (P ≤ .030). CNV led to higher linear accuracy (y-axis) than N-50, N-100, and S-100 and led to lower angular deviations than all test groups (XY plane) (P ≤ .025). The analogs in S-50 casts had positional trueness similar to or higher than those in other test groups and their accuracy was mostly similar to those in CNV casts. Implant analogs for direct digital workflow deviated more towards lingual and gingival, and conventional analogs deviated more towards buccal, occlusal, and distal. All analogs had a tendency to tilt towards lingual and distal.

Effect of Powder Spreading Parameters on Laser Absorption Behavior and Processability of High‐Strength Aluminum Alloy Fabricated by Laser Powder Bed Fusion

Laser powder bed fusion (LPBF) of rare‐earth‐modified high‐strength aluminum alloys presents a novel approach for manufacturing complex components with enhanced structural performance, particularly in aerospace applications. This study fabricates Al–Mg–Sc–Zr specimens using various powder spreading parameters to explore their impact on laser processability. The investigation reveals that varying the powder layer thickness from 30 to 70 μm yields the smallest irradiation diameter of 135 μm at an optimal thickness of 50 μm, attributable to effective multiple reflections, high laser absorption rates, and stability. With an optimal laser power of 400 W, a scanning speed of 600 mm s−1, and a hatching spacing of 60 μm, the sample produced at 50 μm layer thickness achieves a relative density of 99.23%, a top surface roughness of 15.42 μm, and a refined grain size of 1.67 μm. Following aging at 325 °C for 4 h, this sample exhibits a tensile strength of 518 MPa and an elongation of 15.6%. The findings establish a theoretical basis for controlling the morphology and properties of high‐strength aluminum alloys in laser additive manufacturing.

КИНЕТИКА РОСТА ДИФФУЗИОННЫХ ПРОСЛОЕК В СКМ 20880+АД1+ВТ1-0

It is shown that the diffusion zone at the interlayer boundary of steel 20880 + aluminum AD1 consists of two layers: the Fe2Al5 intermetallic compound located on the steel side and constituting the main part of the diffusion zone, and a thin (up to 10 μm) layer of the FeAl3 intermetallic compound on the aluminum side. Microhardness of the diffusion zone ~ 12 GPa. It has been established that the intensity of growth of the diffusion zone at the interlayer boundary of aluminum AD1 + titanium VT1-0 with the phase composition TiAl3 is almost one and a half times lower than at the interlayer boundary of steel 20880 + aluminum AD1. Its microhardness is ~5 GPa.

Anisotropic microstructure and tensile property of laser powder bed fusion fabricated Al–Mn–Mg–Sc–Zr alloy built at different layer thickness

Laser powder bed fusion (LPBF) fabricated Al–Mn–Mg-Sc-Zr alloy generally possesses a bi-modal microstructure of columnar grains and equiaxed grains. Such an anisotropic microstructure would introduce varied tensile performance in different orientations. To date, few study on the microstructure and tensile property anisotropy have been reported for LPBF fabricated Al–Mn–Mg-Sc-Zr alloys built at different layer thicknesses, which limits the exploration in mechanical property optimization. In this work, the microstructure anisotropy and room-temperature tensile properties of LPBF produced and peak-aged Al–Mn–Mg-Sc-Zr alloys built at 30 and 60 μm layer thicknesses were systematically investigated by scanning electron microscope, transmission electron microscope, and tensile testing. A higher layer thickness of 60 μm resulted in coarser grains with the precipitates size remained similarly compared to the 30 μm specimens. This led to a reduced yield strength in 60 μm specimens (492–509 MPa) comparing to those in 30 μm specimens at 502 MPa–510 MPa. In addition, the existence of columnar grains within melt pools contributed to a larger effective slip length in the vertical direction than that in the horizontal orientation. Such difference in effective slip length in the loading direction contributed to a lower strength in vertical orientations. For ductility, the slightly higher defect level in 60 μm specimens (0.58%) resulted in reduced elongations of 3%–6% compared to those of 30 μm specimens (0.10%). The ductility anisotropy was attributed to the preferential distribution of gas pores and keyhole defects at melt pool boundaries.

Comparison of mechanical properties of 3D printer resins for occlusal splints using different models of 3D printers.

Considering the development of new 3D printing technologies that use different printing techniques, further studies must be conducted to evaluate the impact of different printing systems on the mechanical properties of 3D-printed materials. This study aimed to evaluate the mechanical properties of 3D-printed materials for occlusal devices using different 3D printers and printing layer thicknesses. Ninety rectangular samples were manufactured and divided into nine groups according to the 3D printer model they were printed on (AnyCubic Mono X, Elegoo Mars 2, or FlashForge Hunter) and the layer thickness (20, 50, or 100 µm) and were subjected to superficial microhardness, flexural resistance, and elasticity modulus tests. The results were analyzed using two-way analysis of variance and Tukey's statistical tests, with a significance level of 5%. The type of 3D printer significantly affected superficial microhardness (p = 0.007). Flexural strength showed a significant interaction between the 3D printer and layer thickness (p = 0.005), with both factors independently influencing flexural strength (printer: p< 0.001, layer thickness: p< 0.001). Elasticity modulus was significantly influenced by the 3D printer type (p< 0.001) and the interaction between both factors (p = 0.004). The AnyCubic Mono X 3D printer with a 20 µm layer thickness exhibited more consistent mechanical properties than the other printers. Variations in printing systems and layer thicknesses can impact the mechanical properties of 3D-printed materials. Key words:CAD-CAM. Bruxism. Temporomandibular disorders. Mechanical tests; 3-D printing.Care Team.

Accessible melt electrowriting three-dimensional printer for fabricating high-precision scaffolds

Melt electrowriting (MEW) is an established 3D printing technology for producing high-resolution scaffolds for tissue engineering. Commercial MEW devices are expensive while having limited processing capabilities, which limits their accessibility and widespread use. Herein, we report an easy-to-assemble and inexpensive ($2000) MEW printer based on an off-the-shelf automated dispensing machine with user-friendly controls and a custom-designed MEW printhead capable of printing polymers with a melting point of up to 260 °C. Using the gold standard printable material, poly(ε-caprolactone) (PCL), this printer can deposit 3 μm diameter fibers at 50 μm spacing, demonstrating that the highest quality of scaffolds can be produced on the low-cost MEW system. Stability in printing is improved by maintaining a relative humidity of 30–35 %, ensuring nozzle conditions are optimal, and minimizing bubbles in the polymer melt. Key printing parameters such as a 3 kV applied voltage, 75 °C heating temperature, 100 kPa air pressure, and 30 G nozzle size are critical for high accuracy, achieving 100 μm fiber spacing and layer stacking up to 30 layers without fiber breakage. The printer effectively creates complex scaffold geometries, showcasing its precision and suitability for advanced tissue engineering applications. Overall, this study promotes low-cost MEW technology by establishing a guideline on building an accessible but capable MEW printer and providing a crucial experimental foundation toward achieving high-accuracy scaffolds.

Influence of layer thickness and exposure on mechanical properties of additively manufactured polymer-derived SiOC ceramics

One significant hurdle in additively manufacturing polymer-derived ceramics lies in reconciling the lower mechanical properties of additively manufactured parts compared to traditionally manufactured ceramics and PDCs. Here, a methodology is presented for evaluating the influence of layer thickness and exposure on polymer-derived ceramics within the constraints of commercially available software and hardware. Maximizing exposure within printable limitation of DLP processes, produced green bodies with the highest conversion, and resulted in improved pyrolysis outcomes, manufacturability, and most importantly ceramic strengths comparable to traditionally manufactured SiOC PDCs. Decreasing layer thickness and increasing total dwell time had a dramatic impact on mechanical properties, increasing flexural strength by more than 6x from 18 MPa at 100 μm layer thickness to 111 MPa at 10 μm layer thickness. Density of resultant ceramic also increased from 1.62 ± 0.03 g/cc to 2.3 ± 0.05 g/cc. This represented a large increase in mechanical strengths of PDCs produced via DLP in literature.

Comparison of Young’s Modulus determination from Ultrasonic Testing and Three-Point Bending Testing

This study investigates the comparison of Young’s modulus value from ultrasonic testing and three-point bending testing. Five specimens from ABS material were created using FDM 3D printer with parameters of 200 μm layer thickness, solid print strength, and cross print pattern. Five specimens from stainless steel 316 were fabricated from conventional plate using waterjet cutting machine. Ultrasonic tests were done on each sample from ABS and stainless steel 316 by following ASTM A578. The three-point bending experiments of ABS and stainless steel 316 specimens were following ASTM D790, and ASTM E290, respectively. Ultrasonic testing and three-point bending testing were done on both materials to find the Young’s Modulus values. The results obtained from both experiments were compared to each other as well as to a standard value. The results show that Young’s modulus values from ultrasonic testing are more comparable to the standard value than that from three-point bending testing. These are due to build orientation of ABS, and grain size of stainless steel 316 which have some effect on Young’s Modulus values.

Enhanced strength and toughness in TC4-(GNPs/TC4) composites via heterogeneous multi-scale lamination design

Simultaneously achieving high strength and toughness for Ti alloys or Ti matrix composites is highly desirable but remains a great challenge. The present study reports a heterogeneous multi-scale laminated (HML) TC4-(GNPs/TC4) composites fabricated by field assisted sintering (FAST) and hot rolling (HR). The alternating combination of GNPs/TC4 layers and TC4 layers formed the primary laminated architecture. Within the GNPs/TC4 layer, the secondary laminated architecture was constructed through the parallel distribution of GNPs. No interface delamination was observed. In particular, the as-designed composites with 1:1 thickness ratio and 250 μm layer thickness exhibited the enhanced strength without sacrifice in ductility. In-situ tensile tests revealed that the soft layer in the primary laminated architecture possessing a high strain-bearing capacity, deflected and blunted the microcracks originated from the hard layer. Moreover, the secondary laminated architecture preferred to transform the two-dimensional cracks into three-dimensional cracks, thereby effectively increasing the crack propagation path. The synergistic effect of these mechanisms noticeably enhanced the toughness of the composites. Together they act in concert to render outstanding mechanical performance. This study highlights a simple and feasible route towards well balance between strength and ductility in Ti matrix composites, and informative for achieving high-performance in GNPs/Ti system.

Slip and stress in block-in-matrix shear zones: 1. microstructure and mineralogy of a serpentine-filled dilational jog

We document the structural setting, microstructure, and mineralogy of a crack-seal-type dilational jog that developed in the stepover between two faults cutting through a phacoid of massive serpentinite, itself embedded within a serpentinite shear zone at the base of the Dun Mountain Ophiolite, New Zealand. Our outcrop and microstructural measurements allow us to constrain the boundary conditions for a numerical model (part 2) that quantitatively explores the relationships between stress, fault slip, and incremental cracking in block-in-matrix shear zones. The dilational jog is c. 3 cm wide and contains hundreds of crack-seal bands, each c. 20–30 μm wide. Internally, the jog comprises two mineralogically distinct crack-seal domains: serpentine-only domains and serpentine-andradite garnet domains. Additionally, individual crack-seal bands have a double-layer structure: in serpentine-only domains each band comprises a thin (<2 μm) layer of chrysotile and a thicker layer (c. 25 μm) of polygonal serpentine/lizardite, whereas each band in serpentine + andradite domains comprises a thinner (c. 5 μm) layer of microcrystalline andradite and a thicker layer (c. 15 μm) of polygonal serpentine/lizardite. Micro-CT analysis shows that the serpentine + andradite domains have conic or ellipsoidal shapes with long axes subparallel to the inferred jog opening direction, and that andradite is smeared along micro-transform surfaces inside the jog. Our conceptual microstructural model invokes jog formation during progressive serpentinization of the host rock. Incremental crack opening along the jog-wall rock interface promotes relatively rapid initial precipitation of chrysotile or andradite at high fluid:rock ratios. As cracks fill and pressure re-equilibrates, relatively slow growth of polygonal serpentine/lizardite is favoured until the cracks are sealed and the cycle repeats. Our observations suggest that the precipitation of andradite (instead of chrysotile) was controlled both by structural boundaries within the jog (e.g., micro-transform surfaces) and by local element transport (e.g., Ca from serpentinizing clinopyroxene grains in the host rocks) to patches of the crack wall.

Development and Validation of HPTLC for the Determination of Gefitinib HCl in Tablet Dosage Form

A simple, high-performance thin-layer chromatography (HPTLC) method of gefitinib HCl in pharmaceutical formulation was developed. Separation was done on TLC aluminum plates precoated by silica gel 60GF254 (20 × 20 cm) with 200 μm layer depth. With UV detection set to 254nm, chromatography was conceded out by the mobile phase of dichloromethane and methanol (9:1, v/v). Linearity was found to range of 50 to 300 ng/spot and, the correlation coefficient was found to be 0.99 and the Rf value was found to be 0.46. The system’s suitability was considered to ascertain the performance of ascertaining quality performance of the developed chromatographic method. The method’s accuracy, precision, and specificity were all verified against the International Council of Harmonization (ICH) standards. Application of the approach to the determination of gefitinib in tablet form was successful.

Microstructure, compressive performance and wear resistance of pure molybdenum additively manufactured via laser powder bed fusion

Pure molybdenum (Mo) additively manufactured via laser powder bed fusion is challenging due to its high laser reflectivity and sensitivity to cracking. To achieve crack-free pure Mo alloy and enhance production efficiency, this study employs a high-power (350 W) printing process with a layer thickness of 30 μm, resulting in the successful fabrication of pure Mo with a relative density of 99.2%. X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) revealed that the pure Mo specimens prepared by LPBF process exhibited different preferential grain orientations and lattice distortions in various building directions, with higher texture strength on the XOZ plane and greater lattice distortion on the XOY plane. The hardness of the pure Mo specimens reached 208 HV, with uniaxial compressive strength and elongation at 535 MPa and 20.9%, respectively, surpassing existing literature values by 37.2% and 8.0%. Furthermore, the dry friction behavior and mechanism of LPBF-manufactured pure molybdenum were investigated for the first time and compared to traditional powder metallurgy. Consequently, this research offers valuable insights for manufacturing crack-free LPBF pure molybdenum components with 30 μm layer thickness, boasting superior mechanical and wear resistance.