Powder Metallurgy and Metal Ceramics最新文献

{"title":"Thermodynamic Assessment of the Glass-Forming Cu–Ti–Hf System","authors":"M. A. Turchanin,&nbsp;P. G. Agraval,&nbsp;G. O. Vodopyanova","doi":"10.1007/s11106-023-00358-5","DOIUrl":"10.1007/s11106-023-00358-5","url":null,"abstract":"<div><div><p>In the framework of the CALPHAD method, the thermodynamic assessment of the Cu–Ti–Hf system has been performed for the first time. This assessment considers the existence of homogeneity regions for Cu₃Ti₂, Cu₄Ti₃, CuTi, Cu₅Hf, Cu₅₁Hf₁₄, and Cu₁₀Hf₇ compounds and the formation of a continuous solid solution of Cu(Ti, Hf)₂ (γ-phase) in the ternary system. The thermodynamic assessments of the boundary binary systems and data on phase transformations and mixing enthalpy of melts in the ternary system became the basis for calculations. The Compound Energy Formalism was used to model the thermodynamic properties of intermetallic compounds with a homogeneity region. The associated solution model was used to describe the complex temperature dependence of the thermodynamic properties of melts from the temperature at which equilibrium melts exist to the glass-formation temperature. Upon the calculations, isothermal sections, vertical sections, projections of the liquidus and solidus surfaces, and reaction scheme of the phase diagram were presented. The liquid phase participates in eleven four-phase invariant reactions occurring in the temperature range 1138–1541 K. The diagrams of metastable phase transformations involving supercooled Cu–Ti–Hf melts and boundary solid solutions based on pure components were calculated. It is shown that supercooled melts in wide concentration ranges are thermodynamically stable in relation to boundary solid solutions based on pure components. The concentration region of glass formation for Cu–Ti–Hf melts by liquid quenching, predicted by the relative position of the <span>({T}_{0}^{L/phi })</span> and <span>({x}_{0}^{L/phi })</span> lines, is <i>x</i>_<i>Cu</i> ≈ 0.16–0.80.</p></div></div>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"61 11-12","pages":"708 - 726"},"PeriodicalIF":1.0,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4673796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temperature Dependences of the Mechanical Properties of Microlayer Ti/TiAl3 Composites Under Cyclic Loading","authors":"Yu. F. Lugovskoy,&nbsp;V. A. Nazarenko,&nbsp;V. A. Zorin,&nbsp;S. A. Spiridonov,&nbsp;V. G. Borovik","doi":"10.1007/s11106-023-00360-x","DOIUrl":"10.1007/s11106-023-00360-x","url":null,"abstract":"<div><div><p>The paper examines three microlayer Ti/TiAl₃ materials of initial Ti–Al composition, which were produced through reactive sintering and rolling of packets consisting of alternating titanium and aluminum ribbons of varying thickness at 600, 700, and 770°C. Young’s modulus of these materials was determined under longitudinal vibrations at room temperature with a frequency of about 45 kHz and under resonant bending vibrations at high temperatures ranging from 20 to 820°C with a frequency a hundred times lower. The temperature dependences of the elastic modulus E for the microlayer materials exhibited slopes between those of the dependences for titanium and the well- known VT25U alloy. The Ti/TiAl₃ materials were heated and held at 700°C to result in a material with stable E values, surpassing those of the VT25U alloy at temperatures up to 700°C. The dependences of stresses in the samples on the relative power of the test installation were determined at constant temperatures of 650 and 700°C for the microlayer Ti/TiAl₃ and VT25U materials. The microlayer materials dissipated a significantly larger portion of mechanical vibration energy than the heat-resistant VT25U material. The difference in the fatigue resistance mechanisms for the microlayer and isotropic materials at high temperatures is not solely attributed to their distinct temperature dependences of Young’s modulus at atomic interaction levels. The difference primarily arises from the variation in temperature-dependent cyclic strains associated with dislocations at microstructural and macrostructural levels. A fatigue crack is shown to delaminate the material in the middle of the intermetallic layers.</p></div></div>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"61 11-12","pages":"736 - 747"},"PeriodicalIF":1.0,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4596717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sintering of Ferromagnetic Materials at Lower Temperatures in Hydrogen. II. Nd–Fe–B Alloys","authors":"I. I. Bulyk,&nbsp;I. V. Borukh","doi":"10.1007/s11106-023-00354-9","DOIUrl":"10.1007/s11106-023-00354-9","url":null,"abstract":"<div><div><p>The use of the hydrogenation and disproportionation (HD) and desorption and recombination (DR) route (HDDR) for sintering Nd₂Fe₁₄B-based ferromagnetic alloys, such as Nd_11.7Fe_81.1Zr_1.2B₆ and Nd₁₆Fe_73.9Zr_2.1B₈, was studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The dependence between the production conditions—grinding of the alloys into powders, compaction pressure of the powders, hydrogen pressure and temperature at the first stage of sintering in hydrogen (HD), and temperature at the second stage of sintering in vacuum (DR)—and the porosity and microstructural particle size of the sintered materials was evaluated. The powders were ground in hydrogen in a planetary-ball mill at 200 rpm for 1 h and compacted at 2, 5, and 6 t/cm². The first sintering stage was carried out at a hydrogen pressure of 0.05 MPa and a temperature of 760°C, and the second stage at 850 and 950°C. The powders were found to sinter at the first stage. The porosity of the sintered materials decreased with increasing compaction pressure. The grain size of the ferromagnetic Nd_11.7Fe_81.1Zr_1.2B₆ phase in the sintered materials ranged from 100 to 300 nm. The physical mechanism behind the reduction in the sintering temperature was attributed to an increase in the diffusion rate of alloy components resulting from hydrogen-induced phase transformations, such as disproportionation and recombination, and to the presence of a hydrogen solid solution at both stages of the process, HD and DR. A very important aspect of this research is that the powders were sintered under low hydrogen pressure required to produce magnetically anisotropic materials. Problematic aspects of the properties shown by the sintered materials, particularly microstructural heterogeneity, were analyzed, and approaches to their solution, through homogenizing the particle size of the powders and optimizing the HDDR parameters (hydrogen pressure, temperature, reaction time), were proposed. The process advantages of the new sintering method compared to similar techniques included the temperature lower by more than 100°C, the potential for producing nanostructured anisotropic materials, and the use of technically simpler and cheaper sintering furnaces.</p></div></div>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"61 11-12","pages":"657 - 669"},"PeriodicalIF":1.0,"publicationDate":"2023-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4601409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Densification Dynamics of WC–36 wt.% Cu Cermet During Impact Assisted Sintering in Vacuum","authors":"M. S. Kovalchenko,&nbsp;A. V. Laptiev,&nbsp;O. I. Tolochyn","doi":"10.1007/s11106-023-00353-w","DOIUrl":"10.1007/s11106-023-00353-w","url":null,"abstract":"<div><div><p>The densification of a fine-grained tungsten carbide cermet containing 36 wt.% copper binder during impact assisted sintering in a vacuum at thermodynamic temperatures of 1023, 1123, and 1223 K with an initial impact velocity of 6.4 m/s was studied. Based on the experimental data and calculated elastic properties of the samples and the impact machine, computational modeling of the densification dynamics with a trial and error method was carried out using a third-order dynamic system in combination with the rheological model of Maxwell’s viscoelastic body, and as a result previously unknown values of shear viscosity for material cermet matrices were obtained. The time dependences of force, compression, velocity, and acceleration of the system, as well as shrinkage, root-mean-square stress, and strain rate, of the cermet samples during impact assisted sintering were determined. The calculated phase trajectory of the dynamic system movement showed that the initial kinetic energy of the impact was not completely exhausted for the irreversible densification of the cermet samples. Part of the energy dissipated in the environment after the rebound of the machine’s impact parts. At the initial stage, the system exhibited nonperiodic (atemporal) damping during its movement at high ratios between the system’s stiffness and the cermet samples’ viscous resistance. As the ratio decreased, the movement transformed into damping oscillations. The work of densification and the thermomechanical effect, which significantly increased the temperature of porous samples, were evaluated. The estimated activation energy of the viscous flow for the porous cermet matrix was 0.34 eV or 33 kJ/mol that indicated the dislocation mechanism of sintering. The samples produced by impact assisted sintering showed significantly higher strength values compared to pressureless sintered samples at a higher temperature.</p></div></div>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"61 11-12","pages":"644 - 656"},"PeriodicalIF":1.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4565921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Influence of Strain on Texture Changes and Phase Transformations in the Quenched Ti92.5Nb5Mo2.5 Alloy","authors":"O. M. Myslyvchenko,&nbsp;Yu. M. Podrezov,&nbsp;A. A. Bondar,&nbsp;D. G. Verbylo,&nbsp;V. A. Nazarenko,&nbsp;V. M. Voblikov","doi":"10.1007/s11106-023-00361-w","DOIUrl":"10.1007/s11106-023-00361-w","url":null,"abstract":"<div><div><p>The strain-induced martensitic transformation in a medical alloy from the ternary Ti–Nb–Mo system was studied. The low-doped Ti_92.5Nb₅Mo_2.5 alloy was produced by arc remelting, followed by annealing, rolling at room temperature, reannealing, and water quenching. X-ray diffraction analysis showed that thermomechanical processing resulted in the alloy primarily consisting of orthorhombic martensite (α?) with a small amount of the β-titanium phase. Hysteresis loops were recorded in loading–unloading cycles with 1% strain increments up to a total strain of 4% under compression testing, employing a precision strain gauge. Young’s modulus under loading varied from 51.2 GPa at the initial section to 39.7 GPa after a 2% residual strain. Young’s modulus remains unchanged, within 74.3 GPa, during unloading. Elastic, pseudoelastic, and plastic strains were found to significantly depend on the previous strain within the first three loading–unloading cycles. To examine the impact of higher strains (up to 23.4%) on structural rearrangements and phase transformations, the samples were compressed without a precision strain gauge. X-ray diffraction analysis revealed that only the crystalline texture of the alloy changed after compression. Strains exceeding 23.4% were achieved by rolling at room temperature. After rolling to a strain of 64%, the diffraction patterns indicated an increased amount of the β-phase, as evidenced by the (200) diffraction peak, not observed previously. The increased amount of the β-phase suggests that strain prompted the reverse martensitic transformation (α? → β).</p></div></div>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"61 11-12","pages":"748 - 753"},"PeriodicalIF":1.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4563523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Contamination in the Process of Forming a Titanium-Based Nanocrystalline Alloy Using VSM, SEM-EDS, and XRD Techniques","authors":"Abderahim Abada,&nbsp;Abderrahmane Younes","doi":"10.1007/s11106-023-00356-7","DOIUrl":"10.1007/s11106-023-00356-7","url":null,"abstract":"<div><div><p>In this study, nanocrystalline TiAlV alloys were synthesized using the mechanical alloying technique with a high-energy planetary ball mill from pure Ti, Al, and V powders. Various methods, including Vibrating Sample Magnetometry (VSM), Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM-EDS), and X-ray Diffraction (XRD), were employed to characterize the synthesized alloys and study their magnetic behavior, morphology, microstructural and structural properties, respectively. Following the XRD analysis, new phases were confirmed, and a significant reduction in crystallite size from 48.73 to 9.38 nm was observed. Moreover, an increase in lattice strain from 0.15% to approximately 0.81% was noted after 60 h of milling. The EDS analysis gave remarkable results, showing the lack of magnetic iron particles before milling. However, after milling, the EDS spectrum revealed the presence of these magnetic iron particles with varying concentrations. This important observation highlights the profound impact of the mechanical alloying process on the sample composition. It emphasizes the sensitivity of EDS analysis by detecting even subtle changes in the elementary composition of a material. A sensitive approach was employed to monitor the progression of the nanocrystalline alloy and identify any potential defects arising during the mechanical milling. A vibrating sample magnetometer was utilized to achieve this objective. This method is highly effective at capturing even subtle changes that may occur during milling, allowing for an accurate evaluation of the chemical composition and integrity of the alloy. This technique made it possible to detect the presence of magnetic particles whose magnetic properties varied from time to time, indicating a change in magnetic behavior due to the reduction in the size of these particles caused by the collision between the steel balls and the milled powder particles. The results suggest that non-destructive magnetic testing using a VSM can be used to monitor the state of the nanocrystalline alloy.</p></div></div>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"61 11-12","pages":"691 - 698"},"PeriodicalIF":1.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4564485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Use of Carbon Nanostructures in Various 3D Printing Techniques","authors":"Ol. D. Zolotarenko,&nbsp;E. P. Rudakova,&nbsp;An. D. Zolotarenko,&nbsp;N. Y. Akhanova,&nbsp;M. N. Ualkhanova,&nbsp;D. V. Schur,&nbsp;M. T. Gabdullin,&nbsp;T. V. Myronenko,&nbsp;A. D. Zolotarenko,&nbsp;M. V. Chymbai,&nbsp;I. V. Zagorulko,&nbsp;O. A. Kamenetska,&nbsp;M. Yu. Smirnova-Zamkova","doi":"10.1007/s11106-023-00355-8","DOIUrl":"10.1007/s11106-023-00355-8","url":null,"abstract":"<div><div><p>A scheme for the full cycle of developing 3D products containing carbon nanostructures (CNSs) was developed. The scheme takes into account the state of initial carbon for the synthesis of CNSs and involves the preparation of CNSs for various 3D printing techniques (FDM, CJP, SLA, SLS) with post-processing of the printed 3D products. The developed cycle allows for the transformation of graphite or other carbon-containing materials into functional 3D products using a 3D printer. The 3D development cycle consists of three stages: Stage I is intended to select the starting material and method for CNS synthesis, Stage II involves preparation of CNSs as a consumable for 3D printing, and Stage III includes printing of a 3D product followed by post-processing. Each stage is described in detail and tested for each 3D printing technique (FDM, CJP, SLA, SLS). The entire range of CNSs (fullerenes and fullerene-like nanostructures, graphenes, carbon nanotubes (CNTs), carbon nanofibers (CNFs), nanocomposites, etc.) and their synthesis employing three methods (plasmaassisted chemical synthesis in gaseous and liquid environments and pyrolytic synthesis) in the 3D printing cycle were analyzed. The advantages and disadvantages of the considered 3D printing processes were addressed, and results of the comparison were summarized in a table. Materials for 3D printing and development of associated composites containing soluble and insoluble CNSs were studied. Methods for processing CNSs and preparing CNS-based composites prior to their use in various 3D printing processes were developed. The post-processing results for 3D products prepared with the FDM, CJP, SLA, and SLS 3D printing processes were provided.</p></div></div>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"61 11-12","pages":"670 - 690"},"PeriodicalIF":1.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4565920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of the ZrO2-Based Solid Solution on the Low-Temperature Phase Stability of ZrO2−Y2O3−CeO2 Materials","authors":"I. O. Marek,&nbsp;O. V. Dudnik,&nbsp;S. A. Korniy,&nbsp;V. P. Redko,&nbsp;O. K. Ruban","doi":"10.1007/s11106-023-00359-4","DOIUrl":"10.1007/s11106-023-00359-4","url":null,"abstract":"<div><div><p>The low-temperature phase stability of 97 mol.% ZrO₂–3 mol.% Y₂O₃, 95 mol.% ZrO₂–3 mol.% Y₂O₃–2 mol.% CeO₂, 92.5 mol.% ZrO₂–2.5 mol.% Y₂O₃–5 mol.% CeO₂, 90 mol.% ZrO₂–2 mol.% Y₂O₃–8 mol.% CeO₂, and 88 mol.% ZrO₂–12 mol.% CeO₂ materials in the ZrO₂–Y₂O₃–CeO₂ system was studied. The phase stability was determined through accelerated aging in hydrothermal conditions for 7 h and 14 h. The evaluation criterion was the amount of the M-ZrO₂ phase that formed in the samples when aged in hydrothermal conditions. The properties of the materials were analyzed by X-ray diffraction and electron microscopy. The T-ZrO₂ → M-ZrO₂ phase transformation occurred to varying degrees in all samples except for the 88 mol.% ZrO₂–12 mol.% CeO₂ sample after the first and second aging cycles. The smallest amount of M-ZrO₂ formed in the 90 mol.% ZrO₂–2 mol.% Y₂O₃–8 mol.% CeO₂ sample. After both aging cycles, the fracture patterns for the 90 mol.% ZrO₂–2 mol.% Y₂O₃–8 mol.% CeO₂ and 88 mol.% ZrO₂–12 mol.% CeO₂ samples did not change significantly. With the complex stabilization of zirconia by yttria and ceria, the T-ZrO₂ → M-ZrO₂ phase transformation was controlled in the aging process by the number of oxygen vacancies resulting from the presence of yttria and by the stresses induced by the presence of ceria in the solid solutions. The number of oxygen vacancies decreased as ceria content in the ZrO₂-based solid solutions increased, slowing down the rate of water diffusion and enhancing the low-temperature phase stability in the ZrO₂–Y₂O₃–CeO₂ materials. The effectiveness of using the 90 mol.% ZrO₂–2 mol.% Y₂O₃–8 mol.% CeO₂ and 88 mol.% ZrO₂–12 mol.% CeO₂ composites for the microstructural design of medical materials with increased resistance to low-temperature degradation in humid environments was shown.</p></div></div>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"61 11-12","pages":"727 - 735"},"PeriodicalIF":1.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4563522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Studying the Compressibility of Ground Metallurgical Raw Materials","authors":"A. Yu. Khudyakov,&nbsp;S. V. Vashchenko,&nbsp;K. V. Baiul,&nbsp;Yu. S. Semenov","doi":"10.1007/s11106-023-00362-9","DOIUrl":"10.1007/s11106-023-00362-9","url":null,"abstract":"<div><div><p>The pelletizing of fine-grained mineral raw materials for ferrous metallurgy is studied. Relationships between the compressibility of metallurgical charges and the nature of the raw materials and process factors of the pelletizing process were studied in laboratory conditions. A new measure, such as the compressibility of ground materials, was introduced to quantify and compare compression performances. A mathematical description of the relationships between the compression coefficient and the following factors was formulated through nonlinear regression analysis and experiment design theory methods: the plasticizer content (varying from 0 to 50%), moisture content of the charge (from 0 to 10%), hardness of the particles according to the mineralogical scale (from 2 to 6 units), dynamic viscosity of the binder (from 1 to 657 mPa · sec), amount of the carbon-containing component (from 10 to 90%), and particle sizes of the iron- and carbon-containing components in the charge (from 1 to 4 mm). The compaction pressure range was limited to 220 MPa. Three mathematical models were developed to establish relationships between the charge compressibility and the specified factors as polynomial dependencies and as a Lorentz function. The quality of the models was verified using standard statistical indicators, including the Cochran and Fisher tests and the average relative error. Analysis of the models involved the solution of relevant optimization problems. Extremes of the functions for metallurgical charges were identified and process recommendations were made. The results have practical implications for improving the compressibility of charges from mineral raw materials and developing optimal pelletizing methods.</p></div></div>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"61 11-12","pages":"754 - 765"},"PeriodicalIF":1.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4563524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Study of Nickel-Based Super-Alloy Powders Atomized by Argon and Nitrogen","authors":"Weijie Zhong,&nbsp;Hanlin Peng,&nbsp;Dongling Jiao,&nbsp;Wanqi Qiu,&nbsp;Zhongwu Liu,&nbsp;Wenyong Xu,&nbsp;Zhou Li,&nbsp;Guoqing Zhang","doi":"10.1007/s11106-023-00352-x","DOIUrl":"10.1007/s11106-023-00352-x","url":null,"abstract":"<div><div><p>This work allowed the study and comparison of the cooling rate, surface morphology, and microstructure of nickel-based super-alloy powders produced by the atomization of argon and nitrogen. The results show that the principal phase in argon and nitrogen atomized powders has an FCC structured γ-phase with γ′-strengthening phase. X-ray diffraction detected no apparent nitride or oxide on the powder surface. The interplanar spacing and lattice constant of γ-phase increase as the powder size decreases. Nitrogen- and argon-atomized powders are spherical, but argon- atomized powders have higher sphericity and smoother surfaces. Atomization by argon has produced a small number of satellite particles, whereas atomized nitrogen powders have more split particles. The proportion of special-shaped powder decreases with the decreasing powder particle size. The super-alloy powder with high sphericity can be effectively obtained by controlling the particle size. Because of the higher coefficient of thermal expansion, the trough of argon-atomized powders is higher than that of nitrogen-atomized powders with the same particle size. As the powder particle size decreases, the hollowness of the powders declines for both powders, with the argon- atomized powder falling more quickly. The cooling rate of melted alloy droplets has an essential effect on the surface characteristics of the powder. The dendrite morphology of argon-atomized powders is more evident than that of nitrogen-atomized powders. As the powder particle size decreases, the radial dendrites gradually disappear, with dendrites and cellular crystals dominating the powder surface. The cooling rate of the powder is calculated based on the surface secondary dendrite arm spacing. It is found that argon-atomized powders exhibit cooling rates from 2.09 × 10⁴ K ? s^–1 to 1.26 ? 10⁵ K ? s^–1, while nitrogen-atomized powders show higher cooling rates in the range between 2.71 ? 10⁴ K ? s^–1 and 1.86 ? 10⁵ K · s^–1. Because of the higher cooling rate, nitrogen- atomized powders have a lower secondary dendrite arm spacing than argon-atomized powders with similar particle sizes.</p></div></div>","PeriodicalId":742,"journal":{"name":"Powder Metallurgy and Metal Ceramics","volume":"61 11-12","pages":"633 - 643"},"PeriodicalIF":1.0,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4563538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}