| 1. |
- Arya, Pradyumn Kumar, et al.
(författare)
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Development of high strength and lightweight Ti6Al4V5Cr alloy : Microstructure and mechanical characteristics
- 2024
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Ingår i: Journal of Materials Research and Technology. - : Elsevier Editora Ltda. - 2238-7854 .- 2214-0697. ; 28, s. 3526-3540
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Tidskriftsartikel (refereegranskat)abstract
- This article explains development of high strength and lightweight Ti6Al4V5Cr alloy by μ-plasma powder additive manufacturing (μ-PPAM) process for automotive, aerospace, military, dies and moulds, and other similar applications. Microstructure, formation of phases, porosity, microhardness, tensile properties, abrasion resistance, and fracture toughness of multi-layer deposition of Ti6Al4V5Cr alloy are studied and compared with Ti6Al4V alloy. Results reveal that the presence of chromium in Ti6Al4V5Cr alloy refined the grains of its β-Ti and α-Ti phases, increased volume % of β-Ti phase, and promoted formation of its equiaxed grains. It also increased tensile strength, microhardness, abrasion resistance, and fracture toughness of Ti6Al4V5Cr alloy. It enhanced solid solution strengthening and formed higher hardness imparting intermetallic Cr2Ti phase and changed fracture mode to mixed ductile and brittle mode with larger size dimples, cleavage facets, and micropores. But it decreased formation temperature of β-Ti phase and % elongation as compared to Ti6Al4V alloy. Chromium and vanadium content in β-Ti phase of Ti6Al4V5Cr alloy is 7 % and 2.1 % more than its α-Ti phase. This study demonstrates that inclusion of limited amount of chromium content to Ti6Al4V5Cr alloy by μ-PPAM process is very beneficial to enhance microstructure, mechanical properties, crack propagation resistance, and abrasive wear resistance of the Ti6Al4V5Cr alloy. It makes Ti6Al4V5Cr alloy very useful in many commercial applications that require higher strength than Ti6Al4V alloy along with lightweight requirement.
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| 2. |
- Ciurans Oset, Marina, 1993-, et al.
(författare)
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Role of the microstructure and the residual strains on the mechanical properties of cast tungsten carbide produced by different methods
- 2024
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Ingår i: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854 .- 2214-0697. ; 30, s. 3640-3649
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Tidskriftsartikel (refereegranskat)abstract
- Cast tungsten carbide (CTC) is a biphasic, pearlitic-like structure composed of WC lamellae in a matrix of W2C. Besides excellent flowability, spherical CTC powders exhibit superior hardness and wear resistance. Nevertheless, the available literature generally fails to explain the physical mechanisms behind such a phenomenon. In the present work, the microstructure and the mechanical properties of the novel centrifugally-atomized spherical CTC have been extensively investigated. This material exhibited an extremely fine microstructure, with WC lamellae of 27-29 nm in thickness and bulk lattice strains of 1.0-1.4 %, resulting in a microindentation hardness of 31.4 ± 1.6 GPa. The results of this study clearly show that centrifugally-atomized CTC is mechanically superior to both spheroidized CTC and conventional cast-and-crushed CTC. In addition, the effect of a series of heat treatments on the bulk fracture toughness and the fatigue life of entire CTC particles was also investigated. The reduction of residual stresses in the bulk of particles upon annealing dramatically increased the indentation fracture toughness, whereas the bulk microindentation hardness remained essentially unaffected. Regarding the fatigue life of entire particles under uniaxial cyclic compressive loading, local phase transformation phenomena at the surface of the particles upon heat treatment were concluded to play the most critical role. Indeed, the cumulative fatigue damage was minimized in surface-carburized CTC powders, where compressive stresses were induced at the outermost surface.
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| 3. |
- Majeed, Samadar S., et al.
(författare)
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Development of ultra-lightweight foamed concrete modified with silicon dioxide (SiO2) nanoparticles: Appraisal of transport, mechanical, thermal, and microstructural properties
- 2024
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Ingår i: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854 .- 2214-0697. ; 30, s. 3308-3327
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Tidskriftsartikel (refereegranskat)abstract
- Over the last few decades, researchers have devoted significant consideration to the use of nanoscale elements in concrete. Silicon dioxide nanoparticles (SDNs) have been a popular subject of study among the several types of nanoparticles. This article describes the findings of a laboratory investigation that examined the properties of ultra-lightweight foamed concrete (ULFC) including different proportions of SDNs. Wide range of the properties was evaluated specifically the slump flow, density, consistency, flexural strength, modulus of elasticity, compressive strength, split tensile strength, thermal properties, porosity, water absorption, sorptivity, intrinsic air permeability, and chloride diffusion. Additionally, the scanning electron microscopy (SEM) and pore distributions analyses of different mixes were done. Results confirmed a noticeable increase in the mechanical properties of ULFC, with respective improvements in the 28-day compressive, split tensile, and flexural strengths of up to 70.49%, 76.19%, and 51.51%, respectively, at 1.5% of the SDNs inclusion. However, further increases in the SDNs percentage did not result in remarkable enhancements. As the SDN percentage increased from 1.5% to 2.5%, the ULFC’s sorptivity, porosity, water absorption, intrinsic air permeability, and chloride diffusion showed substantial improvements. When compared to the control sample, ULFC with SDNs demonstrated higher thermal conductivity values. The reason for this occurrence was determined to be the smaller pore size observed in the ULFC specimens containing SDNs. A great adjustment in the distribution of pore diameters was witnessed in the ULFC mixes when the percentages of SDNs were adjusted. The ULFC specimens, which included SDNs at the percentages of 0.5%, 1.0%, and 1.5%, indicated a reduction in the total number of large voids measuring 500 nm or more, compared to the control ULFC specimen. The findings of this study highlight the potential benefits of incorporating SDNs into ULFC, which may improve its overall properties.
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| 4. |
- Zhang, Qing, et al.
(författare)
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On the application of reduced pressure test for the prediction of ductility of 46000 alloy : Role of pore's morphology and distribution
- 2024
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Ingår i: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854 .- 2214-0697. ; 31, s. 927-934
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Tidskriftsartikel (refereegranskat)abstract
- Bifilms have been proposed to be critical for forming casting defects. The reduced pressure test (RPT) and bifilm index (BI) have been widely studied and used in industry for melt quality assessment. However, the BI remains challenged in predicting the mechanical properties. This work investigated the usage of RPT for elongation prediction by analyzing the melt in two foundries. The results showed that the BI could be valid when the bifilms exist as fully inflated pores. In reality, bifilms present as pores with various morphology and distribution, generating local stress concentrations under tension. Consequently, the parameter areaeff, which considers the pores’ morphology and distribution, was proposed, and the resultant f eff showed a good correlation with the elongation of the castings. These results guide the foundry to predict the elongation of the final castings and give directions for further research on the bifilm defects.
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| 5. |
- Sathvik, S., et al.
(författare)
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Evaluation of asphalt binder and mixture properties utilizing fish scale powder as a biomodifier
- 2024
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Ingår i: Case Studies in Construction Materials. - : Elsevier. - 2214-5095 .- 2214-0697. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- Fish represents an abundant and underutilized waste product from the fishing industry. This study investigated the effects of incorporating fish scale powder (FSP) at various dosages (3%, 6%, 9%, and 12%) on the properties of asphalt binder and mixtures. Conventional tests, viscosity, storage stability, Fourier transform infrared spectroscopy, and multiple stress creep recovery tests were conducted on the binder. Mix design, wheel tracking, indirect tensile strength, fatigue, and ultrasonic pulse velocity tests were evaluated for the asphalt mixtures. The results showed that FSP increased the binder’s stiffness and reduced the temperature susceptibility but compromised the low-temperature performance and workability regardless of the dosages. The storage stability test results demonstrated the improved high-temperature storage stability. In the mixtures, the permanent deformation resistance enhanced with increasing the FSP content, decreasing the rut depth from 4.3 mm for the control sample to 2.9 mm at 12% FSP. The moisture damage resistance, indicated by the tensile strength ratio, increased from 90% for the control sample to 94.1% at 12% FSP. However, the fatigue life decreased from 14010 cycles for the control sample to 11190 cycles at 12% FSP. The dynamic and elastic modulus values before conditioning increased with higher FSP dosages, and this increasing trend was also observed after conditioning, signifying greater stiffness retention and moisture resistance of the asphalt mixtures containing higher amounts of FSP. Numerically, the 6–9% FSP range offered the optimum balance, improving the rutting resistance by 18% and the moisture resistance by 3.2% compared to those of the control sample, while limiting the fatigue life to 12% and maintaining the workability. Overall, FSP has potential for use as an asphalt biomodifier by transforming an environmental liability into a value-added sustainable paving material.
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| 6. |
- Alhourani, A., et al.
(författare)
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Thermal modeling of friction stir welding of thick high-density polyethylene plates
- 2024
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Ingår i: Journal of Materials Research and Technology. - : Elsevier BV. - 2238-7854. ; 28, s. 4186-4198
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Tidskriftsartikel (refereegranskat)abstract
- The process temperatures in the friction stir welding of thick polymer plates play a significant role in the joint's quality since the process is characterized by mixed solid and viscous flow states. The heat generation mechanism in each state is fundamentally different, with heat being generated by friction in the solid-state and by viscous shear flow in the viscous state. In this study, the heat generation and dissipation in the friction stir welding of 14 mm thick high-density polyethylene plates were studied numerically through solving the direct heat conduction problem. Two models of heat generation were used in the numerical solution and the effect of the pin rotational speed on the process temperatures was investigated. It was shown that the utilization of a mixed heat generation model consisting of both the solid state and the viscous shear flow considerably improves the numerical model predictions. The temperature predictions were validated through welding experiments and showed a temperature difference of 3 %. Furthermore, it was found that the welding process stabilizes at rotational speeds higher than 800 rpm, where no considerable change occurs in the volume of the viscous flow region and the welding power requirement. The numerical results based on the combined solid-viscous heat model were in good agreement with the experimental thermal histories.
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| 7. |
- de Andrade Schwerz, Claudia, 1992, et al.
(författare)
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Mechanical properties of Hastelloy X produced by laser powder bed fusion and affected by spatter redeposition
- 2024
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Ingår i: Journal of Materials Research and Technology. - : ELSEVIER. - 2238-7854. ; 29, s. 4200-4215
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Tidskriftsartikel (refereegranskat)abstract
- Defects in materials manufactured via laser powder bed fusion challenge this manufacturing process' dependability and may prevent it from being comprehensively used for structural components, particularly those intended to operate under dynamic loading conditions. This study aims to investigate the effect of spatter-driven lack of fusion on the mechanical properties of Hastelloy X, with a particular focus on fatigue performance. Mechanical test specimens were manufactured in two builds with different build rates and monitored through in-situ optical tomography. The images acquired in situ were analyzed to detect spatter redeposits to predict the defect content in the gauge section. Selected specimens were measured ex-situ using X-ray computed tomography to map the defect populations. Afterward, the specimens were tensile and fatigue tested, and their performance was analyzed based on the measured and expected defect populations. It was confirmed that a higher build rate is associated with more extensive detection of spatter redeposits in optical tomography images and lack of fusion defects. The fatigue lives of specimens manufactured at higher build rates presented higher scatter but significantly higher average, despite the more critical defect population. Surprisingly, the confirmed presence of lack of fusion defects in the gauge section of test specimens did not necessarily result in a poorer fatigue performance. It was concluded that the grain refinement obtained through the increase in nominal layer thickness has a life-prolonging effect that overrides the effects of spatter-induced lack of fusion defects.
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| 8. |
- de Andrade Schwerz, Claudia, 1992, et al.
(författare)
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Reduction of oxygen content in laser powder bed fusion process atmosphere – Effects on stochastic defect formation and mechanical properties
- 2024
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Ingår i: Journal of Materials Research and Technology. - : ELSEVIER. - 2238-7854. ; 30, s. 4667-4681
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Tidskriftsartikel (refereegranskat)abstract
- Stochastic defects in materials manufactured via laser powder bed fusion (LPBF) can severely compromise mechanical performance and are challenging to predict and detect, thus motivating the development of defect mitigation strategies. Particle oxidation is a factor well-known to generate defects by disturbing melt pool dynamics. If the particles are spatters, additional disturbances increase the likelihood of defect formation. In this study, restricting oxygen content in the process atmosphere to 50 ppm is investigated to minimize stochastic spatter-induced defects and improve the mechanical properties of Hastelloy X. Specimens were manufactured under this condition at two nominal layer thicknesses, analyzed for internal defects, and mechanically tested. Contrary to expectations, reducing the oxygen content did not prevent spatter-induced defect formation; rather, it could exacerbate the formation of more numerous and larger defects. Nevertheless, this tighter control of the process atmosphere led to significant microstructural refinement, which, when combined with sparse defects, resulted in improved fatigue performance. Despite the inherent ductility of Hastelloy X, the presence of abundant defects significantly larger than the microstructural characteristic size proved detrimental to fatigue performance. Notably, the occurrence of defects exhibited considerable variation across the build area, contributing to scatter in fatigue data. However, quantitative analysis of in-situ monitoring data enabled prediction of variability in defect content and mechanical performance.
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| 9. |
- Liu, Ye, et al.
(författare)
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First-principles investigation on the thermodynamic and mechanical properties of Y4Zr3O12 and Y2Ti2O7 oxides in ferritic alloy under helium environment
- 2024
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Ingår i: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854. ; 29, s. 1872-1886
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the thermodynamic and mechanical properties of Y4Zr3O12 and Y2Ti2O7 oxides in ferritic alloys with and without Helium utilizing a systematic first-principles approach. Firstly, the atomic arrangement of Y and Zr atoms at cation 18f sites in δ-(Y–Zr–O) oxide is identified, while it is found that Y4Zr3O12 exhibits a more robust formation tendency than Y2Ti2O7. Furthermore, it is noted that both Y4Zr3O12 and Y2Ti2O7 oxides demonstrate a prior ability to trap Helium compared to the bcc-Fe matrix, which leads to a substantial enhancement on the stiffness of both oxides. The elastic moduli of both Y4Zr3O12 and Y2Ti2O7 oxide exhibit a gradual increase with the growing Helium concentration. As a result, the enhanced shear modulus of oxides and sustained shear modulus of the bcc-Fe matrix collectively contribute to the overall strength of ferritic alloys under Helium environments. The findings in this work propose valuable insights for guiding critical strategies in the design of high-performance oxide-dispersion-strengthened ferritic alloys, particularly for applications in Helium environments.
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| 10. |
- Loaiza, Tania, 1994-, et al.
(författare)
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Micromechanical response of dual-hardening martensitic bearing steel before and after rolling contact fatigue
- 2024
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Ingår i: Journal of Materials Research and Technology. - : Elsevier BV. - 2238-7854. ; 29, s. 4728-4734
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Tidskriftsartikel (refereegranskat)abstract
- Material decay in bearing steels under rolling contact fatigue (RCF) leads to fatigue initiation and failure. This study examines the local structure-property relationship in decayed material through in-situ compression testing of micropillars prepared from a dual-hardening martensitic bearing steel (Hybrid 60) before and after RCF testing. The results demonstrate a pronounced enhancement in local yield strength for decayed regions (2200–2340 MPa) as compared to non-decayed regions (1755–1780 MPa). The higher initial stress for dislocations glide in the decayed regions and their discontinuous yield behavior are attributed to the presence of ferrite microbands. Crystal plasticity simulations corroborated these findings, showingincreased critical resolved shear stress (CRSS) and reduced strain hardening in decayed samples.
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| 11. |
- Patt-Lafitte, Guillaume, et al.
(författare)
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Toughening and strengthening of visible light-cured hydroxyapatite thiol-ene resin composite intended as bone fixation using 2D textile
- 2024
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Ingår i: JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T. - : Elsevier BV. - 2238-7854. ; 29, s. 982-990
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Tidskriftsartikel (refereegranskat)abstract
- Metals plates and screws are the gold standard in metacarpal and phalangeal fracture fixation as they provide high stability to complex fractures. However, incidence rates of complications ranging from 42 to 92 % have been reported. Bone bioadhesive fixation based on light-cured thiol-ene technology and reinforced with hydroxyapatite (HA) is a promising solution for customizable devices with tailored mechanical properties and reduced soft tissue adhesion. The reinforcement of these thiol-ene composites with 2D textiles or meshes has been proposed; however, their role in the mechanical performance has not been explored. In this study, structural and mechanical behavior properties of a light-cured resin composite with thiol-ene precursors and HA in the presence and absence of one and three-layer of poly(ethylene terephthalate) (PET) meshes were assessed. The lack of effect of the meshes on the light-cure efficiency and the structural homogeneity of the cured composite is shown using Raman spectroscopy, water uptake measurements, and micro-computed tomography. The insertion of meshes increased the strength and energy to fracture of resin-based composite. The woven geometry of the PET meshes enables frictional sliding behavior, and reduced crack propagation ensuring integrity after matrix failure. This effect increases with the number of meshes and was significantly higher in bending than in tensile stress conditions. Related to hand and wrist fractures, the design of composite fixation devices, based on HA and meshes fillers can significantly increase the strength and toughening of those medical devices with a potential impact on post-operation by reducing mechanical mismatch of stress shielding and prevent complications due to material disintegration, resulting from the compliant and personalized bone bioadhesive fixation application.
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| 12. |
- Schwerz, Claudia, et al.
(författare)
-
Reduction of oxygen content in laser powder bed fusion process atmosphere - Effects on stochastic defect formation and mechanical properties
- 2024
-
Ingår i: JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T. - : ELSEVIER. - 2238-7854. ; 30, s. 4667-4681
-
Tidskriftsartikel (refereegranskat)abstract
- Stochastic defects in materials manufactured via laser powder bed fusion (LPBF) can severely compromise mechanical performance and are challenging to predict and detect, thus motivating the development of defect mitigation strategies. Particle oxidation is a factor well-known to generate defects by disturbing melt pool dynamics. If the particles are spatters, additional disturbances increase the likelihood of defect formation. In this study, restricting oxygen content in the process atmosphere to 50 ppm is investigated to minimize stochastic spatter-induced defects and improve the mechanical properties of Hastelloy X. Specimens were manufactured under this condition at two nominal layer thicknesses, analyzed for internal defects, and mechanically tested. Contrary to expectations, reducing the oxygen content did not prevent spatter-induced defect formation; rather, it could exacerbate the formation of more numerous and larger defects. Nevertheless, this tighter control of the process atmosphere led to significant microstructural refinement, which, when combined with sparse defects, resulted in improved fatigue performance. Despite the inherent ductility of Hastelloy X, the presence of abundant defects significantly larger than the microstructural characteristic size proved detrimental to fatigue performance. Notably, the occurrence of defects exhibited considerable variation across the build area, contributing to scatter in fatigue data. However, quantitative analysis of in-situ monitoring data enabled prediction of variability in defect content and mechanical performance.
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| 13. |
- Svahn, F., et al.
(författare)
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Microstructure and mechanical properties of a modified 316 austenitic stainless steel alloy manufactured by laser powder bed fusion
- 2024
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Ingår i: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854. ; 28, s. 1452-1462
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Tidskriftsartikel (refereegranskat)abstract
- A 316 austenitic stainless-steel alloy, with modified alloy composition, manufactured by laser powder bed fusion (L-PBF) has been investigated. The modification of the alloy composition included addition of niobium (Nb), tungsten (W) and copper (Cu), together with a reduction in the amount of molybdenum (Mo) and an increased amount of carbon (C). To find suitable process parameters, a parameter study by varying laser power, hatch distance and scan speed was performed, centered on typical parameters used for normal 316 L. As-built material from a selected parameter configuration was then subjected to different stress relief annealing heat treatments and ageing heat treatments. The effectiveness of the stress annealing was ranked using a deformation-based method. Microstructural characterization, hardness and room temperature tensile testing were done to evaluate the effect of stress relief and aging heat treatments.It was found that a higher volumetric energy was needed to build dense material, about ∼50 % higher compared to the volumetric energy input for normal 316 L. A subsequent aging heat treatment at 725 °C for 3 h increased the strength and hardness of the material. A reinforcement of the cellular microstructure by precipitation of carbides in between the cells is believed to be the main reason for this. To completely alleviate the residual stresses it was necessary to carry out a stress relief annealing process at 950 °C, which resulted in a removal of the cellular structure and a lower strength material.
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| 14. |
- Wang, Yunlei, et al.
(författare)
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Advance understanding of the synthesis process, special performance, and multidiscipline applications of SiC nanowires and the constructed composites
- 2024
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Ingår i: Journal of Materials Research and Technology. - : Elsevier BV. - 2238-7854. ; 29, s. 1131-1154
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Tidskriftsartikel (refereegranskat)abstract
- As research and development of nanocomposites receive more attention in today's fast-paced world. SiC nanowires (SiC NWs) and their composites exhibit numerous unique and exceptional properties. As a result, they are widely used in various fields such as the chemical industry, optoelectronic devices, electronic products, aerospace, and military applications. In this paper, we present a comprehensive summary of the synthesis technology, distinctive properties, and potential applications of SiC NWs and the composite constructed from them. The introduction begins with an overview of the basic concept and characteristics of SiC. It then provides a detailed list of common synthesis methods, including precursor infiltration pyrolysis, chemical vapor deposition, solvothermal synthesis, carbothermal reduction, template method, other methods of molten salt, controllable chemical etching, and self-assembly synthesis. The advantages and shortcomings of these methods are also discussed in the context of specific applications. Then, the special performance and multidisciplinary applications are displayed after summarizing the previous studies. Eventually, this review concludes with an outlook on future research regarding SiC NWs and their composite materials, highlighting major prospects, challenges to be addressed, and possible solutions in a wide range of areas. A systematic overview of the topic of interest actually helps to reveal patterns in research cognition, plays a potential role in fostering awareness of scientific innovation and cross-thinking, and also serves as a guide for scientific research and interest development.
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