This work aims to study the microstructural development of lead-containing aluminum alloy in the process of intense plastic deformation. The evolution of the AA2030 alloy obtained by the ECAP and long-term natural aging (within 45 months) has been analyzed using electron microscopes. The average grain size of the ECAP treated samples is 420 and 380 nm along the routes Bc and C, respectively. Long-term natural aging contributes to transforming grain boundaries without changing their size. The results have shown that the structure, phase distribution, and stoichiometric composition of the inclusions differ significantly during annealing, equal-channel angular pressing, and long-term natural aging. The strain route affects the dissolution kinetics and evolution of inclusions. A mechanism for refining the grains is proposed that is associated with high dislocation density, dislocation cells, grain and subgrain boundaries, as well as the evolution of inclusions in the ECAP AA2030 alloys. K e y w o r d s: aluminum alloys, AA2030, SPD, ECAP, grains and interfaces, electron microscopy
{"title":"Evolution of the AA2030 alloy microstructure in the ECAP process","authors":"Violetta A. Andreyachshenko","doi":"10.31577/km.2022.2.79","DOIUrl":"https://doi.org/10.31577/km.2022.2.79","url":null,"abstract":"This work aims to study the microstructural development of lead-containing aluminum alloy in the process of intense plastic deformation. The evolution of the AA2030 alloy obtained by the ECAP and long-term natural aging (within 45 months) has been analyzed using electron microscopes. The average grain size of the ECAP treated samples is 420 and 380 nm along the routes Bc and C, respectively. Long-term natural aging contributes to transforming grain boundaries without changing their size. The results have shown that the structure, phase distribution, and stoichiometric composition of the inclusions differ significantly during annealing, equal-channel angular pressing, and long-term natural aging. The strain route affects the dissolution kinetics and evolution of inclusions. A mechanism for refining the grains is proposed that is associated with high dislocation density, dislocation cells, grain and subgrain boundaries, as well as the evolution of inclusions in the ECAP AA2030 alloys. K e y w o r d s: aluminum alloys, AA2030, SPD, ECAP, grains and interfaces, electron microscopy","PeriodicalId":49937,"journal":{"name":"Kovove Materialy-Metallic Materials","volume":"7 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87408109","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}
J. Koráb, Stanislav Kúdela, Jr., P. Štefánik, F. Simančík, N. Beronská, P. Tobolka
The paper presents the designing, technology, and characterising mechanical and damping properties of two types of structural components that might be useful in space applications. The components (struts) were produced by the gas pressure infiltration of molten Mg into a preform of continuous carbon fibres. For comparison, also a non-reinforced component from pure Mg was prepared. Vibroacoustic tests showed that the samples reinforced with carbon fibres had better damping – approximately two times higher loss factor (η = 0.0018 and η = 0.0021) than the cast Mg component (η = 0.0008). The bending tests confirmed the results obtained by vibroacoustic testing and revealed that the stiffness of the reinforced structural component was approximately six times higher than that of the unreinforced Mg material. K e y w o r d s: metal matrix composites, magnesium matrix, carbon fibre, gas pressure infiltration, space application
{"title":"Design and testing of a simple structural component for space applications","authors":"J. Koráb, Stanislav Kúdela, Jr., P. Štefánik, F. Simančík, N. Beronská, P. Tobolka","doi":"10.31577/km.2022.2.131","DOIUrl":"https://doi.org/10.31577/km.2022.2.131","url":null,"abstract":"The paper presents the designing, technology, and characterising mechanical and damping properties of two types of structural components that might be useful in space applications. The components (struts) were produced by the gas pressure infiltration of molten Mg into a preform of continuous carbon fibres. For comparison, also a non-reinforced component from pure Mg was prepared. Vibroacoustic tests showed that the samples reinforced with carbon fibres had better damping – approximately two times higher loss factor (η = 0.0018 and η = 0.0021) than the cast Mg component (η = 0.0008). The bending tests confirmed the results obtained by vibroacoustic testing and revealed that the stiffness of the reinforced structural component was approximately six times higher than that of the unreinforced Mg material. K e y w o r d s: metal matrix composites, magnesium matrix, carbon fibre, gas pressure infiltration, space application","PeriodicalId":49937,"journal":{"name":"Kovove Materialy-Metallic Materials","volume":"12 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74936468","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}
The applicability of the diffusion brazing technique for bonding Nicrofer 5520 superalloy was assessed. The experiments were carried out at 1120◦C for 5, 15, 20, 45, 90, 120, and 240 min holding times using 30 μm thick Ni-7%Cr4.5%Si-3.1%B interlayers. The microstructure, shear strength, and microhardness of the resultant joints were investigated. The results showed that the complete isothermal solidification (CIS) occurred after 20 min-holding time. The (Mo, Cr, Ni, Fe)-rich carbides and (Cr, Mo)-rich borides with various morphologies were observed in the diffusion-affected zone (DAZ). Before CIS, a Ni-rich boride and Ni-rich silicide along with Cr and Mo-rich borides were also detected in the centerline. After CIS, the volume fraction of precipitated phases in the DAZ region was reduced by increasing the holding time. Simultaneously, the chemical composition became more uniform; also, the shear strength of the specimens was improved, and for the 240 min-holding time, it reached about 93 % of that of the base metal. K e y w o r d s: Nicrofer 5520, diffusion brazing, bonding time, microstructure, mechanical properties
{"title":"Diffusion brazing of Nicrofer 5520 (IN-617) superalloy using an amorphous Ni-Cr-Si-B interlayer: Microstructural characterization and mechanical properties","authors":"Ali Nasajpour, Seyyed Ehsan Mirsalehi, A. Farzadi","doi":"10.31577/km.2022.2.89","DOIUrl":"https://doi.org/10.31577/km.2022.2.89","url":null,"abstract":"The applicability of the diffusion brazing technique for bonding Nicrofer 5520 superalloy was assessed. The experiments were carried out at 1120◦C for 5, 15, 20, 45, 90, 120, and 240 min holding times using 30 μm thick Ni-7%Cr4.5%Si-3.1%B interlayers. The microstructure, shear strength, and microhardness of the resultant joints were investigated. The results showed that the complete isothermal solidification (CIS) occurred after 20 min-holding time. The (Mo, Cr, Ni, Fe)-rich carbides and (Cr, Mo)-rich borides with various morphologies were observed in the diffusion-affected zone (DAZ). Before CIS, a Ni-rich boride and Ni-rich silicide along with Cr and Mo-rich borides were also detected in the centerline. After CIS, the volume fraction of precipitated phases in the DAZ region was reduced by increasing the holding time. Simultaneously, the chemical composition became more uniform; also, the shear strength of the specimens was improved, and for the 240 min-holding time, it reached about 93 % of that of the base metal. K e y w o r d s: Nicrofer 5520, diffusion brazing, bonding time, microstructure, mechanical properties","PeriodicalId":49937,"journal":{"name":"Kovove Materialy-Metallic Materials","volume":"29 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80394363","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}
V. Gobbi, S. Gobbi, Danieli Aparecida Pereira Reis, Jorge Luiz de Almeida Ferreira, J. A. Araújo, C. D. da Silva
New superalloys are constantly being developed to fulfill the increased demand for alloys with high creep resistance and low manufacturing costs. This study subjected two alloys to comparative creep tests and microstructural characterization. A novel low-cost iron-nickel superalloy with intermediate Ni and Fe content was designated in this work as Fe-Ni-Cr and the NIMONIC 80A with a high Ni. Creep experiments were carried out at temperatures ranging from 650 to 750 ◦ C and loads ranging from 500 to 600 MPa. Microstructural characterization and surface analysis were carried out using microscopy techniques such as optical, SEM with EDS, and TEM. For phase quantitative identification, Rietveld refinement was utilized. Compared to NIMONIC 80A, the new Fe-Ni-Cr superalloy showed higher creep resistance. The Fe-Ni-Cr alloy has higher percentages of carbon and iron and the addition of niobium, resulting in the formation of γ (cid:3) intermetallics and carbides rich in iron and niobium. These carbides and intermetallics operate as obstacles to dislocation glide and climb, lowering the creep rate. Compared to Fe-Ni-Cr, the reduced carbides in NIMONIC 80A promote relative slip between grains during deformation, facilitating creep rate acceleration and early failure.
{"title":"Creep behavior and microstructural characterization of iron-nickel and nickel-based superalloys","authors":"V. Gobbi, S. Gobbi, Danieli Aparecida Pereira Reis, Jorge Luiz de Almeida Ferreira, J. A. Araújo, C. D. da Silva","doi":"10.31577/km.2022.2.67","DOIUrl":"https://doi.org/10.31577/km.2022.2.67","url":null,"abstract":"New superalloys are constantly being developed to fulfill the increased demand for alloys with high creep resistance and low manufacturing costs. This study subjected two alloys to comparative creep tests and microstructural characterization. A novel low-cost iron-nickel superalloy with intermediate Ni and Fe content was designated in this work as Fe-Ni-Cr and the NIMONIC 80A with a high Ni. Creep experiments were carried out at temperatures ranging from 650 to 750 ◦ C and loads ranging from 500 to 600 MPa. Microstructural characterization and surface analysis were carried out using microscopy techniques such as optical, SEM with EDS, and TEM. For phase quantitative identification, Rietveld refinement was utilized. Compared to NIMONIC 80A, the new Fe-Ni-Cr superalloy showed higher creep resistance. The Fe-Ni-Cr alloy has higher percentages of carbon and iron and the addition of niobium, resulting in the formation of γ (cid:3) intermetallics and carbides rich in iron and niobium. These carbides and intermetallics operate as obstacles to dislocation glide and climb, lowering the creep rate. Compared to Fe-Ni-Cr, the reduced carbides in NIMONIC 80A promote relative slip between grains during deformation, facilitating creep rate acceleration and early failure.","PeriodicalId":49937,"journal":{"name":"Kovove Materialy-Metallic Materials","volume":"2014 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86768998","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}
The joining of magnesium alloys with conventional fusion welding methods often causes porosity and hot cracking defects. The use of friction stir welding, a solid-state welding technique for joining Mg alloys, solves these problems. In this study, AZ31B Mg sheets with 3 mm in thickness were joined by friction stir welding at a constant feed rate (50 mmmin−1) and different tool rotational speeds (900 and 1400 rpm), and different tool tilt angles (0◦ and 1.5◦) using tapered pin. Tensile strength and microhardness tests were carried out to examine the mechanical properties of the welded specimens. The microstructures of the welded zone were analyzed by obtaining optical microscopy and scanning electron microscopy images. According to the tensile test results, specimen welded at 50 mmmin−1 feed rate, 900 rpm tool rotational speed, and 1.5◦ tool tilt angle showed the highest welding strength value 176.03 MPa. K e y w o r d s: friction stir welding, magnesium alloys, welding parameters, microstructure, tensile strength
{"title":"Evaluation of welding parameters effects in friction stir welding of AZ31B Mg alloy","authors":"F. Tolun","doi":"10.31577/km.2022.2.109","DOIUrl":"https://doi.org/10.31577/km.2022.2.109","url":null,"abstract":"The joining of magnesium alloys with conventional fusion welding methods often causes porosity and hot cracking defects. The use of friction stir welding, a solid-state welding technique for joining Mg alloys, solves these problems. In this study, AZ31B Mg sheets with 3 mm in thickness were joined by friction stir welding at a constant feed rate (50 mmmin−1) and different tool rotational speeds (900 and 1400 rpm), and different tool tilt angles (0◦ and 1.5◦) using tapered pin. Tensile strength and microhardness tests were carried out to examine the mechanical properties of the welded specimens. The microstructures of the welded zone were analyzed by obtaining optical microscopy and scanning electron microscopy images. According to the tensile test results, specimen welded at 50 mmmin−1 feed rate, 900 rpm tool rotational speed, and 1.5◦ tool tilt angle showed the highest welding strength value 176.03 MPa. K e y w o r d s: friction stir welding, magnesium alloys, welding parameters, microstructure, tensile strength","PeriodicalId":49937,"journal":{"name":"Kovove Materialy-Metallic Materials","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88420582","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}
AA5083 aluminium alloy is an excellent casting material with inadequate strength and poor wear properties. To increase its deficient mechanical and wear properties, researchers have conducted a lot of research in the past decades. Based on the research, graphene can be considered a good reinforcement due to its outstanding mechanical properties. The present paper discusses the properties of AA5083 Metal Matrix Composites (MMCs) reinforced with graphene particles. Aluminium MMCs were fabricated using the stir casting method by varying graphene reinforcement (5 and 10 wt.%) with AA5083 (specimens B and C). The Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDAX) analysis results confirmed the presence of graphene in the AA5083 matrix. The test results show that the tensile strength, flexural strength, impact strength, and hardness were enhanced with the addition of graphene particles in the AA5083 matrix. The tribological behaviour of the MMCs was compared with the AA5083 matrix using a pin-on-disc wear test. The increase in wt.% of graphene reinforcement enhanced the wear resistance of the proposed MMCs. The large wear debris and crater were not noticed in the worn surfaces of the MMCs specimens.
{"title":"Study of mechanical and wear behaviour of AA5083 graphene reinforced composites","authors":"S. S. Kumar, S. Kumar, U. Magarajan, S. Divya","doi":"10.31577/km.2022.2.121","DOIUrl":"https://doi.org/10.31577/km.2022.2.121","url":null,"abstract":"AA5083 aluminium alloy is an excellent casting material with inadequate strength and poor wear properties. To increase its deficient mechanical and wear properties, researchers have conducted a lot of research in the past decades. Based on the research, graphene can be considered a good reinforcement due to its outstanding mechanical properties. The present paper discusses the properties of AA5083 Metal Matrix Composites (MMCs) reinforced with graphene particles. Aluminium MMCs were fabricated using the stir casting method by varying graphene reinforcement (5 and 10 wt.%) with AA5083 (specimens B and C). The Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDAX) analysis results confirmed the presence of graphene in the AA5083 matrix. The test results show that the tensile strength, flexural strength, impact strength, and hardness were enhanced with the addition of graphene particles in the AA5083 matrix. The tribological behaviour of the MMCs was compared with the AA5083 matrix using a pin-on-disc wear test. The increase in wt.% of graphene reinforcement enhanced the wear resistance of the proposed MMCs. The large wear debris and crater were not noticed in the worn surfaces of the MMCs specimens.","PeriodicalId":49937,"journal":{"name":"Kovove Materialy-Metallic Materials","volume":"30 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81801172","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":"A novel method based on probability theory for simultaneous optimization of multi-object orthogonal test design in material engineering","authors":"M. Zheng, Yi Wang, H. Teng","doi":"10.31577/km.2022.1.45","DOIUrl":"https://doi.org/10.31577/km.2022.1.45","url":null,"abstract":"","PeriodicalId":49937,"journal":{"name":"Kovove Materialy-Metallic Materials","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75864456","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}
O. Velgosova, Š. Nagy, M. Besterci,, V. Puchý, Z. Hájovská
{"title":"Fracture mechanism of mechanically alloyed Al composite","authors":"O. Velgosova, Š. Nagy, M. Besterci,, V. Puchý, Z. Hájovská","doi":"10.31577/km.2022.1.13","DOIUrl":"https://doi.org/10.31577/km.2022.1.13","url":null,"abstract":"","PeriodicalId":49937,"journal":{"name":"Kovove Materialy-Metallic Materials","volume":"17 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85256256","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 directionality of AZ31 magnesium alloy sheets produced by continuous variable cross-section direct extrusion on corrosion behavior","authors":"Cheng Guo Ma, W. Kang","doi":"10.31577/km.2022.1.1","DOIUrl":"https://doi.org/10.31577/km.2022.1.1","url":null,"abstract":"","PeriodicalId":49937,"journal":{"name":"Kovove Materialy-Metallic Materials","volume":"100 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74537493","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 thickness and build direction on the mechanical behavior and microstructure of AISI 316L stainless steel produced by Laser Beam Powder Bed Fusion","authors":"E. Yasa, M. Karasoglu","doi":"10.31577/km.2022.1.55","DOIUrl":"https://doi.org/10.31577/km.2022.1.55","url":null,"abstract":"","PeriodicalId":49937,"journal":{"name":"Kovove Materialy-Metallic Materials","volume":"17 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2022-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88459088","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}
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