Xianmeng Wang, Yongchun Guo, Mengyao Li, Yanqiang Bu
In this research, the activity of CaO in a CaO-SiO2-MgO-Al2O3-B2O3 blast furnace slag system at T = 1773 K was measured using the reference slag method with Sn as the metal solvent and CaF2-CaO as the reference slag. Based on the obtained experimental results, the iso-activity diagram of CaO in the CaO-SiO2-MgO-20%Al2O3-2.2%B2O3 slag system at 1773 K was drawn. The effects of R(w(CaO)/w(SiO2)) and w(MgO)/w(Al2O3) on the activities and activity coefficients of CaO were also discussed. The results show that when w(Al2O3) = 20 %, w(MgO)/w(Al2O3) = 0.50 and w(B2O3) = 2.2 %, the activities and activity coefficients of CaO in the blast furnace slag increase with an increase in R. When w(Al2O3) = 20 %, R = 1.30 and w(B2O3) = 2.2 %, the activities and activity coefficients of CaO in the blast furnace slag increase with an increase in w(MgO)/w(Al2O3).
本研究以 Sn 为金属溶剂，CaF2-CaO 为参比渣，采用参比渣法测定了 T = 1773 K 时 CaO-SiO2-MgO-Al2O3-B2O3 高炉炉渣体系中 CaO 的活性。根据获得的实验结果，绘制了 1773 K 时 CaO-SiO2-MgO-20%Al2O3-2.2%B2O3 熔渣体系中 CaO 的等活度图。还讨论了 R（w(CaO)/w(SiO2)）和 w(MgO)/w(Al2O3)对 CaO 活性和活性系数的影响。结果表明，当 w(Al2O3) = 20 %、w(MgO)/w(Al2O3) = 0.50 和 w(B2O3) = 2.2 % 时，高炉渣中 CaO 的活度和活度系数随 R 的增大而增大。当 w(Al2O3) = 20 %、R = 1.30 和 w(B2O3) = 2.2 % 时，高炉渣中 CaO 的活度和活度系数随 w(MgO)/w(Al2O3) 的增加而增加。
{"title":"THERMODYNAMIC PROPERTIES OF CaO-SiO2-MgO-Al2O3-B2O3 SLAG SYSTEMS AT 1773 K","authors":"Xianmeng Wang, Yongchun Guo, Mengyao Li, Yanqiang Bu","doi":"10.17222/mit.2023.897","DOIUrl":"https://doi.org/10.17222/mit.2023.897","url":null,"abstract":"In this research, the activity of CaO in a CaO-SiO2-MgO-Al2O3-B2O3 blast furnace slag system at T = 1773 K was measured using the reference slag method with Sn as the metal solvent and CaF2-CaO as the reference slag. Based on the obtained experimental results, the iso-activity diagram of CaO in the CaO-SiO2-MgO-20%Al2O3-2.2%B2O3 slag system at 1773 K was drawn. The effects of R(w(CaO)/w(SiO2)) and w(MgO)/w(Al2O3) on the activities and activity coefficients of CaO were also discussed. The results show that when w(Al2O3) = 20 %, w(MgO)/w(Al2O3) = 0.50 and w(B2O3) = 2.2 %, the activities and activity coefficients of CaO in the blast furnace slag increase with an increase in R. When w(Al2O3) = 20 %, R = 1.30 and w(B2O3) = 2.2 %, the activities and activity coefficients of CaO in the blast furnace slag increase with an increase in w(MgO)/w(Al2O3).","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"12 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138980311","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 tool life of a hob milling tool and its cutting parameters have the greatest impact on gear cutting costs. The aim in this research was to model the tool life function of a hob milling tool, taking into account its impact on production costs. Experimental research of the tool life of a model single-tooth hob milling tool was carried out. On the basis of the obtained measurement results and by applying genetic programming, the tool life function of the hob milling tool was modelled. The paper presents a new model of the tool life function of the model single-tooth hob milling tool depending on the input cutting parameters, which include the cutting speed, axial feed and tangential feed.
{"title":"MODELING OF THE TOOL LIFE FUNCTION OF A HOB MILLING TOOL USING GENETIC PROGRAMMING","authors":"S. Sovilj-Nikić, I. Sovilj-Nikić, B. Sovilj","doi":"10.17222/mit.2023.954","DOIUrl":"https://doi.org/10.17222/mit.2023.954","url":null,"abstract":"The tool life of a hob milling tool and its cutting parameters have the greatest impact on gear cutting costs. The aim in this research was to model the tool life function of a hob milling tool, taking into account its impact on production costs. Experimental research of the tool life of a model single-tooth hob milling tool was carried out. On the basis of the obtained measurement results and by applying genetic programming, the tool life function of the hob milling tool was modelled. The paper presents a new model of the tool life function of the model single-tooth hob milling tool depending on the input cutting parameters, which include the cutting speed, axial feed and tangential feed.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"205 5","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138981303","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}
Electrochemical micromachining (ECMM) is a well know for manufacturing hard-to-cut materials, e.g., nickel-based alloys, titanium alloys and metal-matrix composites. For this reason it finds application in aerospace, automobile and biomedical industries. In this research Hastelloy C-276 is used as a workpiece and stainless-steel electrode coated with polytetrafluoroethylene (PTFE) to avoid stray current. The effect of process parameters such as voltage, duty cycle and electrolyte concentration on the machining speed and the surface-corrosion factor were studied. The range of 9–11 V has an impact on the machining speed. The electrolyte concentration range of 25–35 g/L shows a linear increase in the machining speed and the surface-corrosion factor is found to be highest at 1.1449 for an electrolyte concentration of 15g/L. The surface roughness depth profile depicts the values of Rz, Rt, Ra are 16.3 µm, 99.1 µm and 1.90 µm, and 15.4 µm, 50.6 µm and 1.49 µm, respectively.
{"title":"EFFECT OF ELECTROCHEMICAL PROCESS PARAMETERS ON THE HASTELLOY C-276 ALLOY FOR MACHINING SPEED AND SURFACE-CORROSION FACTOR","authors":"P. Venugopal, T. G. Arul, V. Selvam, K. Saranya","doi":"10.17222/mit.2023.981","DOIUrl":"https://doi.org/10.17222/mit.2023.981","url":null,"abstract":"Electrochemical micromachining (ECMM) is a well know for manufacturing hard-to-cut materials, e.g., nickel-based alloys, titanium alloys and metal-matrix composites. For this reason it finds application in aerospace, automobile and biomedical industries. In this research Hastelloy C-276 is used as a workpiece and stainless-steel electrode coated with polytetrafluoroethylene (PTFE) to avoid stray current. The effect of process parameters such as voltage, duty cycle and electrolyte concentration on the machining speed and the surface-corrosion factor were studied. The range of 9–11 V has an impact on the machining speed. The electrolyte concentration range of 25–35 g/L shows a linear increase in the machining speed and the surface-corrosion factor is found to be highest at 1.1449 for an electrolyte concentration of 15g/L. The surface roughness depth profile depicts the values of Rz, Rt, Ra are 16.3 µm, 99.1 µm and 1.90 µm, and 15.4 µm, 50.6 µm and 1.49 µm, respectively.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"25 2","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138978859","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}
A new thermosetting polyurethane modified asphalt (TPUA) pavement material was developed to solve the unbalanced performance of traditional bridge deck pavement materials. Compared with the conventional bridge deck pavement materials, this work comprehensively evaluates the pavement performance of the TPUA binder and its mixture. The results indicate that the TPUA binder gradually shows elastic material properties at high temperatures and has excellent deformation resistance. The low-temperature flexibility of the TPUA binder is much better than that of SBS asphalt and epoxy asphalt (EA) binders. The TPUA binder is a viscoelastic material at low temperatures, and its creep meets the Burgers constitutive model. Moreover, the TPUA binder also has excellent mechanical properties and flexibility. In addition, the TPUA mixture has excellent mechanical properties, high-temperature deformation resistance and moisture stability. Its crack resistance at room temperature and low temperature is much better than those of SBS asphalt and EA mixture. This work will help us continue the development and performance research of TPUA pavement materials.
为了解决传统桥面铺装材料性能不均衡的问题，一种新型热固性聚氨酯改性沥青（TPUA）铺装材料应运而生。与传统桥面铺装材料相比，本研究全面评估了 TPUA 粘结料及其混合料的铺装性能。结果表明，TPUA 粘结剂在高温下逐渐显示出弹性材料特性，并具有优异的抗变形能力。TPUA 粘结剂的低温柔韧性远远优于 SBS 沥青和环氧沥青（EA）粘结剂。TPUA 粘合剂在低温下是一种粘弹性材料，其蠕变符合伯格斯构成模型。此外，TPUA 粘结剂还具有优异的机械性能和柔韧性。此外，TPUA 混合物还具有优异的机械性能、耐高温变形性和湿稳定性。其在室温和低温下的抗裂性也远远优于 SBS 沥青和 EA 混合料。这项工作将有助于我们继续开展 TPUA 路面材料的开发和性能研究。
{"title":"923 PERFORMANCE CHARACTERISTICS OF THERMOSETTING POLYURETHANE MODIFIED ASPHALT BINDER AND ITS MIXTURES","authors":"Qian Zhou, Fan Yang, Liming Yang, Shiguang Tang","doi":"10.17222/mit.2023.923","DOIUrl":"https://doi.org/10.17222/mit.2023.923","url":null,"abstract":"A new thermosetting polyurethane modified asphalt (TPUA) pavement material was developed to solve the unbalanced performance of traditional bridge deck pavement materials. Compared with the conventional bridge deck pavement materials, this work comprehensively evaluates the pavement performance of the TPUA binder and its mixture. The results indicate that the TPUA binder gradually shows elastic material properties at high temperatures and has excellent deformation resistance. The low-temperature flexibility of the TPUA binder is much better than that of SBS asphalt and epoxy asphalt (EA) binders. The TPUA binder is a viscoelastic material at low temperatures, and its creep meets the Burgers constitutive model. Moreover, the TPUA binder also has excellent mechanical properties and flexibility. In addition, the TPUA mixture has excellent mechanical properties, high-temperature deformation resistance and moisture stability. Its crack resistance at room temperature and low temperature is much better than those of SBS asphalt and EA mixture. This work will help us continue the development and performance research of TPUA pavement materials.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"10 3","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138980805","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}
Matjaž Godec, Črtomir Donik, Aleksandra Kocijan, Irena Paulin
PROGRAM AND BOOK OF ABSTRACTS
程序和摘要书
{"title":"PROGRAM AND BOOK OF ABSTRACTS ICM&T 2023","authors":"Matjaž Godec, Črtomir Donik, Aleksandra Kocijan, Irena Paulin","doi":"10.17222/mit.1022.2023","DOIUrl":"https://doi.org/10.17222/mit.1022.2023","url":null,"abstract":"PROGRAM AND BOOK OF ABSTRACTS","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134945186","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}
An AA2024-T6 aluminium alloy was welded with a rotary-friction-welding technique using different forging pressures under constant friction pressure. It was found out that the increasing forging pressure has an adverse effect on the tensile strength of the welded joint. The maximum tensile strength was 366.22 MPa for a forging pressure of 80 MPa. However, the failure energies and elongations were decreased as the forging pressure increased. The minimum elongation was 15.45 %, while the minimum failure energy was 4.35 J with a forging pressure of 120 MPa. This situation is attributed to the loss of ductility up to a degree in high forging pressures and temperatures induced in the HAZ. In microstructural examinations the existence of the S phase has dominant role in determining the local hardness. The S phase is affected by the welding heat in the heat-affected zone, the thermomechanically affected zone and the dynamically recrystallized zone. The hardness is increased up to the middle of the TMAZ. In this zone the heat input caused an aging effect and increased the dispersed S phase in the intergranular zones. The aging mainly governed by the heat input increased the hardness up to beginning of the recrystallization zone.
{"title":"EFFECT OF DIFFERENT APPLICATION PRESSURES ON ROTARY-FRICTION-WELDED AA2024-T6 JOINTS","authors":"Serkan Apay, Fatih Özen, Volkan Onar","doi":"10.17222/mit.2023.834","DOIUrl":"https://doi.org/10.17222/mit.2023.834","url":null,"abstract":"An AA2024-T6 aluminium alloy was welded with a rotary-friction-welding technique using different forging pressures under constant friction pressure. It was found out that the increasing forging pressure has an adverse effect on the tensile strength of the welded joint. The maximum tensile strength was 366.22 MPa for a forging pressure of 80 MPa. However, the failure energies and elongations were decreased as the forging pressure increased. The minimum elongation was 15.45 %, while the minimum failure energy was 4.35 J with a forging pressure of 120 MPa. This situation is attributed to the loss of ductility up to a degree in high forging pressures and temperatures induced in the HAZ. In microstructural examinations the existence of the S phase has dominant role in determining the local hardness. The S phase is affected by the welding heat in the heat-affected zone, the thermomechanically affected zone and the dynamically recrystallized zone. The hardness is increased up to the middle of the TMAZ. In this zone the heat input caused an aging effect and increased the dispersed S phase in the intergranular zones. The aging mainly governed by the heat input increased the hardness up to beginning of the recrystallization zone.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135743640","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}
In this paper, a molecular dynamics simulation was used to examine the physical, mechanical, and interfacial adhesion characteristics of graphene-modified asphalt. The results show that the physical properties, mechanical properties and interfacial adhesion work of modified graphene are higher than those of the base asphalt model, indicating that the addition of graphene can improve the mechanical properties and interfacial interaction of asphalt. Asphalt and aggregate mainly interact through physical adsorption, and the Van der Waals force plays an important role in the adhesion behavior of the asphalt-calcite interface. There is an optimal value for the content of graphene, such that the content of graphene added to the asphalt should not be too high. Considering the graphene price factor and modification effect, the graphene content studied is optimal at 1.79 w/%.
{"title":"STUDY OF THE PROPERTIES AND INTERFACIAL ENERGY OF GRAPHENE-MODIFIED ASPHALT BASED ON MOLECULAR DYNAMICS","authors":"Zhenlong Mo","doi":"10.17222/mit.2023.878","DOIUrl":"https://doi.org/10.17222/mit.2023.878","url":null,"abstract":"In this paper, a molecular dynamics simulation was used to examine the physical, mechanical, and interfacial adhesion characteristics of graphene-modified asphalt. The results show that the physical properties, mechanical properties and interfacial adhesion work of modified graphene are higher than those of the base asphalt model, indicating that the addition of graphene can improve the mechanical properties and interfacial interaction of asphalt. Asphalt and aggregate mainly interact through physical adsorption, and the Van der Waals force plays an important role in the adhesion behavior of the asphalt-calcite interface. There is an optimal value for the content of graphene, such that the content of graphene added to the asphalt should not be too high. Considering the graphene price factor and modification effect, the graphene content studied is optimal at 1.79 w/%.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135744175","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}
There is an increasing demand for higher machining quality and service life of the cutting tools used for the machining of high-strength alloys. Various studies revealed that textured cutting tools could improve the cutting performance by enhancing the tribological characteristics of the cutting regime. Advances in precision machining enabled the creation of micro/nano-textures on tool surfaces with excellent dimensional control. In this work, distinct micro designs, viz. horizontal line, vertical line and cross-hatch, are made, varying the pitch on the rake faces of coated carbide cutting inserts (CCMT060202LF KC5010). An in-house micro-turning machine was utilized to perform all the experiments in dry-cutting conditions. Micro-turning operations were performed using plain and textured inserts and varying the cutting parameters under dry conditions. The effectiveness of micro-scale textures at a contact interface was evaluated based on the cutting forces, tool flank wear and surface roughness. Compared to non-textured inserts, the machining using cross-hatch textured inserts with 100 µm pitch resulted in 50 % lower cutting forces, a 45 % improved surface finish and 37 % reduced tool flank wear. When machining with horizontal-line textured inserts with a 100 µm pitch, cutting forces are reduced by 46 %, the surface finish is enhanced by 34 % and the tool flank wear is lowered by 30 %. Similarly, when machining with vertical-line textured inserts with a 100 µm pitch, cutting forces are minimized by 38 %, the surface finish is improved by 20 % and the tool flank wear is lowered by 26 %. Additionally, a durability test was conducted for the inserts, and the results showed that the cross-hatch textured tool life improved by 80 %, the life of the horizontal-line textured tool increased by 50 % and the life of the vertical-line textured tool increased by 40 % compared to plain inserts. The heat dissipation and tool-chip friction during machining are thus significantly influenced by the texturing, namely by its design, dimensions and orientation.
{"title":"EFFECT OF TEXTURED CUTTING INSERTS IN MICRO-TURNING OF TI-6AL-4V ALLOYS","authors":"Samuel G.L., Rajesh Babu Tere","doi":"10.17222/mit.2023.828","DOIUrl":"https://doi.org/10.17222/mit.2023.828","url":null,"abstract":"There is an increasing demand for higher machining quality and service life of the cutting tools used for the machining of high-strength alloys. Various studies revealed that textured cutting tools could improve the cutting performance by enhancing the tribological characteristics of the cutting regime. Advances in precision machining enabled the creation of micro/nano-textures on tool surfaces with excellent dimensional control. In this work, distinct micro designs, viz. horizontal line, vertical line and cross-hatch, are made, varying the pitch on the rake faces of coated carbide cutting inserts (CCMT060202LF KC5010). An in-house micro-turning machine was utilized to perform all the experiments in dry-cutting conditions. Micro-turning operations were performed using plain and textured inserts and varying the cutting parameters under dry conditions. The effectiveness of micro-scale textures at a contact interface was evaluated based on the cutting forces, tool flank wear and surface roughness. Compared to non-textured inserts, the machining using cross-hatch textured inserts with 100 µm pitch resulted in 50 % lower cutting forces, a 45 % improved surface finish and 37 % reduced tool flank wear. When machining with horizontal-line textured inserts with a 100 µm pitch, cutting forces are reduced by 46 %, the surface finish is enhanced by 34 % and the tool flank wear is lowered by 30 %. Similarly, when machining with vertical-line textured inserts with a 100 µm pitch, cutting forces are minimized by 38 %, the surface finish is improved by 20 % and the tool flank wear is lowered by 26 %. Additionally, a durability test was conducted for the inserts, and the results showed that the cross-hatch textured tool life improved by 80 %, the life of the horizontal-line textured tool increased by 50 % and the life of the vertical-line textured tool increased by 40 % compared to plain inserts. The heat dissipation and tool-chip friction during machining are thus significantly influenced by the texturing, namely by its design, dimensions and orientation.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135744875","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}
Fabio Miranda, Marcelo Otavio Dos Santos, Daniel Rodrigues, Rodrigo Santiago Coelho, Gilmar Ferreira Batalha
The production of carbide parts (cermet) by additive manufacturing, such as laser powder bed fusion (L-PBF), has been a great challenge due to the complex optimization of process parameters to improve density, porosity, microcracks or abnormal growth of grains and obtain a microstructure as homogeneous as possible. This work aims to compare the evolution of the microstructure when using the conventional route of powder metallurgy, i.e., liquid phase sintering (LPS) with the L-PBF direct additive manufacturing process, considering the NbC-based carbide material. Sample compositions were prepared in w/%, samples were compacted under 50–125 MPa, without polymeric binders, and they were sintered under a vacuum at temperatures of 1330 °C and 1370 °C. For the L-PBF process, a vibrating device made it possible to improve the fluidity of the mixtures of three alloys, NbC–30Co, NbC–30Ni and NbC–30(Co, Ni). The mixtures exhibited low sphericity, low fluidity and compressibility, which were improved with a roller compactor. Thin powder mixture deposition layers were evenly applied and well distributed across the powder bed to avoid defects and cracks during sintering. The L-PBF process parameters varied including a power of 50–125 W and a laser scanning speed of 25–125 mm·s–1. Different microstructures, identified with a light microscope (LM) and a scanning electron microscope (SEM), and properties obtained with the two processes, direct (L–PBF) and indirect sintering (LPS), were compared.
{"title":"NbC-BASED CERMET PRODUCTION COMPARISON: L-PBF ADDITIVE MANUFACTURING VERSUS CONVENTIONAL LPS POWDER METALLURGY","authors":"Fabio Miranda, Marcelo Otavio Dos Santos, Daniel Rodrigues, Rodrigo Santiago Coelho, Gilmar Ferreira Batalha","doi":"10.17222/mit.2023.972","DOIUrl":"https://doi.org/10.17222/mit.2023.972","url":null,"abstract":"The production of carbide parts (cermet) by additive manufacturing, such as laser powder bed fusion (L-PBF), has been a great challenge due to the complex optimization of process parameters to improve density, porosity, microcracks or abnormal growth of grains and obtain a microstructure as homogeneous as possible. This work aims to compare the evolution of the microstructure when using the conventional route of powder metallurgy, i.e., liquid phase sintering (LPS) with the L-PBF direct additive manufacturing process, considering the NbC-based carbide material. Sample compositions were prepared in w/%, samples were compacted under 50–125 MPa, without polymeric binders, and they were sintered under a vacuum at temperatures of 1330 °C and 1370 °C. For the L-PBF process, a vibrating device made it possible to improve the fluidity of the mixtures of three alloys, NbC–30Co, NbC–30Ni and NbC–30(Co, Ni). The mixtures exhibited low sphericity, low fluidity and compressibility, which were improved with a roller compactor. Thin powder mixture deposition layers were evenly applied and well distributed across the powder bed to avoid defects and cracks during sintering. The L-PBF process parameters varied including a power of 50–125 W and a laser scanning speed of 25–125 mm·s–1. Different microstructures, identified with a light microscope (LM) and a scanning electron microscope (SEM), and properties obtained with the two processes, direct (L–PBF) and indirect sintering (LPS), were compared.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135739651","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}
In this research, the influences of the tempering temperature on the microstructure and ultimate tensile strength of 28Cr3SiNiMoWV steel were studied. The microstructure and ultimate tensile strength were investigated after tempering 28Cr3SiNiMoWV steel at different temperatures, ranging from 280 °C to 440 °C for 2 h. The results show that after tempering it at different temperatures, the microstructure of 28Cr3SiNiMoWV steel was tempered martensite. During the tempering process, the alloy carbides precipitated in the martensite matrix. Precipitation of alloy carbides in the microstructures of different specimens is the cause for an increase in the ultimate tensile strength. With the increasing tempering temperature, the ultimate tensile strength initially increases from 1390 MPa to 1601 MPa, and then decreases to 1466 MPa, with its maximum value at 280 °C.
{"title":"INFLUENCE OF TEMPERING TEMPERATURE ON THE MICROSTRUCTURE AND ULTIMATE TENSILE STRENGTH OF 28Cr3SiNiMoWV STEEL","authors":"Ngoc Minh Nguyen, Hanh Ngan Vu","doi":"10.17222/mit.2023.787","DOIUrl":"https://doi.org/10.17222/mit.2023.787","url":null,"abstract":"In this research, the influences of the tempering temperature on the microstructure and ultimate tensile strength of 28Cr3SiNiMoWV steel were studied. The microstructure and ultimate tensile strength were investigated after tempering 28Cr3SiNiMoWV steel at different temperatures, ranging from 280 °C to 440 °C for 2 h. The results show that after tempering it at different temperatures, the microstructure of 28Cr3SiNiMoWV steel was tempered martensite. During the tempering process, the alloy carbides precipitated in the martensite matrix. Precipitation of alloy carbides in the microstructures of different specimens is the cause for an increase in the ultimate tensile strength. With the increasing tempering temperature, the ultimate tensile strength initially increases from 1390 MPa to 1601 MPa, and then decreases to 1466 MPa, with its maximum value at 280 °C.","PeriodicalId":18258,"journal":{"name":"Materiali in tehnologije","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135739789","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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