Pub Date : 2024-11-23DOI: 10.1007/s12540-024-01856-w
Joon Beom Park, Moo Eob Choi, Hyeonwoo Park, Jiwoo Park, Joonho Lee
The dissolution rate of SiC in molten Fe–C alloys was investigated at 1673 ~ 1773 K, while the initial carbon concentration varied from approximately 2–3 wt%. The dissolution of SiC in molten Fe–C alloys occurred to reach the carbon-saturation composition. By assuming a first-order reaction, the dissolution rate constant was estimated to decrease from 8.17 × 10−3 to 2.90 × 10−3 cm/s, as the initial carbon content increased from 2 to 3 wt% at 1673 K. When the temperature increased from 1673 to 1773 K with the sample of the initial carbon content of about 2 wt%, the rate constant increased from 8.17 × 10−3 to 18.41 × 10−3 cm/s. The apparent activation energy was estimated at 199.5 kJ/mol. Based on the experimental results, an empirical equation was suggested for the estimation of the SiC dissolution rate constant: (ln kleft( {cm/s} right) = 12.74 - 1.37 times left[ {wt% C} right]_{t = 0} - 2.40 times 10^{4} /Tleft( K right)), which can be applied to the numerical simulation of the Si-pickup in the FINEX and the Hydrogen-enriched Blast Furnace operations.
Graphical Abstract
在1673 ～ 1773 K温度下，研究了SiC在Fe-C合金熔液中的溶解速率，而初始碳浓度约为2 ～ 3 wt%. The dissolution of SiC in molten Fe–C alloys occurred to reach the carbon-saturation composition. By assuming a first-order reaction, the dissolution rate constant was estimated to decrease from 8.17 × 10−3 to 2.90 × 10−3 cm/s, as the initial carbon content increased from 2 to 3 wt% at 1673 K. When the temperature increased from 1673 to 1773 K with the sample of the initial carbon content of about 2 wt%, the rate constant increased from 8.17 × 10−3 to 18.41 × 10−3 cm/s. The apparent activation energy was estimated at 199.5 kJ/mol. Based on the experimental results, an empirical equation was suggested for the estimation of the SiC dissolution rate constant: (ln kleft( {cm/s} right) = 12.74 - 1.37 times left[ {wt% C} right]_{t = 0} - 2.40 times 10^{4} /Tleft( K right)), which can be applied to the numerical simulation of the Si-pickup in the FINEX and the Hydrogen-enriched Blast Furnace operations.Graphical Abstract
{"title":"Kinetics of Silicon Carbide Dissolution in Molten Fe–C Alloys","authors":"Joon Beom Park, Moo Eob Choi, Hyeonwoo Park, Jiwoo Park, Joonho Lee","doi":"10.1007/s12540-024-01856-w","DOIUrl":"10.1007/s12540-024-01856-w","url":null,"abstract":"<div><p>The dissolution rate of SiC in molten Fe–C alloys was investigated at 1673 ~ 1773 K, while the initial carbon concentration varied from approximately 2–3 wt%. The dissolution of SiC in molten Fe–C alloys occurred to reach the carbon-saturation composition. By assuming a first-order reaction, the dissolution rate constant was estimated to decrease from 8.17 × 10<sup>−3</sup> to 2.90 × 10<sup>−3</sup> cm/s, as the initial carbon content increased from 2 to 3 wt% at 1673 K. When the temperature increased from 1673 to 1773 K with the sample of the initial carbon content of about 2 wt%, the rate constant increased from 8.17 × 10<sup>−3</sup> to 18.41 × 10<sup>−3</sup> cm/s. The apparent activation energy was estimated at 199.5 kJ/mol. Based on the experimental results, an empirical equation was suggested for the estimation of the SiC dissolution rate constant: <span>(ln kleft( {cm/s} right) = 12.74 - 1.37 times left[ {wt% C} right]_{t = 0} - 2.40 times 10^{4} /Tleft( K right))</span>, which can be applied to the numerical simulation of the Si-pickup in the FINEX and the Hydrogen-enriched Blast Furnace operations.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":703,"journal":{"name":"Metals and Materials International","volume":"30 12","pages":"3537 - 3543"},"PeriodicalIF":3.3,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-02DOI: 10.1007/s12540-024-01798-3
Cemal İrfan Çalışkan, Gökhan Özer, Hamaid Mahmood Khan
In our previous research within the scope of process parameters change, the innovative 30 µm synchronous scanning strategy (SSS) in the Laser Powder Bed Fusion production system and the effect of this scanning strategy on industrial gears were discussed in the microstructure examination of industrial gears produced with this scanning strategy. It was observed that the Additive Manufacturing (AM) traditional melt pool form changed, and the strength increased by approx. 23%. In this article, carried out in the second stage, a new microstructure in the form of bubbles obtained with this new synchronous scanning strategy, discussed in depth with laboratory research, is defined as “Bubble Microstructure.” This new microstructure definition, which constitutes the innovative side of the study, is in addition to the 30 µm SSS research that was discussed in the first phase of the study; 40 µm SSS production and research carried out at this stage are detailed within the scope of tensile tests in ASTM-E8 standard, detailed microstructure examinations in OM (Optic Microscope) and SEM (Scanning Electron Microscope), EDX, XRD analyzes and the mechanical strength effect of this microstructure on the Triple Periotic Minimal Surfaces geometry. This new SSS approach is considered promising in industrial areas where innovative geometries can be produced with AM, weight-reduced designs using topology optimization, and DfAM (Design for Additive Manufacturing) are used.
Graphical Abstract
{"title":"A Novel Form “Bubble Microstructure” in LPBF and Investigation of Its Mechanical Strength on TPMS-Gyroid","authors":"Cemal İrfan Çalışkan, Gökhan Özer, Hamaid Mahmood Khan","doi":"10.1007/s12540-024-01798-3","DOIUrl":"10.1007/s12540-024-01798-3","url":null,"abstract":"<div><p>In our previous research within the scope of process parameters change, the innovative 30 µm synchronous scanning strategy (SSS) in the Laser Powder Bed Fusion production system and the effect of this scanning strategy on industrial gears were discussed in the microstructure examination of industrial gears produced with this scanning strategy. It was observed that the Additive Manufacturing (AM) traditional melt pool form changed, and the strength increased by approx. 23%. In this article, carried out in the second stage, a new microstructure in the form of bubbles obtained with this new synchronous scanning strategy, discussed in depth with laboratory research, is defined as “Bubble Microstructure.” This new microstructure definition, which constitutes the innovative side of the study, is in addition to the 30 µm SSS research that was discussed in the first phase of the study; 40 µm SSS production and research carried out at this stage are detailed within the scope of tensile tests in ASTM-E8 standard, detailed microstructure examinations in OM (Optic Microscope) and SEM (Scanning Electron Microscope), EDX, XRD analyzes and the mechanical strength effect of this microstructure on the Triple Periotic Minimal Surfaces geometry. This new SSS approach is considered promising in industrial areas where innovative geometries can be produced with AM, weight-reduced designs using topology optimization, and DfAM (Design for Additive Manufacturing) are used.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":703,"journal":{"name":"Metals and Materials International","volume":"31 4","pages":"971 - 980"},"PeriodicalIF":3.3,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143667915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1007/s12540-024-01833-3
Jeong-In Kim, Sun-Joong Kim
Nonmetallic inclusions significantly affect the final quality of steel production. Mg-Al spinel inclusions, which are known for their high deformability, are particularly detrimental. Thus, controlling these favorable liquidus inclusions, such as Ca-Al inclusions, is crucial. The evolution of Ca-Al inclusions is primarily driven by the [Ca] source in molten steel, which is supplied by slag or the addition of Ca to the molten steel. Inclusions exhibit three physical behaviors: flotation into the slag, entrapment from the slag, and agglomeration within each inclusion. A numerical model grounded in a coupled reaction model was established to investigate these inclusion behaviors, with a focus on the evolution of the Ca-Al system inclusions. These findings indicate that the [Ca] concentration in molten steel drives the evolution of Ca-Al inclusions, but the rate of evolution is limited by the mass transfer rate of the Ca source into the inclusion. Moreover, slag composition, particularly the higher basicity and slags enriched with Ca sources, such as CaF2, significantly influence the inclusion composition, reaching a composition closer to the liquid phase. Additionally, it was found that the physical behavior of inclusions, particularly entrapment from slag, plays a crucial role in controlling the inclusion composition. This study further discusses methods for controlling the liquidus composition of inclusions.
{"title":"Numerical Evaluation for Influence of Ca Treatment and Slag Composition on Compositional Changes in Non-metallic Inclusion Using Coupled Reaction Model for Ladle Treatment","authors":"Jeong-In Kim, Sun-Joong Kim","doi":"10.1007/s12540-024-01833-3","DOIUrl":"10.1007/s12540-024-01833-3","url":null,"abstract":"<div><p>Nonmetallic inclusions significantly affect the final quality of steel production. Mg-Al spinel inclusions, which are known for their high deformability, are particularly detrimental. Thus, controlling these favorable liquidus inclusions, such as Ca-Al inclusions, is crucial. The evolution of Ca-Al inclusions is primarily driven by the [Ca] source in molten steel, which is supplied by slag or the addition of Ca to the molten steel. Inclusions exhibit three physical behaviors: flotation into the slag, entrapment from the slag, and agglomeration within each inclusion. A numerical model grounded in a coupled reaction model was established to investigate these inclusion behaviors, with a focus on the evolution of the Ca-Al system inclusions. These findings indicate that the [Ca] concentration in molten steel drives the evolution of Ca-Al inclusions, but the rate of evolution is limited by the mass transfer rate of the Ca source into the inclusion. Moreover, slag composition, particularly the higher basicity and slags enriched with Ca sources, such as CaF<sub>2</sub>, significantly influence the inclusion composition, reaching a composition closer to the liquid phase. Additionally, it was found that the physical behavior of inclusions, particularly entrapment from slag, plays a crucial role in controlling the inclusion composition. This study further discusses methods for controlling the liquidus composition of inclusions.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":703,"journal":{"name":"Metals and Materials International","volume":"30 12","pages":"3523 - 3536"},"PeriodicalIF":3.3,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1007/s12540-024-01817-3
Won-Bum Park, Chanumul Jung, Youn-Bae Kang
Sb is one of the tramp elements that remain in molten steel during the steelmaking process. It is generally known to be difficult to remove it from the molten steel. In order to develop a feasible process to remove Sb from molten steel, the evaporation reaction of Sb from molten steel was investigated by high-temperature liquid–gas experiments using an electromagnetic levitation melting technique and kinetic analysis. The evaporation rate of Sb was measured by varying the flow rate of incoming gas (Q), temperature (T), initial C content ([pct C](_0)), and initial S content ([pct S](_0)) in molten Fe–C–S–Sb alloys. It was found that the evaporation rate of Sb accelerated by S due to the formation of the sulfide gas species (SbS(g)) and by C due to increasing the activity coefficient of Sb ((f_{textrm{Sb}})) and S ((f_{text {S}})). On the other hand, the evaporation rate of Sb decelerated by S due to the blocking of the molten steel surface. Based on the established mechanism, a model of Sb evaporation from molten Fe–C–S–Sb alloy was developed in the present study, which considers (1) actual evaporating species, (2) surface blocking by S using ideal Langmuir adsorption, and (3) effect of C and temperature on (f_{text {Sb}}) and (f_{text {S}}). With the established model, the extent of Cu, Sn, and Sb removal in the molten steel was assessed. It turned out that Cu has the fastest removal rate, followed by Sb, with Sn being the slowest for molten steel containing 0.1 pct C and 0.01 pct S at 1650 (^circ )C.
{"title":"Modeling Evaporation of Sb from Molten Fe–C–S Alloys for Sustainable Steelmaking Supported by Experiment and Mechanisms Analysis","authors":"Won-Bum Park, Chanumul Jung, Youn-Bae Kang","doi":"10.1007/s12540-024-01817-3","DOIUrl":"10.1007/s12540-024-01817-3","url":null,"abstract":"<p> Sb is one of the tramp elements that remain in molten steel during the steelmaking process. It is generally known to be difficult to remove it from the molten steel. In order to develop a feasible process to remove Sb from molten steel, the evaporation reaction of Sb from molten steel was investigated by high-temperature liquid–gas experiments using an electromagnetic levitation melting technique and kinetic analysis. The evaporation rate of Sb was measured by varying the flow rate of incoming gas (<i>Q</i>), temperature (<i>T</i>), initial C content ([pct C]<span>(_0)</span>), and initial S content ([pct S]<span>(_0)</span>) in molten Fe–C–S–Sb alloys. It was found that the evaporation rate of Sb accelerated by S due to the formation of the sulfide gas species (SbS(g)) and by C due to increasing the activity coefficient of Sb (<span>(f_{textrm{Sb}})</span>) and S (<span>(f_{text {S}})</span>). On the other hand, the evaporation rate of Sb decelerated by S due to the blocking of the molten steel surface. Based on the established mechanism, a model of Sb evaporation from molten Fe–C–S–Sb alloy was developed in the present study, which considers (1) actual evaporating species, (2) surface blocking by S using ideal Langmuir adsorption, and (3) effect of C and temperature on <span>(f_{text {Sb}})</span> and <span>(f_{text {S}})</span>. With the established model, the extent of Cu, Sn, and Sb removal in the molten steel was assessed. It turned out that Cu has the fastest removal rate, followed by Sb, with Sn being the slowest for molten steel containing 0.1 pct C and 0.01 pct S at 1650 <span>(^circ )</span>C.</p>","PeriodicalId":703,"journal":{"name":"Metals and Materials International","volume":"30 12","pages":"3497 - 3512"},"PeriodicalIF":3.3,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1007/s12540-024-01820-8
Jaewoo Myung, Jiwon Park, Kyung-Ho Kim, Hiroyuki Shibata, Yunki Byeun, Yongsug Chung
A reaction mechanism is suggested for two types of MgAl2O4 refractories; a MgAl2O4 and a MgO-rich MgAl2O4, which were reacted with a liquid ferromanganese metal. The finger rotating test (FRT) technique was adopted and experiments were carried out at 1873 K. After the experiments, each refractory was analyzed by X-ray computed tomography, field emission scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. When the MgAl2O4 was in contact with the liquid ferromanganese metal, complex (Mg,Mn)(Mn,Al)2O4 layers were formed at the surface of the refractory. It acted as a passive layer since manganese ions did not penetrate into the bulk of the refractory with increasing reaction time. However, when the MgO-rich MgAl2O4 was in contact with liquid ferromanganese metal, manganese ions selectively penetrated through the MgO grains, which led to the formation of a (MgxMn1-x)O solid solution. The penetration depth increased both with increasing reaction time and rotating speed. The characteristics of the reaction layers were analyzed by XRD and EDX and, a possible mechanism to form these layers was suggested based on thermodynamic consideration.
{"title":"Reaction Mechanism of MgAl2O4 Refractories in Contact with a Liquid Ferromanganese Metal","authors":"Jaewoo Myung, Jiwon Park, Kyung-Ho Kim, Hiroyuki Shibata, Yunki Byeun, Yongsug Chung","doi":"10.1007/s12540-024-01820-8","DOIUrl":"10.1007/s12540-024-01820-8","url":null,"abstract":"<div><p>A reaction mechanism is suggested for two types of MgAl<sub>2</sub>O<sub>4</sub> refractories; a MgAl<sub>2</sub>O<sub>4</sub> and a MgO-rich MgAl<sub>2</sub>O<sub>4</sub>, which were reacted with a liquid ferromanganese metal. The finger rotating test (FRT) technique was adopted and experiments were carried out at 1873 K. After the experiments, each refractory was analyzed by X-ray computed tomography, field emission scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. When the MgAl<sub>2</sub>O<sub>4</sub> was in contact with the liquid ferromanganese metal, complex (Mg,Mn)(Mn,Al)<sub>2</sub>O<sub>4</sub> layers were formed at the surface of the refractory. It acted as a passive layer since manganese ions did not penetrate into the bulk of the refractory with increasing reaction time. However, when the MgO-rich MgAl<sub>2</sub>O<sub>4</sub> was in contact with liquid ferromanganese metal, manganese ions selectively penetrated through the MgO grains, which led to the formation of a (Mg<sub>x</sub>Mn<sub>1-x</sub>)O solid solution. The penetration depth increased both with increasing reaction time and rotating speed. The characteristics of the reaction layers were analyzed by XRD and EDX and, a possible mechanism to form these layers was suggested based on thermodynamic consideration.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><img></picture></div></div></figure></div></div>","PeriodicalId":703,"journal":{"name":"Metals and Materials International","volume":"30 12","pages":"3513 - 3522"},"PeriodicalIF":3.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1007/s12540-024-01796-5
Hongen An, Ismal Saad, Willey Liew Yun Hsien, Nancy Julius Siambun, Bih-Lii Chuab, Hongfu Wang
The experimental method employed the use of melt purification and cyclic superheating technique to achieve maximum undercooling of Ni65Cu31Co4 alloy at 300 K. Simultaneously, high-speed photography techniques were used to capture the process of alloy liquid phase interface migration, and analyze the relationship between the shape characteristics of the front end of alloy solidification and undercooling. The microstructure of the alloy was observed through metallographic microscopy, and the micro-morphological characteristics and evolution of the rapidly solidified microstructure were systematically studied. It was found that the grain refinement mechanism of Ni-Cu-Co ternary alloy is similar to that of Ni-Cu binary alloy. Grain refinement at low undercooling is caused by intense dendritic remelting, while grain refinement at high undercooling is attributed to recrystallization, driven by the stress and plastic strain accumulated from the interaction of liquid flow and primary dendrites caused by rapid solidification.
Graphical Abstract
{"title":"Microstructure Refinement in Solidification of a Deeply Undercooled Ternary Nickel Based Alloy","authors":"Hongen An, Ismal Saad, Willey Liew Yun Hsien, Nancy Julius Siambun, Bih-Lii Chuab, Hongfu Wang","doi":"10.1007/s12540-024-01796-5","DOIUrl":"10.1007/s12540-024-01796-5","url":null,"abstract":"<div><p>The experimental method employed the use of melt purification and cyclic superheating technique to achieve maximum undercooling of Ni65Cu31Co4 alloy at 300 K. Simultaneously, high-speed photography techniques were used to capture the process of alloy liquid phase interface migration, and analyze the relationship between the shape characteristics of the front end of alloy solidification and undercooling. The microstructure of the alloy was observed through metallographic microscopy, and the micro-morphological characteristics and evolution of the rapidly solidified microstructure were systematically studied. It was found that the grain refinement mechanism of Ni-Cu-Co ternary alloy is similar to that of Ni-Cu binary alloy. Grain refinement at low undercooling is caused by intense dendritic remelting, while grain refinement at high undercooling is attributed to recrystallization, driven by the stress and plastic strain accumulated from the interaction of liquid flow and primary dendrites caused by rapid solidification.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":703,"journal":{"name":"Metals and Materials International","volume":"31 4","pages":"1128 - 1136"},"PeriodicalIF":3.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143667852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Synergistic effect of Cr and Fe elements on stress corrosion fracture toughness of titanium alloy was analyzed by phase detection, observation of the microstructure, tensile mechanical properties test and stress corrosion fracture toughness test. TC4-Cr-Fe titanium alloy and TC4 titanium alloy were composed of α phase and β phase, and no other phases were detected. The microstructure characterization showed that the primary alpha phase (αp) and secondary alpha phase (αs) can be significantly refined due to the addition of Cr and Fe elements, and the formation of αs can be promoted. The tensile strength and stress corrosion fracture toughness can be improved by adding Cr and Fe elements. The synergistic effect of Cr and Fe elements on stress corrosion fracture toughness was that on the one hand, the formation of small angle grain boundaries can be promoted, which had a low diffusion rate and inhibited intergranular corrosion. On the other hand, TC4-Cr-Fe titanium alloy had a large number of αs aggregation regions in different directions, and at the same time, it had a higher proportion of schmid factor ≤ 0.3 in pyramidal slip system. Therefore, when the crack passes through, it will be frequently changed in direction, which has obvious retardation and deflection effect on the crack extension process. And when the grains with low schmid factor were penetrated by cracks, a large number of slip systems were difficult to start, resulting in stress concentration and dislocation density increase. The increase of dislocation density can effectively weaken the driving energy of micro-crack extension and increase the energy needed for its continuous extension, thus the crack extension process was hindered.
{"title":"Synergistic Effect of Cr and Fe Elements on Stress Corrosion Fracture Toughness of Titanium Alloy","authors":"Zhi-wei Lian, She-wei Xin, Ping Guo, Huan Wang, Fei Qiang, Xing-yang Tu, Hong-lin Fang","doi":"10.1007/s12540-024-01806-6","DOIUrl":"10.1007/s12540-024-01806-6","url":null,"abstract":"<div><p>Synergistic effect of Cr and Fe elements on stress corrosion fracture toughness of titanium alloy was analyzed by phase detection, observation of the microstructure, tensile mechanical properties test and stress corrosion fracture toughness test. TC4-Cr-Fe titanium alloy and TC4 titanium alloy were composed of α phase and β phase, and no other phases were detected. The microstructure characterization showed that the primary alpha phase (α<sub>p</sub>) and secondary alpha phase (α<sub>s</sub>) can be significantly refined due to the addition of Cr and Fe elements, and the formation of α<sub>s</sub> can be promoted. The tensile strength and stress corrosion fracture toughness can be improved by adding Cr and Fe elements. The synergistic effect of Cr and Fe elements on stress corrosion fracture toughness was that on the one hand, the formation of small angle grain boundaries can be promoted, which had a low diffusion rate and inhibited intergranular corrosion. On the other hand, TC4-Cr-Fe titanium alloy had a large number of α<sub>s</sub> aggregation regions in different directions, and at the same time, it had a higher proportion of schmid factor ≤ 0.3 in pyramidal slip system. Therefore, when the crack passes through, it will be frequently changed in direction, which has obvious retardation and deflection effect on the crack extension process. And when the grains with low schmid factor were penetrated by cracks, a large number of slip systems were difficult to start, resulting in stress concentration and dislocation density increase. The increase of dislocation density can effectively weaken the driving energy of micro-crack extension and increase the energy needed for its continuous extension, thus the crack extension process was hindered.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":703,"journal":{"name":"Metals and Materials International","volume":"31 4","pages":"1087 - 1095"},"PeriodicalIF":3.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143667850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1007/s12540-024-01805-7
Yingjie Wu, Riming Wu, Yafeng Zheng, Giselle Ramírez, Luis Llanes, Gege Huang, Yunpeng Zhao, Yaqing Yu, Kuicen Li, Yi Xu, Xuejun Jin
Die steels are conventionally used in forging, stamping, casting and injection and so on. Metallurgical elements in die steels like silicon, maganese, carbon and others radically decide the comprehensive properties. This paper has reviewed the current state of the art of silicon effect in die steels in terms of cementite growth, size and distribution of alloy carbides, thermal stability of retained austenite, tempering kinetics, and mechanical properties. Results exposed in different works indicated that silicon tends to segregate at the cementite-ferrite grain boundaries in high-silicon die steels, and the presence of this silicon-rich region effectively delays the formation of cementite. On the other hand, a lower silicon content distributes the carbides between the martensitic laths more uniformly and reduces the particle size to avoid the brittle intergranular fracture. Thus a reduction in the silicon content can significantly improve the toughness and tempering resistance, as well as effectively inhibit the retention of austenite to achieve better dimensional stability of dies. Finally, the obstructive effect of silicon on carbon atoms was verified using an isothermal carbon diffusion model.
Graphical Abstract
{"title":"Silicon in Die Steels","authors":"Yingjie Wu, Riming Wu, Yafeng Zheng, Giselle Ramírez, Luis Llanes, Gege Huang, Yunpeng Zhao, Yaqing Yu, Kuicen Li, Yi Xu, Xuejun Jin","doi":"10.1007/s12540-024-01805-7","DOIUrl":"10.1007/s12540-024-01805-7","url":null,"abstract":"<div><p>Die steels are conventionally used in forging, stamping, casting and injection and so on. Metallurgical elements in die steels like silicon, maganese, carbon and others radically decide the comprehensive properties. This paper has reviewed the current state of the art of silicon effect in die steels in terms of cementite growth, size and distribution of alloy carbides, thermal stability of retained austenite, tempering kinetics, and mechanical properties. Results exposed in different works indicated that silicon tends to segregate at the cementite-ferrite grain boundaries in high-silicon die steels, and the presence of this silicon-rich region effectively delays the formation of cementite. On the other hand, a lower silicon content distributes the carbides between the martensitic laths more uniformly and reduces the particle size to avoid the brittle intergranular fracture. Thus a reduction in the silicon content can significantly improve the toughness and tempering resistance, as well as effectively inhibit the retention of austenite to achieve better dimensional stability of dies. Finally, the obstructive effect of silicon on carbon atoms was verified using an isothermal carbon diffusion model.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":703,"journal":{"name":"Metals and Materials International","volume":"31 4","pages":"915 - 935"},"PeriodicalIF":3.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143667854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The trade-off relationship between strength and ductility severely constrains the potential applications of magnesium matrix composites (MMCs). In this work, nano-Cu particle reinforced AZ31 composites achieved simultaneous improvements in strength and ductility. Nano-Cu/AZ31 composites were prepared using a powder metallurgy method combined with hot extrusion. The results showed that the addition of nano-Cu particles refined the grains of the composites, increasing the probability of activation of the pyramidal slip system. The evolution of tiny secondary phases from Cu particles inhibited the dynamic recrystallization (DRX) behavior of the composites. The as-extruded 1 wt% Cu/AZ31 composites exhibited the best mechanical properties, with yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) reaching 223 MPa, 309 MPa, and 13.7%, respectively, representing enhancements of 21.9%, 11.2%, and 83% compared to the AZ31 matrix. The increase in strength originated from grain refinement, mismatch in thermal expansion coefficients, and Orowan strengthening, while the enhancement in ductility was attributed to the initiation of more slip systems and the synergistic effect of nano-Cu particles.
Graphical Abstract
{"title":"Effect of Nano-Cu Particles on the Microstructure and Mechanical Properties of Cu/AZ31 Composites","authors":"Jun Xia, Shenglin Liu, Pengfei Gao, Yuhui Zhang, Pengju Chen, Xiaohui Zhang, Tiegang Luo, Shengli Han, Kaihong Zheng","doi":"10.1007/s12540-024-01807-5","DOIUrl":"10.1007/s12540-024-01807-5","url":null,"abstract":"<div><p>The trade-off relationship between strength and ductility severely constrains the potential applications of magnesium matrix composites (MMCs). In this work, nano-Cu particle reinforced AZ31 composites achieved simultaneous improvements in strength and ductility. Nano-Cu/AZ31 composites were prepared using a powder metallurgy method combined with hot extrusion. The results showed that the addition of nano-Cu particles refined the grains of the composites, increasing the probability of activation of the pyramidal slip system. The evolution of tiny secondary phases from Cu particles inhibited the dynamic recrystallization (DRX) behavior of the composites. The as-extruded 1 wt% Cu/AZ31 composites exhibited the best mechanical properties, with yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) reaching 223 MPa, 309 MPa, and 13.7%, respectively, representing enhancements of 21.9%, 11.2%, and 83% compared to the AZ31 matrix. The increase in strength originated from grain refinement, mismatch in thermal expansion coefficients, and Orowan strengthening, while the enhancement in ductility was attributed to the initiation of more slip systems and the synergistic effect of nano-Cu particles.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":703,"journal":{"name":"Metals and Materials International","volume":"31 4","pages":"1152 - 1167"},"PeriodicalIF":3.3,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143667851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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