Pub Date : 2024-10-30DOI: 10.1016/j.msea.2024.147488
Ashok Bhadeliya , Birgit Rehmer , Bernard Fedelich , Torsten Jokisch , Birgit Skrotzki , Jürgen Olbricht
Gas turbine components made of nickel-based alloys can be repaired through diffusion brazing. However, process-induced imperfections, defects within the brazing zone, and material property mismatches between the braze alloy and base material may facilitate crack initiation and propagation, ultimately leading to early component failure. To gain insight into the crack growth mechanism and quantitatively characterize fatigue crack growth behavior within brazing zones, fatigue crack growth (FCG) experiments were conducted on brazed joint specimens of nickel-based alloy Alloy 247DS at a temperature of 950 °C and a stress ratio R = 0.1. The FCG tests were complemented by fractographic and microstructural analyses, to elucidate the relationship between crack growth mechanisms and the microstructure of the brazed joint. The results demonstrate stable crack propagation within the brazing zone and the nickel-based braze alloy. The latter contains brittle eutectic boride phases and intermetallic phases that reduce the resistance to crack propagation compared to the parent material. This study demonstrates the applicability of standard FCG experimental procedures to fusion zones, thereby enabling a preliminary understanding of crack growth behavior in brazing zones.
{"title":"Fatigue crack growth behavior of Alloy 247DS brazed joints at high temperatures","authors":"Ashok Bhadeliya , Birgit Rehmer , Bernard Fedelich , Torsten Jokisch , Birgit Skrotzki , Jürgen Olbricht","doi":"10.1016/j.msea.2024.147488","DOIUrl":"10.1016/j.msea.2024.147488","url":null,"abstract":"<div><div>Gas turbine components made of nickel-based alloys can be repaired through diffusion brazing. However, process-induced imperfections, defects within the brazing zone, and material property mismatches between the braze alloy and base material may facilitate crack initiation and propagation, ultimately leading to early component failure. To gain insight into the crack growth mechanism and quantitatively characterize fatigue crack growth behavior within brazing zones, fatigue crack growth (FCG) experiments were conducted on brazed joint specimens of nickel-based alloy Alloy 247DS at a temperature of 950 °C and a stress ratio R = 0.1. The FCG tests were complemented by fractographic and microstructural analyses, to elucidate the relationship between crack growth mechanisms and the microstructure of the brazed joint. The results demonstrate stable crack propagation within the brazing zone and the nickel-based braze alloy. The latter contains brittle eutectic boride phases and intermetallic phases that reduce the resistance to crack propagation compared to the parent material. This study demonstrates the applicability of standard FCG experimental procedures to fusion zones, thereby enabling a preliminary understanding of crack growth behavior in brazing zones.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"918 ","pages":"Article 147488"},"PeriodicalIF":6.1,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This investigation focuses on unravelling the dominant influence of microsegregation and microstructure altered due to heat treatment cycle variation on creep rupture behaviour of additively manufactured Inconel 718 (AM-IN718). Two microstructural variants differing in the fraction of recrystallized grains while -phase being absent, were produced. A typical heat treatment (HT) cycle includes the stress-relieving of the as-built specimens at 980 °C, followed by solution treatment at 1080 °C (STA1080, a partially recrystallized microstructural variant) or 1150 °C (STA1150, a fully recrystallized microstructural variant), and double ageing (soaking at 720 °C for 8h and subsequent furnace cooling, followed by 8h at 620 °C and air cooling).
Detailed microstructural characterization of two microstructural variants through correlative microscopy revealed a prevalent existence of Nb-rich precipitate-free zones (PFZ) in STA1080 than in STA1150. Creep characterization of the two microstructural variants in the temperature range of 625–675 °C and at 500–750 MPa demonstrated superior creep resistance in STA1150. The correlation of kinetic analysis and comprehensive post-deformation microstructural characterization suggests grain boundary cavitation as the main damage/softening mechanism and the reason for the difference in creep rupture behaviour between the two microstructural variants. The long-term exposure heat treatment methodology demonstrates that PFZs are the major influencing factor responsible for microsegregation-dependent creep rupture behaviour. Interestingly, the presence of the phase within PFZs appeared to retard cavity coalescence and failure during creep, despite its usual detrimental role in creep resistance.
{"title":"Unravelling the dominant influence of microsegregation on creep rupture behaviour of additively manufactured inconel 718","authors":"Singaravelu Rajan Sabari , N.T.B.N. Koundinya , Akshat Godha , Surendra Kumar Makineni , S.V.S. Narayana Murty , B.K. Nagesha , G.D. Janaki Ram , Ravi Sankar Kottada","doi":"10.1016/j.msea.2024.147480","DOIUrl":"10.1016/j.msea.2024.147480","url":null,"abstract":"<div><div>This investigation focuses on unravelling the dominant influence of microsegregation and microstructure altered due to heat treatment cycle variation on creep rupture behaviour of additively manufactured Inconel 718 (AM-IN718). Two microstructural variants differing in the fraction of recrystallized grains while <span><math><mrow><mi>δ</mi></mrow></math></span>-phase being absent, were produced. A typical heat treatment (HT) cycle includes the stress-relieving of the as-built specimens at 980 °C, followed by solution treatment at 1080 °C (STA1080, a partially recrystallized microstructural variant) or 1150 °C (STA1150, a fully recrystallized microstructural variant), and double ageing (soaking at 720 °C for 8h and subsequent furnace cooling, followed by 8h at 620 °C and air cooling).</div><div>Detailed microstructural characterization of two microstructural variants through correlative microscopy revealed a prevalent existence of Nb-rich precipitate-free zones (PFZ) in STA1080 than in STA1150. Creep characterization of the two microstructural variants in the temperature range of 625–675 °C and at 500–750 MPa demonstrated superior creep resistance in STA1150. The correlation of kinetic analysis and comprehensive post-deformation microstructural characterization suggests grain boundary cavitation as the main damage/softening mechanism and the reason for the difference in creep rupture behaviour between the two microstructural variants. The long-term exposure heat treatment methodology demonstrates that PFZs are the major influencing factor responsible for microsegregation-dependent creep rupture behaviour. Interestingly, the presence of the <span><math><mrow><mi>δ</mi></mrow></math></span> phase within PFZs appeared to retard cavity coalescence and failure during creep, despite its usual detrimental role in creep resistance.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"919 ","pages":"Article 147480"},"PeriodicalIF":6.1,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-30DOI: 10.1016/j.msea.2024.147430
Chao Fang , Jianke Qiu , Mingjie Zhang , Mengmeng Zhang , Yingjie Ma , Jiafeng Lei , Rui Yang
In this work, the dwell sensitivity of the TC11 alloy was evaluated as a function of αp contents obtained by two different heat treatment routes and peak applied stresses. The equiaxed microstructure had higher αp content and sharper macrozones, with consequently exhibiting higher dwell sensitivity than the bimodal microstructure. In order to elucidate the dwell fatigue cracking mechanism, the electron back-scattering diffraction and quantitative tilt fractography techniques were employed to determine the crystallographic and spatial orientations of the facets on the fractures. The results indicated that the initiation facets nearly cracked along the basal plane, whereas the propagation facets deviated from the basal plane with an average angle of ∼13° for both microstructures. Based on the measurements of the facet orientation, a method was proposed that the macrozone filtered with a threshold of 35° could be used as a reliable microstructure characteristic for assessing the dwell sensitivity and predicting the crack initiation sites in TC11 alloy. Specifically, a basal plane of soft-oriented grain in this hard macrozone, which had the largest c-axis inclination and basal Schmid factor compared to its surrounding grains, was more prone to the crack initiation.
{"title":"Investigation on the dwell fatigue behavior of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy","authors":"Chao Fang , Jianke Qiu , Mingjie Zhang , Mengmeng Zhang , Yingjie Ma , Jiafeng Lei , Rui Yang","doi":"10.1016/j.msea.2024.147430","DOIUrl":"10.1016/j.msea.2024.147430","url":null,"abstract":"<div><div>In this work, the dwell sensitivity of the TC11 alloy was evaluated as a function of α<sub>p</sub> contents obtained by two different heat treatment routes and peak applied stresses. The equiaxed microstructure had higher α<sub>p</sub> content and sharper macrozones, with consequently exhibiting higher dwell sensitivity than the bimodal microstructure. In order to elucidate the dwell fatigue cracking mechanism, the electron back-scattering diffraction and quantitative tilt fractography techniques were employed to determine the crystallographic and spatial orientations of the facets on the fractures. The results indicated that the initiation facets nearly cracked along the basal plane, whereas the propagation facets deviated from the basal plane with an average angle of ∼13° for both microstructures. Based on the measurements of the facet orientation, a method was proposed that the macrozone filtered with a threshold of 35° could be used as a reliable microstructure characteristic for assessing the dwell sensitivity and predicting the crack initiation sites in TC11 alloy. Specifically, a basal plane of soft-oriented grain in this hard macrozone, which had the largest c-axis inclination and basal Schmid factor compared to its surrounding grains, was more prone to the crack initiation.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"918 ","pages":"Article 147430"},"PeriodicalIF":6.1,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-10-30DOI: 10.1016/j.msea.2024.147479
Kaige Wang , Jifeng Yang , Weichang Wei , Guangcheng Xiao , Zhe Yuan , Ligang Zhang , Libin Liu
In the present work, the influence of β grain size on stress-induced martensite (SIM) was investigated in a metastable β-Ti alloy (Ti-4Mo-3Cr-1Fe-1Al). Samples with varying grain sizes were prepared by cold rolling and annealing. The triggering stress for SIM decreases with the grain size increase from 44 μm to 180 μm. Meanwhile, the yield strength increases with decreasing grain size, consistent with the Hall-Petch effect. Fine-grained samples formed a greater number of martensitic bands during deformation compared to coarse-grained samples, resulting in an ultra-high strain-hardening rate ∼4320 MPa. The deformation mechanism of the Ti-4Mo-3Cr-1Fe-1Al alloy consists of the ω to β transformation, SIM, martensite deformation twinning ({110}cc < 1–10>α" and {130}<-310>α" twins), reorientation of martensite and dislocation slip. Both the 44 μm and 59 μm samples exhibit ultra-high true tensile strengths (>1200 MPa), with a large work-hardening interval of nearly 600 MPa relative to the yield strength. This significant work-hardening capability is attributed to interfacial and dislocation strengthening arising from the dynamic formation of martensitic bands during deformation.
{"title":"Grain size effect on stress-induced martensite in a metastable β-Ti alloy with ultrahigh strength and strain hardening rate","authors":"Kaige Wang , Jifeng Yang , Weichang Wei , Guangcheng Xiao , Zhe Yuan , Ligang Zhang , Libin Liu","doi":"10.1016/j.msea.2024.147479","DOIUrl":"10.1016/j.msea.2024.147479","url":null,"abstract":"<div><div>In the present work, the influence of β grain size on stress-induced martensite (SIM) was investigated in a metastable β-Ti alloy (Ti-4Mo-3Cr-1Fe-1Al). Samples with varying grain sizes were prepared by cold rolling and annealing. The triggering stress for SIM decreases with the grain size increase from 44 μm to 180 μm. Meanwhile, the yield strength increases with decreasing grain size, consistent with the Hall-Petch effect. Fine-grained samples formed a greater number of martensitic bands during deformation compared to coarse-grained samples, resulting in an ultra-high strain-hardening rate ∼4320 MPa. The deformation mechanism of the Ti-4Mo-3Cr-1Fe-1Al alloy consists of the ω to β transformation, SIM, martensite deformation twinning ({110}cc < 1–10><sub>α</sub>\" and {130}<-310><sub>α</sub>\" twins), reorientation of martensite and dislocation slip. Both the 44 μm and 59 μm samples exhibit ultra-high true tensile strengths (>1200 MPa), with a large work-hardening interval of nearly 600 MPa relative to the yield strength. This significant work-hardening capability is attributed to interfacial and dislocation strengthening arising from the dynamic formation of martensitic bands during deformation.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"918 ","pages":"Article 147479"},"PeriodicalIF":6.1,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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: 10.1016/j.msea.2024.147478
A.V. Shuitcev , Y. Ren , D.V. Gunderov , R.N. Vasin , L. Li , R.Z. Valiev , Y.F. Zheng , Y.X. Tong
Grain refinement and precipitation hardening play critical important role for stabilization and improving functional properties of shape memory alloys. However, the relationship between precipitation and nanocrystalline grain growth behavior in NiTiHf alloys is still unclear. This work aims to investigate the role of precipitation in the nanocrystalline grain growth behavior of HPT-processed Ni50Ti30Hf20 high-temperature shape memory alloy. An abnormally low grain growth rate (n = 0.08) was observed after post-deformation annealing (PDA) at 550 °C for 1 h. It was proposed that grain growth suppression may be caused by the presence of relatively large H-phase precipitates, which act as barriers to grain boundary movement. A detailed analysis of the grain growth kinetics during PDA suggests that the coarsening process is controlled by Ni diffusion. Additionally, the dependence of strength and transformation temperatures on grain size in NiTiHf alloy is found to follow the Hall-Petch relation with some exceptions due to H-phase precipitation. The results of this research may be useful for the development of methods and strategies to stabilize the nanocrystalline structure in metallic materials.
晶粒细化和沉淀硬化对稳定和改善形状记忆合金的功能特性起着至关重要的作用。然而，镍钛铪合金中沉淀与纳米晶粒生长行为之间的关系仍不清楚。本研究旨在探讨析出在 HPT 加工的 Ni50Ti30Hf20 高温形状记忆合金的纳米晶晶粒生长行为中的作用。在 550 °C 下进行 1 小时的形变后退火（PDA）后，观察到异常低的晶粒生长率（n = 0.08）。研究人员提出，晶粒生长受抑制可能是由于存在相对较大的 H 相沉淀物，这些沉淀物阻碍了晶界运动。对 PDA 过程中晶粒生长动力学的详细分析表明，粗化过程是由镍扩散控制的。此外，还发现镍钛铪合金的强度和转变温度与晶粒大小的关系遵循霍尔-佩奇关系，但由于 H 相析出的缘故，存在一些例外情况。这项研究的结果可能有助于开发稳定金属材料中纳米晶结构的方法和策略。
{"title":"Grain growth in Ni50Ti30Hf20 high-temperature shape memory alloy processed by high-pressure torsion","authors":"A.V. Shuitcev , Y. Ren , D.V. Gunderov , R.N. Vasin , L. Li , R.Z. Valiev , Y.F. Zheng , Y.X. Tong","doi":"10.1016/j.msea.2024.147478","DOIUrl":"10.1016/j.msea.2024.147478","url":null,"abstract":"<div><div>Grain refinement and precipitation hardening play critical important role for stabilization and improving functional properties of shape memory alloys. However, the relationship between precipitation and nanocrystalline grain growth behavior in NiTiHf alloys is still unclear. This work aims to investigate the role of precipitation in the nanocrystalline grain growth behavior of HPT-processed Ni<sub>50</sub>Ti<sub>30</sub>Hf<sub>20</sub> high-temperature shape memory alloy. An abnormally low grain growth rate (<em>n</em> = 0.08) was observed after post-deformation annealing (PDA) at 550 °C for 1 h. It was proposed that grain growth suppression may be caused by the presence of relatively large H-phase precipitates, which act as barriers to grain boundary movement. A detailed analysis of the grain growth kinetics during PDA suggests that the coarsening process is controlled by Ni diffusion. Additionally, the dependence of strength and transformation temperatures on grain size in NiTiHf alloy is found to follow the Hall-Petch relation with some exceptions due to H-phase precipitation. The results of this research may be useful for the development of methods and strategies to stabilize the nanocrystalline structure in metallic materials.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"918 ","pages":"Article 147478"},"PeriodicalIF":6.1,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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: 10.1016/j.msea.2024.147487
Jong Woo Won , Jeong Mok Oh , Woo Chul Kim , Chan Hee Park , Ihho Park , Yong-Taek Hyun
Addition of ∼3 wt% Ce to cast pure Ti induced formation of numerous fine Ce particles on the microstructure. The Ce-alloyed cast Ti had both high tensile strength and ductility, which are unattainable simultaneously in cast pure Ti. The mechanisms by which the Ce particles increased tensile properties were identified.
在纯钛铸件中加入 ∼3 wt% 的 Ce 会在微观结构中形成大量细小的 Ce 颗粒。Ce合金化的铸造钛同时具有高抗拉强度和延展性，这是铸造纯钛无法同时达到的。确定了 Ce 粒子提高拉伸性能的机制。
{"title":"Simultaneous high tensile strength and high ductility in cast Ce-alloyed Ti","authors":"Jong Woo Won , Jeong Mok Oh , Woo Chul Kim , Chan Hee Park , Ihho Park , Yong-Taek Hyun","doi":"10.1016/j.msea.2024.147487","DOIUrl":"10.1016/j.msea.2024.147487","url":null,"abstract":"<div><div>Addition of ∼3 wt% Ce to cast pure Ti induced formation of numerous fine Ce particles on the microstructure. The Ce-alloyed cast Ti had both high tensile strength and ductility, which are unattainable simultaneously in cast pure Ti. The mechanisms by which the Ce particles increased tensile properties were identified.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"918 ","pages":"Article 147487"},"PeriodicalIF":6.1,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1016/j.msea.2024.147485
Zhenxiong Wei , Peng Huang , Xixi Su , Qiang Gao , Zhanhao Feng , Lin Peng , Jun Li , Guoyin Zu
This study investigates the effect of bell annealing (600 °C–750 °C/3 h–15 h) on the interfacial microstructure and mechanical characteristics of hot-rolled titanium/steel (Ti/steel) bi-metallic plates, aiming to improve their mechanical performance and deformation compatibility. The interfacial bonding mechanism and growth process of the interfacial TiC layer were studied using multi-scale characterization. The microstructural evolution during annealing and the effect of the TiC layer on element interdiffusion were considered. Results show that the TiC interlayer inhibits Ti and Fe diffusion, preventing undesirable Ti-Fe phases, and the TiC layer thickens towards the Ti side. Higher annealing temperatures and longer times worsened the grain size difference between the Ti and steel layers and produced a thick TiC layer, severely degrading deformation compatibility. Microcracks, caused by severe lattice mismatch, are mostly initial at the α-Fe/TiC interface during plastic deformation. Thin to moderate TiC layers resulted in a combination of ductile and brittle fractures, while thick layers led to brittle fractures. In terms of mechanical properties, the ultimate tensile strength (UTS), yield strength (YS), shear strength, and elongation (EL) of the hot-rolled composite plate were measured at 337 MPa, 232 MPa, 238 MPa, and 29 %, respectively. All annealed samples exhibited a reduction in UTS, YS, and shear strength compared to the hot-rolled state; however, they demonstrated improved EL and deformation compatibility, with the elongation achieving its optimal value at 650 °C-3 h. The annealing, at 650 °C for 3 h, was identified as the optimal condition for post-rolling heat treatment, resulting in a composite plate with a comprehensive mechanical performance characterized by UTS, YS, shear strength, and EL values of 267 MPa, 127 MPa, 171 MPa, and 46 %, respectively.
{"title":"Effect of bell annealing on the interface microstructure and mechanical properties of titanium/steel composite plates prepared by hot rolling","authors":"Zhenxiong Wei , Peng Huang , Xixi Su , Qiang Gao , Zhanhao Feng , Lin Peng , Jun Li , Guoyin Zu","doi":"10.1016/j.msea.2024.147485","DOIUrl":"10.1016/j.msea.2024.147485","url":null,"abstract":"<div><div>This study investigates the effect of bell annealing (600 °C–750 °C/3 h–15 h) on the interfacial microstructure and mechanical characteristics of hot-rolled titanium/steel (Ti/steel) bi-metallic plates, aiming to improve their mechanical performance and deformation compatibility. The interfacial bonding mechanism and growth process of the interfacial TiC layer were studied using multi-scale characterization. The microstructural evolution during annealing and the effect of the TiC layer on element interdiffusion were considered. Results show that the TiC interlayer inhibits Ti and Fe diffusion, preventing undesirable Ti-Fe phases, and the TiC layer thickens towards the Ti side. Higher annealing temperatures and longer times worsened the grain size difference between the Ti and steel layers and produced a thick TiC layer, severely degrading deformation compatibility. Microcracks, caused by severe lattice mismatch, are mostly initial at the α-Fe/TiC interface during plastic deformation. Thin to moderate TiC layers resulted in a combination of ductile and brittle fractures, while thick layers led to brittle fractures. In terms of mechanical properties, the ultimate tensile strength (UTS), yield strength (YS), shear strength, and elongation (EL) of the hot-rolled composite plate were measured at 337 MPa, 232 MPa, 238 MPa, and 29 %, respectively. All annealed samples exhibited a reduction in UTS, YS, and shear strength compared to the hot-rolled state; however, they demonstrated improved EL and deformation compatibility, with the elongation achieving its optimal value at 650 °C-3 h. The annealing, at 650 °C for 3 h, was identified as the optimal condition for post-rolling heat treatment, resulting in a composite plate with a comprehensive mechanical performance characterized by UTS, YS, shear strength, and EL values of 267 MPa, 127 MPa, 171 MPa, and 46 %, respectively.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"919 ","pages":"Article 147485"},"PeriodicalIF":6.1,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142656838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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: 10.1016/j.msea.2024.147465
Chunliang Mao , Hanghang Cao , Xiangyu Xie , Chenxi Liu , Shengxiang Wang , Jianbo Jia , Jinlong Du , Zhiqing Lv , Junting Luo , Yongchang Liu
This study investigated the morphological evolution behaviors and the mechanical property of the weld interface during explosive welding for the flyer plate and base plate sourcing from the same reduced activation ferrite/martensitic (RAFM) steel. The relationship between fine-grain formation and the occurrence of dynamic recrystallization was analyzed based on the strain and temperature field distributions at the explosive-weld interface. Although post-weld tempering (PWT) treatment eliminated bent martensite laths, but it did not eliminate fine equiaxed grains and δ ferrite grains near the explosive-weld interface; therefore, the PWT treatment improved the mechanical properties of the explosive-weld RAFM steel joint only minimally. However, implementation of a normalizing process after the explosive welding process (“PWN” treatment) significantly eliminated the gradient structure and the residual δ ferrite grains at the explosive-weld interface of the RAFM steel joint. Based on the PWN state, the inclusion of a tempering treatment (“PWNT” treatment) promoted the uniform precipitation of M23C6 carbides, which significantly improved the tensile strengths of the explosive-weld RAFM steel specimens under both room and high temperatures. To study the influence of different microstructures on the plastic deformation behavior at the explosive-weld interface, the representative volume element (RVE) models basing on crystal plasticity finite element (CPFEM) method was constructed for different post-weld heat treatments (PWHTs). At the explosive-weld interface of the PWT-state RAFM steel joint, the plastic deformation was mainly concentrated in the δ ferrite grains, rather than in the fine equiaxed grains. In addition, only minimal deformation concentration was observed for the PWNT-state RAFM steel joint. In order to reveal the independent influence of the fine equiaxed grains at the weld interface on the mechanical properties of explosive-weld RAFM steel joint, the microstructural and mechanical distinctions between the RAFM steel joints in the N-PWT and PWNT states were investigated detailly. Finally, through optimization of the PWHT method, an explosive-weld RAFM steel (PWNT state) joint with a uniform microstructure and ideal mechanical properties was obtained.
{"title":"Microstructure and mechanical-property evolution of the explosive welding joint from the same RAFM steels under explosive welding and post-weld heat treatment","authors":"Chunliang Mao , Hanghang Cao , Xiangyu Xie , Chenxi Liu , Shengxiang Wang , Jianbo Jia , Jinlong Du , Zhiqing Lv , Junting Luo , Yongchang Liu","doi":"10.1016/j.msea.2024.147465","DOIUrl":"10.1016/j.msea.2024.147465","url":null,"abstract":"<div><div>This study investigated the morphological evolution behaviors and the mechanical property of the weld interface during explosive welding for the flyer plate and base plate sourcing from the same reduced activation ferrite/martensitic (RAFM) steel. The relationship between fine-grain formation and the occurrence of dynamic recrystallization was analyzed based on the strain and temperature field distributions at the explosive-weld interface. Although post-weld tempering (PWT) treatment eliminated bent martensite laths, but it did not eliminate fine equiaxed grains and δ ferrite grains near the explosive-weld interface; therefore, the PWT treatment improved the mechanical properties of the explosive-weld RAFM steel joint only minimally. However, implementation of a normalizing process after the explosive welding process (“PWN” treatment) significantly eliminated the gradient structure and the residual δ ferrite grains at the explosive-weld interface of the RAFM steel joint. Based on the PWN state, the inclusion of a tempering treatment (“PWNT” treatment) promoted the uniform precipitation of M<sub>23</sub>C<sub>6</sub> carbides, which significantly improved the tensile strengths of the explosive-weld RAFM steel specimens under both room and high temperatures. To study the influence of different microstructures on the plastic deformation behavior at the explosive-weld interface, the representative volume element (RVE) models basing on crystal plasticity finite element (CPFEM) method was constructed for different post-weld heat treatments (PWHTs). At the explosive-weld interface of the PWT-state RAFM steel joint, the plastic deformation was mainly concentrated in the δ ferrite grains, rather than in the fine equiaxed grains. In addition, only minimal deformation concentration was observed for the PWNT-state RAFM steel joint. In order to reveal the independent influence of the fine equiaxed grains at the weld interface on the mechanical properties of explosive-weld RAFM steel joint, the microstructural and mechanical distinctions between the RAFM steel joints in the N-PWT and PWNT states were investigated detailly. Finally, through optimization of the PWHT method, an explosive-weld RAFM steel (PWNT state) joint with a uniform microstructure and ideal mechanical properties was obtained.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"918 ","pages":"Article 147465"},"PeriodicalIF":6.1,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A combinatorial experimental and multi-scale simulations study has been performed to understand the role of microstructural heterogeneity on the deformation behaviour of a copper plate with a gradient layer produced by the surface mechanical grinding treatment (SMGT). Finite element analysis was employed to estimate the deformation during the SMGT process. Electron back scatter diffraction analysis indicated shear-type texture at all locations across thickness along with a continuous gradient of geometrically necessary dislocation (GND) density, resulting in an increasing trend of hardness from 81 ± 3 HV at the bottom to 119 ± 1 HV at the top. The SMGT samples showed ∼22 % improvement in yield and tensile strength with comparable ductility compared to the base material. Full field crystal plasticity simulations using the Dusseldorf Advanced Materials Simulation Kit (DAMASK) successfully captured the global stress-strain response, texture evolution, and multi-length scale stress-strain partitioning along the thickness during tensile deformation. The improvement in the yield strength of the SMGT samples was attributed to dislocation strengthening and grain size strengthening while the strain hardening behaviour was explained by the presence of higher GNDs in the SMGT sample compared to the base metal. Thus, a robust process-microstructure-mechanical property paradigm has been established for the SMGT copper.
{"title":"A finite element method and fast Fourier transform based crystal plasticity simulations study on the evolution of microstructure and mechanical properties of gradient structure copper","authors":"Deepak Paliwal , Saroj Kumar Basantia , Manasij Yadava , N.P. Gurao","doi":"10.1016/j.msea.2024.147472","DOIUrl":"10.1016/j.msea.2024.147472","url":null,"abstract":"<div><div>A combinatorial experimental and multi-scale simulations study has been performed to understand the role of microstructural heterogeneity on the deformation behaviour of a copper plate with a gradient layer produced by the surface mechanical grinding treatment (SMGT). Finite element analysis was employed to estimate the deformation during the SMGT process. Electron back scatter diffraction analysis indicated shear-type texture at all locations across thickness along with a continuous gradient of geometrically necessary dislocation (GND) density, resulting in an increasing trend of hardness from 81 ± 3 HV at the bottom to 119 ± 1 HV at the top. The SMGT samples showed ∼22 % improvement in yield and tensile strength with comparable ductility compared to the base material. Full field crystal plasticity simulations using the Dusseldorf Advanced Materials Simulation Kit (DAMASK) successfully captured the global stress-strain response, texture evolution, and multi-length scale stress-strain partitioning along the thickness during tensile deformation. The improvement in the yield strength of the SMGT samples was attributed to dislocation strengthening and grain size strengthening while the strain hardening behaviour was explained by the presence of higher GNDs in the SMGT sample compared to the base metal. Thus, a robust process-microstructure-mechanical property paradigm has been established for the SMGT copper.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"919 ","pages":"Article 147472"},"PeriodicalIF":6.1,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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: 10.1016/j.msea.2024.147486
Qingkai Shen, Jiaxiang Xue, Zehong Zheng, Xiaoyan Yu, Ning Ou
High-entropy alloys (HEAs) have great potential for application in various fields due to their excellent performance. However, there are few reports on wire arc additive manufacturing of HEAs. In this study, CoCrFeNiMo0.2 HEA solid wire was prepared and used for WAAM based on cold metal transfer for the first time. Different deposition strategies (namely single-pass (SP), oscillation (OS), and multi-parallel pass (MPP)) were used to prepare metal wall samples of different thicknesses. The HEA samples' microstructure with different deposition strategies were explored by optical and scanning electron microscopy, as well as the electron backscatter diffraction method. Microhardness and tensile tests were used to evaluate the mechanical properties of different samples. The results prove that SP and MPP samples exhibit rougher surfaces due to heat accumulation. The OS sample has the best molding and an effective deposition ratio of up to 91.5 %. The composition of columnar grain grown along the deposition direction with strong {100}<001> cubic texture in both SP and OS samples. Therefore, these two samples have similar mechanical properties, and the mechanical performance in the vertical direction is better than that in the horizontal direction. Due to the complex internal thermal effects and remelting effects between welds, the internal structure of the MPP sample exhibits no obvious preferred orientation. Therefore, the anisotropy of mechanical properties is significantly alleviated.
高熵合金（HEAs）因其优异的性能，在各个领域都有着巨大的应用潜力。然而，有关线弧增材制造高熵合金的报道却很少。本研究首次制备了 CoCrFeNiMo0.2 HEA 实体线材，并将其用于基于冷金属转移的 WAAM。采用不同的沉积策略（即单程沉积（SP）、振荡沉积（OS）和多程平行沉积（MPP））制备了不同厚度的金属壁样品。采用光学显微镜、扫描电子显微镜和电子反向散射衍射法研究了不同沉积策略下 HEA 样品的微观结构。显微硬度和拉伸试验用于评估不同样品的机械性能。结果证明，SP 和 MPP 样品由于热量积聚，表面更粗糙。OS 样品的成型效果最好，有效沉积率高达 91.5%。在 SP 和 OS 样品中，柱状晶粒沿沉积方向生长，具有强烈的{100}<001>立方体纹理。因此，这两种样品具有相似的机械性能，且垂直方向的机械性能优于水平方向。由于复杂的内部热效应和焊缝间的重熔效应，MPP 样品的内部结构没有表现出明显的优先取向。因此，机械性能的各向异性得到明显缓解。
{"title":"Effects of deposition strategies on microstructure and mechanical properties of wire arc additive manufactured CoCrFeNiMo0.2 high-entropy alloy","authors":"Qingkai Shen, Jiaxiang Xue, Zehong Zheng, Xiaoyan Yu, Ning Ou","doi":"10.1016/j.msea.2024.147486","DOIUrl":"10.1016/j.msea.2024.147486","url":null,"abstract":"<div><div>High-entropy alloys (HEAs) have great potential for application in various fields due to their excellent performance. However, there are few reports on wire arc additive manufacturing of HEAs. In this study, CoCrFeNiMo<sub>0.2</sub> HEA solid wire was prepared and used for WAAM based on cold metal transfer for the first time. Different deposition strategies (namely single-pass (SP), oscillation (OS), and multi-parallel pass (MPP)) were used to prepare metal wall samples of different thicknesses. The HEA samples' microstructure with different deposition strategies were explored by optical and scanning electron microscopy, as well as the electron backscatter diffraction method. Microhardness and tensile tests were used to evaluate the mechanical properties of different samples. The results prove that SP and MPP samples exhibit rougher surfaces due to heat accumulation. The OS sample has the best molding and an effective deposition ratio of up to 91.5 %. The composition of columnar grain grown along the deposition direction with strong {100}<001> cubic texture in both SP and OS samples. Therefore, these two samples have similar mechanical properties, and the mechanical performance in the vertical direction is better than that in the horizontal direction. Due to the complex internal thermal effects and remelting effects between welds, the internal structure of the MPP sample exhibits no obvious preferred orientation. Therefore, the anisotropy of mechanical properties is significantly alleviated.</div></div>","PeriodicalId":385,"journal":{"name":"Materials Science and Engineering: A","volume":"918 ","pages":"Article 147486"},"PeriodicalIF":6.1,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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