AMI: Acta Materialia最新文献_第6页

Microstructural and Mechanical Characteristics in Ni-Mn-Ga Alloys Under a Magnetic Field-Assisted Directional Solidification Ni-Mn-Ga合金在磁场辅助定向凝固下的组织和力学特性

AMI: Acta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3892169

L. Hou, Siyuan Yang, Xingfu Yu, Y. Fautrelle, Zongbin Li, D. Cong, Z. Ren, Yanyan Zhu, Xi Li

{"title":"Microstructural and Mechanical Characteristics in Ni-Mn-Ga Alloys Under a Magnetic Field-Assisted Directional Solidification","authors":"L. Hou, Siyuan Yang, Xingfu Yu, Y. Fautrelle, Zongbin Li, D. Cong, Z. Ren, Yanyan Zhu, Xi Li","doi":"10.2139/ssrn.3892169","DOIUrl":"https://doi.org/10.2139/ssrn.3892169","url":null,"abstract":"In the present work, the effect of a transverse magnetic field-assisted directional solidification (MFADS) on the microstructures in Ni-Mn-Ga alloys has been investigated. The results show that the magnetic field is capable of inducing transversal macro segregation perpendicular to magnetic field, causing the emergence of martensite clusters in austenite matrix. Moreover, the magnetic field alleviates the micro segregation on a dendritic scale and promotes the preferred growth of austenite dendrites. On the basis of above investigation, several special samples are designed using the MFADS to study the crystallographic evolution and mechanical behavior during thermal/stress induced martensite transformation. The martensite cluster in austenite matrix is used to investigate the martensite transformation and growth under cooling-heating cycles. The crystallographic relationship and phase boundary microstructure between martensite and austenite have been characterized. In addition, the micro segregation on a dendritic scale can significantly influence the martensite variant distribution, corresponding to the performance during compressive circles based on the analysis about deformation gradient tensor. The stress-induced super elasticity is closely dependent on orientation, well explained from the perspective of different resolved shear stress factors and correspondence variant pair formation transformation strain. The crystallographic evolution has been characterized during in-situ stress-induced transformation. The findings not only deepen the understanding of martensite transformation and mechanical behavior under a thermal/stress field in Ni-Mn-Ga alloys, but also propose a promising strategy to obtain microstructure-controllable functional alloys by MFADS.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89089398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Non-Equilibrium Solidification Behavior With Solute Trapping Associated With Powder Characteristics During Electron Beam Additive Manufacturing 电子束增材制造过程中与粉末特性相关的溶质俘获非平衡凝固行为

AMI: Acta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3866407

Yufan Zhao, Huakang Bian, Hao Wang, K. Aoyagi, Yujie Cui, Y. Lei, K. Yamanaka, A. Chiba

{"title":"Non-Equilibrium Solidification Behavior With Solute Trapping Associated With Powder Characteristics During Electron Beam Additive Manufacturing","authors":"Yufan Zhao, Huakang Bian, Hao Wang, K. Aoyagi, Yujie Cui, Y. Lei, K. Yamanaka, A. Chiba","doi":"10.2139/ssrn.3866407","DOIUrl":"https://doi.org/10.2139/ssrn.3866407","url":null,"abstract":"For components built by powder bed fusion with electron beam (PBF-EB), the resulting microstructure arising from non-equilibrium solidification–microsegregation and the formation of interdendritic phases significantly affects the mechanical properties and hot cracking resistance. Notably, the powder characteristics influence heat absorption and conduction, thereby altering the molten pool behavior and solidification parameters. However, the effect of powder feedstock on non-equilibrium solidification during PBF has not been widely investigated. In this study, a CoCrMo alloy was built using powders prepared by gas-atomization (GA) and plasma rotating electrode process (PREP). Under the given operating conditions, the samples built with the two powders were experimentally characterized and their compression properties were compared. By performing multi-scale numerical simulations, powder melting and solidification were visualized and analyzed to elucidate the mechanism through which the powder characteristics influence the non-equilibrium solidification behavior during PBF-EB. The study revealed that upon appropriated size control, compared to the GA powder, the PREP powder had a smaller specific surface area and higher sphericity; thus, the generated powder layer exhibited higher heat absorption and dissipation rates. Therefore, a high solidification rate is facilitated, thereby suppressing microsegregation. The findings contribute to PBF knowledge related to feedstock, thus proving to be an essential reference for selecting and optimizing metallic powders applicable to additive manufacturing.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86452706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Alternative General Disciplines for Plastic Flow, New Phenomenological and Crystal-Plasticity Models Applicable from Quasi-Static to Extreme High Strain Rate Loadings 塑性流动的可选一般学科，适用于准静态到极高应变率载荷的新现象学和晶体塑性模型

AMI: Acta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3931607

Yinghua Li, Yan-Qin Gu, Lingcang Cai, Lin Zhang

{"title":"Alternative General Disciplines for Plastic Flow, New Phenomenological and Crystal-Plasticity Models Applicable from Quasi-Static to Extreme High Strain Rate Loadings","authors":"Yinghua Li, Yan-Qin Gu, Lingcang Cai, Lin Zhang","doi":"10.2139/ssrn.3931607","DOIUrl":"https://doi.org/10.2139/ssrn.3931607","url":null,"abstract":"Traditional plasticity theories, either time-dependent phenomenological plasticity or crystal plasticity, have been discovered to have some inconsistency problems under dynamic loadings. Such discrepancy is essentially arisen from the fundamental postulation that only internal states of the material determine the additive plastic strain rate tensor. However, in logical, except for internal states, the external loading conditions are also close-relevant factors. In this article, we modified the fundamental postulation, and proposed a set of general disciplines for the determination of material plastic flow, which is based on the view that the plastic flow is determined by both internal states and external loading conditions, and is satisfied with the principle of maximal increment of entropy. Then, we proposed a crystal plasticity model and a phenomenological model based on the new disciplines. A few shock experiments on single-crystal zirconium were conducted to validate the new disciplines and models, including two shots of poly-crystal OFHC copper impacting and one shot of high-energy laser ablation. It was demonstrated that our disciplines and models are well-matched and applicable even up to the strain rate at the order of 109s-1.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80044144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Combinatorial Development of Multicomponent Invar Alloys Via Rapid Alloy Prototyping 基于快速成形技术的多组分Invar合金组合开发

AMI: Acta Materialia Pub Date : 2021-01-01 DOI: 10.2139/ssrn.3920957

Z. Rao, H. Springer, D. Ponge, Zhiming Li

引用次数: 4

n-Type Doping of ε-Ga 2O 3n Epilayers by High-Temperature Tin Diffusion 高温锡扩散法制备ε- ga2o 3n薄膜的n型掺杂

AMI: Acta Materialia Pub Date : 2020-12-31 DOI: 10.2139/ssrn.3757760

A. Bosio, A. Parisini, A. Lamperti, C. Borelli, Laura Fornasini, M. Bosi, I. Cora, Z. Fogarassy, B. Pécz, Z. Zolnai, A. Németh, S. Vantaggio, R. Fornari

引用次数: 0

M 7C 3: The Story of a Misunderstood Carbide m7c3:一个被误解的碳化物的故事

AMI: Acta Materialia Pub Date : 2020-12-18 DOI: 10.2139/ssrn.3751558

E. Eshed, D. Choudhuri, Shmuel Osovski

{"title":"M 7C 3: The Story of a Misunderstood Carbide","authors":"E. Eshed, D. Choudhuri, Shmuel Osovski","doi":"10.2139/ssrn.3751558","DOIUrl":"https://doi.org/10.2139/ssrn.3751558","url":null,"abstract":"Since the discovery of the M7C3-type carbide in 1935, it has been the subject of many experimental and theoretical studies. Initially, the structure was thought of as being either trigonal or hexagonal, while later publications indicated that the structure was more likely to be orthorhombic. Even today, 8 decades after its discovery, many publications claim that M7C3 carbides are either hexagonal or orthorombic “beyond doubt”, while others, acknowledge the lack of agreement in the literature and try to resolve it using first principles calculations which rely on the atomic positions in the previously suggested structures. To date, no hard evidence was presented to support either claim in an indisputable manner. Using EBSD (electron backscattered diffraction), TEM (transmission electron microscopy) diffractions and high-resolution STEM (scanning transmission electron microscopy) imaging gathered from 8 zone-axis of the (Cr,Fe)7C3 phase formed in the as-cast AlCrFe2Ni2 high entropy alloy, we were able to determine that only the hexagonal structure is a viable option. Furthermore, we demonstrate the co-existence of two variants of the newly revealed atomic structure which we believe were mistakenly identified as stacking faults in previous studies.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"122 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87745470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Low-Cycle Fatigue Life and Plasticity Mechanisms of a Fe−15Mn−10Cr−8Ni−4Si Seismic Damping Alloy Under Cyclic Loading at Various Temperatures Fe - 15Mn - 10Cr - 8Ni - 4Si抗震阻尼合金在不同温度下的低周疲劳寿命及塑性机理

AMI: Acta Materialia Pub Date : 2020-12-18 DOI: 10.2139/ssrn.3746794

T. Sawaguchi, I. Nikulin, K. Ogawa, S. Takamori, Fumiyoshi Yoshinaka, Yuya Chiba, H. Otsuka, Yasuhiko Inoue, A. Kushibe

{"title":"Low-Cycle Fatigue Life and Plasticity Mechanisms of a Fe−15Mn−10Cr−8Ni−4Si Seismic Damping Alloy Under Cyclic Loading at Various Temperatures","authors":"T. Sawaguchi, I. Nikulin, K. Ogawa, S. Takamori, Fumiyoshi Yoshinaka, Yuya Chiba, H. Otsuka, Yasuhiko Inoue, A. Kushibe","doi":"10.2139/ssrn.3746794","DOIUrl":"https://doi.org/10.2139/ssrn.3746794","url":null,"abstract":"A recently developed Fe−15Mn−10Cr−8Ni−4Si (FMS) seismic damping alloy has a superior fatigue life at room temperature due to reversible dislocation motion associated with the γ → e martensitic transformation. The effect of temperature on the low-cycle fatigue life (N f) and the associated plasticity mechanisms of the FMS alloy were evaluated between 253 and 393 K. The longest (N f of 15,644 was obtained at 313 K. The (N f was dependent on the plasticity mechanisms, which were subdivided into three temperature regions with respect to the upper temperature limits for stress-assisted and strain-induced martensitic transformation (Msσ and Mdσ, respectively). At temperatures below Msσ, the Nf exceeded 5,000 cycles, where e-martensite was dominant and a long period stacking ordered structure was formed. The longest Nf values of over 10,000 cycles were obtained in the dual γ/e-phase formed between Mdσ and Mdσ, while Nf decreased rapidly as the deformation temperature increased beyond Mdσ. The effect of temperature on the N f of the FMS alloy was comparable to that of Fe–28Mn–6Si–5Cr shape memory alloy, and to the chemical composition dependence of N f of Fe–30Mn–(6 – x)Si–x Al (x= 0-6) transformation- and twinning-induced plasticity (TRIP/TWIP) steels. A new set of thermodynamic parameters was established to calculate the Gibbs free energy difference between the phases (ΔGγ→e) and the stacking fault energy of austenite (ΓSFE). The superior N f was associated with the cyclic strain-induced martensitic transformation when ΔGγ→e was between –50 and 100 Jmol-1, while reversible martensitic transformation relied on a ΔGγ→e of ~0 Jmol-1.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79979811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Disparity in Recrystallization of α- & γ-Fibers and its Impact on Cube Texture Formation in Non-Oriented Electrical Steel 无取向电工钢中α-和γ-纤维再结晶差异及其对立方织构形成的影响

AMI: Acta Materialia Pub Date : 2020-12-04 DOI: 10.2139/ssrn.3742922

D. Hawezy, S. Birosca

{"title":"Disparity in Recrystallization of α- & γ-Fibers and its Impact on Cube Texture Formation in Non-Oriented Electrical Steel","authors":"D. Hawezy, S. Birosca","doi":"10.2139/ssrn.3742922","DOIUrl":"https://doi.org/10.2139/ssrn.3742922","url":null,"abstract":"An investigation into the recovery and recrystallization of the two major texture fibres during annealing, namely α and γ, yielded subtle differences between the two. It is reported that with thermal activation static recovery occurs, where dislocation free sub-grains are formed and tend to grow, coalesce, or bulge out. This can form new strain-free recrystallisation nuclei, with the coalesce or bulging phenomenon depending on stored energy and geometrically dislocation density (GND). Due to low lattice curvature or otherwise, it was found α-fiber has low stored energy and GND values which favours bulging into neighbouring deformed grains as opposed to subgrain coalescement. In contrast, γ-fiber tends to undergo rapid subgrain coalescement due to high lattice curvature, i.e., GND and stored energy. The newly formed grains from both texture fibers were also found to typically differ in size, as γ-fiber has a much higher nucleation rate with rapid subgrain coalescence. Furthermore, it was discovered that Cube texture component though nucleating in higher rates within α-fiber, nucleates in all regions of high dislocation densities but will only survive in regions with a low recovery and nucleation rates, typically as in α-fiber state condition. Moreover, Goss texture component was found to preferentially nucleate from γ-fiber.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"19 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91421037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Formative and Controlled Mechanisms of Nano-Sized γ' Precipitates with Local Phase-Transition within Dislocation Networks of Nickel-Based Single Crystal Superalloys 镍基单晶高温合金位错网络中具有局部相变的纳米γ′相形成及控制机制

AMI: Acta Materialia Pub Date : 2020-11-20 DOI: 10.2139/ssrn.3734070

Wanshun Xia, Xinbao Zhao, Quanzhao Yue, L. Yue, Jiangwei Wang, Qingqing Ding, H. Bei, Ze Zhang

{"title":"Formative and Controlled Mechanisms of Nano-Sized γ' Precipitates with Local Phase-Transition within Dislocation Networks of Nickel-Based Single Crystal Superalloys","authors":"Wanshun Xia, Xinbao Zhao, Quanzhao Yue, L. Yue, Jiangwei Wang, Qingqing Ding, H. Bei, Ze Zhang","doi":"10.2139/ssrn.3734070","DOIUrl":"https://doi.org/10.2139/ssrn.3734070","url":null,"abstract":"The local region of dislocation networks in a nickel-based single crystal superalloy crept under 1373K and 137MPa is spatially divided to two parts: gridlines which compose the arrangements of dislocation networks and mesh regions as intervals between gridlines. The formative and controlled mechanisms of nano-sized γ′ precipitates (γ′ n ) in mesh region are revealed. The enhanced segregation of Cr, Co and Re along gridlines with transformation of dislocation networks from transitional to equilibrium arrangements left the higher contents of γ′-rich elements such as Al in mesh region that facilitates the local phase transition and precipitation of γ′ n . However, the growth of γ′ n precipitates in mesh region, which requires great amounts of solutes diffusion of γ′-rich elements, is restricted by chemical barrier formed along gridlines of dislocation networks. Complete coherent interfaces between ordering mesh region and disordered gridlines could form γ/γ′ substructures to stabilize dislocation networks. In dendrite core, higher contents of Re, W and Mo effectively increase the lattice misfit to form denser dislocation networks. It can expect further subdivided γ/γ′ substructures in dendrite core increase the creep resistance to retard degradation of dislocation networks and topological inversion of rafted structures.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75891027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

On the Brittle-to-Ductile Transition of the As-Cast TiVNbTa Refractory High-Entropy Alloy 铸态TiVNbTa难熔高熵合金脆性向韧性转变的研究

AMI: Acta Materialia Pub Date : 2020-10-22 DOI: 10.2139/ssrn.3708719

R. Scales, David J Armstrong, A. Wilkinson, Bobo Li

引用次数: 10