AMI: Acta Materialia最新文献_第9页

Non-Synchronized Rotation of Layered Spin Configurations in La 0.825Sr 0.175MnO 3/SrTiO 3 Film La 0.825Sr 0.175 mno3 / srtio3薄膜层状自旋构型的非同步旋转

AMI: Acta Materialia Pub Date : 2019-04-11 DOI: 10.2139/ssrn.3370282

Xin Li, Jingzhi Han, Xiongzuo Zhang, R. Wu, Yinfeng Zhang, Haidong Tian, M. Xue, X. Wen, Zhichao Li, Shunquan Liu, Wenyun Yang, Changsheng Wang, H. Du, Xiaodong Zhang, Yingchang Yang, Jinbo Yang

{"title":"Non-Synchronized Rotation of Layered Spin Configurations in La 0.825Sr 0.175MnO 3/SrTiO 3 Film","authors":"Xin Li, Jingzhi Han, Xiongzuo Zhang, R. Wu, Yinfeng Zhang, Haidong Tian, M. Xue, X. Wen, Zhichao Li, Shunquan Liu, Wenyun Yang, Changsheng Wang, H. Du, Xiaodong Zhang, Yingchang Yang, Jinbo Yang","doi":"10.2139/ssrn.3370282","DOIUrl":"https://doi.org/10.2139/ssrn.3370282","url":null,"abstract":"Magnetic properties of single perovskite-structure epitaxial film are reported to have layered distribution recently. However, the different responses of spin configurations in individual layers to the variation of temperature and strain state, especially the subtle response of layered film due to structural phase transformation of SrTiO3 (STO) substrate around 105 K, have not been revealed completely. Drastic drop and concomitant abnormal increase of remnant magnetic moments (REM) and coercivity of low-doped La1-xSrxMnO3 (x=0.175) /SrTiO3 film were observed for the first time around 105 K only in the in-plane direction, and layered magnetic structures were further inferred based on investigation of microstructure, strain distribution and chemical inhomogeneity. Abnormal change of magnetic properties around 105 K was discussed by a three-layer model, in which softer ferromagnetic layer was supposed to form in the middle layer of strain induced layered structure, and the spin configuration of middle layer underwent non-synchronous transformation relative to other parts of the film, which may be attributed to the change of in-plane strain inside the film around 105 K. Our work reveals the variation of individual magnetic layers with the increase of temperature through utilizing the remnant magnetic field in measuring system, and the abrupt reversal of spin configuration at the intermediate layer can also serve the design of novel spintronics devices in the future.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85347851","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

A New Approach to Predict the Strength Criterion of Frozen Soils Based on Micromechanical Framework 基于细观力学框架的冻土强度准则预测新方法

AMI: Acta Materialia Pub Date : 2019-01-10 DOI: 10.2139/ssrn.3313263

De Zhang, E. Liu

{"title":"A New Approach to Predict the Strength Criterion of Frozen Soils Based on Micromechanical Framework","authors":"De Zhang, E. Liu","doi":"10.2139/ssrn.3313263","DOIUrl":"https://doi.org/10.2139/ssrn.3313263","url":null,"abstract":"In the present study, a micromechanics-based strength criterion for frozen soils is proposed to estimate the macroscopic nonlinear strength properties of the matrix-inclusion systems. In the representative frozen soil element, the strength behaviors of soil particles and ice-crystals are assumed to be respectively characterized by two different elliptical strength criteria. With consideration of Mori-Tanaka scheme in continuum micromechanics, the interactions between soil particles and ice-crystals could well be taken into account by means of homogenization techniques, and moreover the φ-breakage function is introduced to describe the cracked effect of ice-crystals regardless of the influence of unfrozen water. In the framework of support function and plastic dissipative energy, the strength criterion is formulated with the equivalent principle from the microscopic and macroscopic viewpoint. The parameters of ice-crystals are decided in the reported literature with different temperatures, and meanwhile those of soil particles are determined by various soil types such as silty soils, loess and sands. In addition, the parameters in the proposed strength criterion have clear physical meanings by comparisons with macroscopic strength criterion. Compared with the existing experimental data, the predictions in the proposed strength criterion can qualitatively and quantitatively simulate the macroscopic strength responses of frozen soils.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86044272","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

Atomistic Insights into Hydration Reactivity of Clinker Crystals with Chemical Impurity 熟料晶体与化学杂质水化反应性的原子观察

AMI: Acta Materialia Pub Date : 2019-01-10 DOI: 10.2139/ssrn.3313265

Yong Tao, Wenqin Zhang, Neng Lia, W. Ching, Fazhou Wang, Shu-guang Hu

引用次数: 0

Modeling Grain Boundary Segregation by Prediction of All Necessary Parameters 通过预测所有必要参数来模拟晶界偏析

AMI: Acta Materialia Pub Date : 2019-01-04 DOI: 10.2139/ssrn.3310277

P. Lejček, S. Hofmann

引用次数: 0

DFT+ U Study of the Thermal Conductivity and Noble Gas Impurities in Uranium Dioxide 二氧化铀热导率及惰性气体杂质的DFT+ U研究

AMI: Acta Materialia Pub Date : 2019-01-04 DOI: 10.2139/ssrn.3310275

E. Torres, T. Kaloni

引用次数: 0

Control of Nanoscale Precipitation and Elimination of Intermediate-Temperature Embrittlement in Multicomponent High-Entropy Alloys 多组分高熵合金中纳米级析出控制与中温脆化消除

AMI: Acta Materialia Pub Date : 2019-01-01 DOI: 10.2139/ssrn.3477998

Tao Yang, PhD, Yilu Zhao, PhD, Lei Fan, PhD, Jie Wei, PhD, Junhua Luan, PhD, Weihong Liu, PhD, Cheng Wang, PhD, Zengbao Jiao, PhD, Ji-jung Kai, PhD, C.T. Liu, Phd

{"title":"Control of Nanoscale Precipitation and Elimination of Intermediate-Temperature Embrittlement in Multicomponent High-Entropy Alloys","authors":"Tao Yang, PhD, Yilu Zhao, PhD, Lei Fan, PhD, Jie Wei, PhD, Junhua Luan, PhD, Weihong Liu, PhD, Cheng Wang, PhD, Zengbao Jiao, PhD, Ji-jung Kai, PhD, C.T. Liu, Phd","doi":"10.2139/ssrn.3477998","DOIUrl":"https://doi.org/10.2139/ssrn.3477998","url":null,"abstract":"Thermally stable high-entropy alloys (HEAs) consisting of a high density of coherent precipitates show a great potential for high-temperature applications. In this work, we systematically investigated the phase stability and coarsening kinetics of L12-type coherent precipitates in a Ni-Co-Fe-Cr-Al-Ti-based HEA isothermally aged at 800, 900 and 1000 °C. Aged microstructures in the grain interiors under this temperature range were essentially dominated by the uniform precipitation of multicomponent L12 (Ni, Co, Fe, Cr)3(Ti, Al)-type precipitates. The coarsening kinetics of these intragranular L12 precipitates were quantitatively determined, which were adequately characterized by the classical Lifshitz-Slyozov-Wagner model. The activation energy for coarsening was determined to be 378 kJ/mol, which is relatively higher than that of conventional Ni or Co-based superalloys, suggesting a slow elemental diffusion in the HEA matrix. More importantly, the heterogeneous precipitation and the associated metastable phase transformation mechanism along grain boundaries (GBs) were carefully analyzed. Localized chemical heterogeneity was identified within the discontinuous L12 phase at the GBs, which thermodynamically destabilizes the L12 structure and encourages the formation of brittle Heusler phase. Finally, we establish a unique duplex-aging strategy that can be efficiently utilized for GB stabilization, by which these detrimental intergranular heterostructures can be greatly eliminated, leading to an exceptional resistance to intermediate-temperature embrittlement, along with enhanced tensile strengths. These findings will not only shed light on the precipitation mechanisms in compositionally complex HEAs but also generate new opportunities to the interfacial design of HEAs for advanced high-temperature applications with superior properties.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90856429","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

Application of Laboratory Based Laue Micro-XRD for Generalised Grain Orientation Mapping 基于实验室的lae微xrd在广义晶粒取向制图中的应用

AMI: Acta Materialia Pub Date : 2019-01-01 DOI: 10.2139/ssrn.3446901

P. Lynch, W. Stevenson, D. Fox, A. Ghaderi, L. Xie, M. R. Barnett

{"title":"Application of Laboratory Based Laue Micro-XRD for Generalised Grain Orientation Mapping","authors":"P. Lynch, W. Stevenson, D. Fox, A. Ghaderi, L. Xie, M. R. Barnett","doi":"10.2139/ssrn.3446901","DOIUrl":"https://doi.org/10.2139/ssrn.3446901","url":null,"abstract":"A fully automated laboratory Micro X-ray Laue diffraction system capable of illuminating individual grains in polycrystalline sample is described. A high brightness tungsten micro-focus X-ray source coupled with a capillary focussing optic is used to define a variable spot, ranging in size from 20micron to 200 micron, on the sample. Extension of the Laue technique for micro-texture mapping is then achieved by raster scanning the sample in the focal plane of the focussing optic. The attributes of this new methodology is highlighted by a series of 3 case studies. The first case study demonstrates the high-angular resolution capabilities based on orientation mapping in large grain Si steel electrical transformer plates. An angular resolution better than 0.01degree was readily achieved. Further, the orientation and grain morphology was verified based on synchrotron Laue maps acquired from the same region of interest. Case study 2 addresses the minimum grain size/resolution that can be practically measured. By use of the 20micron probe size orientation maps were acquired for an additive manufactured Ti-5553 wall. A bimodal grain size could be identified. These results were in good agreement with EBSD measurements performed on a sample prepared under the same conditions. Finally, demonstration of large scale grain orientation mapping was performed on an as-received Ti-5553 billet. An orientation map of 65 x 35mm at a step resolution of 0.2mm was used to map the orientation and change in grain morphology across the billet.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89921704","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

The Effect of Grain Boundary Structure on the Intergranular Degradation Behavior of Solution Annealed Alloy 690 in Simulated Pressurized Water Reactor Primary Environment 晶界组织对690固溶退火合金在模拟压水堆初始环境中晶间降解行为的影响

AMI: Acta Materialia Pub Date : 2019-01-01 DOI: 10.2139/ssrn.3427530

Wenjun Kuang, G. Was

{"title":"The Effect of Grain Boundary Structure on the Intergranular Degradation Behavior of Solution Annealed Alloy 690 in Simulated Pressurized Water Reactor Primary Environment","authors":"Wenjun Kuang, G. Was","doi":"10.2139/ssrn.3427530","DOIUrl":"https://doi.org/10.2139/ssrn.3427530","url":null,"abstract":"The environmental degradation of four different types of grain boundaries were investigated on alloy 690 following slow strain rate tensile tests in 360 oC hydrogenated water. Random high angle boundaries (RHABs) support fast Cr diffusion that promotes the formation of a compact surface oxide film and grain boundary migration. Surprisingly, coherent twin boundaries (CTBs) are susceptible to intergranular oxidation and do not exhibit Cr diffusion or grain boundary migration. When CTBs are changed to transformed twin boundaries (TTBs) by cold work, they behave like RHABs. Finally, incoherent twin boundaries (ITBs) undergo intergranular oxidation with limited Cr depletion but no boundary migration beyond the oxide. The Cr diffusivity along grain boundary in this alloy is directly related to the density of coincident site in the grain boundary plane and determines the morphology of oxide formed near the grain boundary. CTBs are still highly resistant to stress corrosion cracking (SCC) due to the semi-coherent interface between the intergranular chromia and grain matrix. In contrast, the intergranular oxides formed along RHABs inherit highly-disordered boundary structure from the original grain boundaries and show much higher SCC susceptibility. The grain boundary structure dependence of SCC resistance should be understood from its effects on solute diffusivity, structure of intergranular oxide and the local stress-strain state.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"85 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77320945","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

Antiphase Boundaries, Magnetic Domains, and Magnetic Vortices in Ni-Mn-Ga Single Crystals Ni-Mn-Ga单晶的反相边界、磁畴和磁涡

AMI: Acta Materialia Pub Date : 2019-01-01 DOI: 10.2139/ssrn.3465853

M. Vronka, L. Straka, M. Graef, O. Heczko

{"title":"Antiphase Boundaries, Magnetic Domains, and Magnetic Vortices in Ni-Mn-Ga Single Crystals","authors":"M. Vronka, L. Straka, M. Graef, O. Heczko","doi":"10.2139/ssrn.3465853","DOIUrl":"https://doi.org/10.2139/ssrn.3465853","url":null,"abstract":"The interplay between antiphase boundaries (APBs), magnetic domain structure and functional properties was investigated in the martensitic state of Ni-Mn-Ga single crystals which showed magnetically induced martensite reorientation (MIR) with 6% strain. The APB density was controlled by different heat treatments and the APBs and magnetic domains were observed by Lorentz transmission electron microscopy (LTEM). Slow cooling at ~1 K/min resulted in a low density (<1/μm), air quenching in a medium density (≈8/μm), and water quenching in a high density (≈15/μm) of APBs. Abundant pinning of domain walls on APBs was observed, which resulted in one-to-one correspondence between the magnetic domain walls and antiphase boundaries (APBs), magnetic domain memory, and finer domain patterns for the high APB density. For low APB density, a labyrinth domain structure was established between domain walls pinned on APBs. For low and medium density of APBs the magnetization was oriented mostly parallel to the out-of-plane easy magnetization axis. For high APB density the magnetization switched to the in-plane orientation, indicating that the effective magnetic anisotropy became lower than the stray field energy, and magnetic vortices additionally appeared. The novel functionalities based on a combination of MIR and interactions of the magnetic structure with APBs are feasible since the MIR was observed even for the highest density of APBs.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85198389","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

Ice-Templated Porous Tungsten and Tungsten Carbide 冰模板多孔钨和碳化钨

AMI: Acta Materialia Pub Date : 2019-01-01 DOI: 10.2139/ssrn.3427539

Y. Zhang, Guoqi Tan, D. Jiao, Jian Zhang, Shaogang Wang, Feng Liu, Zengqian Liu, L. Zhuo, Zhefeng Zhang, S. Deville, R. Ritchie

{"title":"Ice-Templated Porous Tungsten and Tungsten Carbide","authors":"Y. Zhang, Guoqi Tan, D. Jiao, Jian Zhang, Shaogang Wang, Feng Liu, Zengqian Liu, L. Zhuo, Zhefeng Zhang, S. Deville, R. Ritchie","doi":"10.2139/ssrn.3427539","DOIUrl":"https://doi.org/10.2139/ssrn.3427539","url":null,"abstract":"The structures of tungsten and tungsten carbide scaffolds play a key role in determining the properties of their infiltrated composites for multifunctional applications. However, the architectural construction of W/WC systems is challenging because of the difficulty of assembly due to their large densities. Here we present the generation of unidirectionally porous architectures, with high porosities exceeding 65%, for W and WC scaffolds using direct ice-templating techniques, which in many respects reproduce the design motif of wood. This was achieved by adjusting the viscosities of suspensions to retard sedimentation during freezing. The processing, structural characteristics and mechanical properties of the resulting scaffolds were investigated and the correlations between them explored. Quantitative relationships were established to describe their strengths based on a simple model taking into account both inter- and intra-lamellar pores. The fracture mechanisms were also identified, especially in light of the porosity. This study extends the effectiveness of ice-templating techniques for systems with large densities or particle sizes. It further provides preforms for developing new nature-inspired multifunctional materials, as represented by W/WC-Cu composites.","PeriodicalId":7755,"journal":{"name":"AMI: Acta Materialia","volume":"373 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76620436","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