ChemRN: Metals & Alloys (Topic)最新文献_第5页

Improvement of Grain Boundary Tolerance by Minor Additions of Hf and B in a Second Generation Single Crystal Superalloy 少量添加Hf和B改善第二代单晶高温合金的晶界公差

ChemRN: Metals & Alloys (Topic) Pub Date : 2018-11-23 DOI: 10.2139/ssrn.3289656

Y. Zhao, J. Zhang, Y. Luo, B. Zhang, G. Sha, Longfei Li, D. Tang, Q. Feng

{"title":"Improvement of Grain Boundary Tolerance by Minor Additions of Hf and B in a Second Generation Single Crystal Superalloy","authors":"Y. Zhao, J. Zhang, Y. Luo, B. Zhang, G. Sha, Longfei Li, D. Tang, Q. Feng","doi":"10.2139/ssrn.3289656","DOIUrl":"https://doi.org/10.2139/ssrn.3289656","url":null,"abstract":"Abstract Nowadays, it is challenging to completely eliminate low angle or high angle grain boundaries (LAGBs or HAGBs) from Nickel-based single crystal (SX) superalloys manufactured using the conventional directional solidification technique. The additions of C, B and Hf have been found to be an effective measure in improving the damage resistance of grain boundary (GB) defects, and thus increasing the creep resistance. However, the strengthening mechanism through their additions is still unclear. In this study, a double-seed solidification technique with two misorientation levels, i.e., 5° and 20°, was used to produce a series of bicrystal superalloys with different contents of Hf and B. It is the first report of an alloy with joint Hf and B addition that demonstrates tolerance to GBs with a misorientation as high as ∼20° under all of the creep conditions: 1100 °C/130 MPa, 980 °C/250 MPa and 760 °C/785 MPa. Interestingly, the effect of individual additions of Hf or B was not as pronounced as that of the joint Hf and B addition. To understand the influence of these additions on the creep mechanism in nickel-based superalloys with GB defects, a detailed characterization of the microstructures in the vicinity of the LAGBs or HAGBs was carried out, and the elemental distribution at the HAGBs was analyzed with various techniques. This study will be beneficial for understanding the role of Hf and B additions on improving the GB tolerance, and optimizing the Hf and B additions in nickel-based single crystal superalloys.","PeriodicalId":159806,"journal":{"name":"ChemRN: Metals & Alloys (Topic)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121246994","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: 36

Strong Shear-Flow Modulation of Instabilities in Rapid Directional Solidification 快速定向凝固不稳定性的强剪切流调制

ChemRN: Metals & Alloys (Topic) Pub Date : 2018-10-30 DOI: 10.2139/ssrn.3275440

K. Kowal, S. H. Davis

{"title":"Strong Shear-Flow Modulation of Instabilities in Rapid Directional Solidification","authors":"K. Kowal, S. H. Davis","doi":"10.2139/ssrn.3275440","DOIUrl":"https://doi.org/10.2139/ssrn.3275440","url":null,"abstract":"Abstract We examine the effect of a strong shear flow on morphological instabilities that occur in the directional solidification of a dilute, binary alloy when the interface departs from local thermal equilibrium in a frozen-temperature, one-sided model. In particular, the flow velocity U ∞ is much larger than the rate of solidification V and the Schmidt number is arbitrary. In contrast to solidification processes under small or no flow, for which both a cellular and an oscillatory mode of instability appear, the liquid-solid interface under flows of large magnitude is susceptible to a single mode of instability. All experiments on banding occur in the overlap region between these modes under no flow and since these two primary modes coalesce into one time-dependent, spatially-dependent mode, there is no mechanism for the production of bands anymore in the large-flow regime. No experiments have been conducted to date on this rapid solidification under flow and this suggests that such experiments would show no bands. The flow significantly stabilizes and selects higher wavenumbers for the preferred form of instability in comparison to systems involving small or no flow. The introduction of a strong flow provides an effective mechanism to eliminate instabilities at high solidification rates. However, stability thresholds at low solidification rates remain mainly indifferent to the presence of flow.","PeriodicalId":159806,"journal":{"name":"ChemRN: Metals & Alloys (Topic)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127622673","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: 3

Designing and Fabrication of Fixture for Friction Stir Welding of Aluminium AA6061 Alloys AA6061铝合金搅拌摩擦焊夹具的设计与制造

ChemRN: Metals & Alloys (Topic) Pub Date : 2018-01-17 DOI: 10.2139/ssrn.3104229

Akshansh Mishra, A. Rose, S. M, A. Singh

引用次数: 4

Glassy Amorphous Metal Injection Molded Induced Morphological Defects 非晶玻璃金属注射成型诱导的形态缺陷

ChemRN: Metals & Alloys (Topic) Pub Date : 2016-12-27 DOI: 10.3844/AJASSP.2016.1476.1482

R. Aversa, Daniela Parcesepe, R. Petrescu, Guanying Chen, F. Petrescu, F. Tamburrino, A. Apicella

引用次数: 119

Quality Improvement of Aluminum Alloy (LM-6) Casting Using Taguchi Method 田口法提高铝合金(LM-6)铸件质量

ChemRN: Metals & Alloys (Topic) Pub Date : 1900-01-01 DOI: 10.2139/ssrn.1487542

Ravneet kakria, Chandandeep, P. Thareja

{"title":"Quality Improvement of Aluminum Alloy (LM-6) Casting Using Taguchi Method","authors":"Ravneet kakria, Chandandeep, P. Thareja","doi":"10.2139/ssrn.1487542","DOIUrl":"https://doi.org/10.2139/ssrn.1487542","url":null,"abstract":"There is no alternative to the intricacy; evidenced through sand casting as a production route, economical and poised for shorter runs. Quality of castings and parametric control thereof is more important than that of die casting. With increasing demand for high-quality castings at close tolerances, a need however was felt to study ways to get the optimal settings for main parameters to ensure better surface finish. The requirement in unison was hitherto attempted in case of LM-6 Aluminum alloys castings, developed through green sand casting route. Five main parameters namely Bentonite clay, AFS Grain Fineness Number, Moisture, Pouring temperature and Coal dust were duly identified. The effects of the selected process parameters on the surface finish and the subsequent optimal settings of the parameters were accomplished using Taguchi’s method. Using L8 (27) orthogonal arrays, experiments were conducted as per experimental plans given in this array. The results indicate that the selected parameters significantly affect the surface finish of LM-6 Aluminum alloys castings. The confirmatory experiments have also been carried out to verify the optimal settings of the parameters.","PeriodicalId":159806,"journal":{"name":"ChemRN: Metals & Alloys (Topic)","volume":"111 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124721712","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: 3

Phase Selection and Morphological Evolution for a Dilute Al-Mg-Si Alloy Under Sub-Rapid Solidification 亚快速凝固条件下稀Al-Mg-Si合金的相选择与形态演变

ChemRN: Metals & Alloys (Topic) Pub Date : 1900-01-01 DOI: 10.2139/ssrn.3447512

Zedong Liu, Cheng Wang, Hong-fei Ju, M. Zha, Zhi-Ping Guan, Zhizheng Yang, Jiawang Song, Huiyuan Wang

引用次数: 0

Investigation on the Hot Deformation Behaviors and Globularization Mechanisms of Lamellar Ti-6Al-4V Alloy within a Wide Range of Deformation Temperatures 宽变形温度下层状Ti-6Al-4V合金热变形行为及球化机制研究

ChemRN: Metals & Alloys (Topic) Pub Date : 1900-01-01 DOI: 10.2139/ssrn.3438562

Yan Chong, T. Bhattacharjee, R. Gholizadeh, J. Yi, N. Tsuji

{"title":"Investigation on the Hot Deformation Behaviors and Globularization Mechanisms of Lamellar Ti-6Al-4V Alloy within a Wide Range of Deformation Temperatures","authors":"Yan Chong, T. Bhattacharjee, R. Gholizadeh, J. Yi, N. Tsuji","doi":"10.2139/ssrn.3438562","DOIUrl":"https://doi.org/10.2139/ssrn.3438562","url":null,"abstract":"In this study, the hot deformation behavior and microstructural evolution of Ti-6Al-4V alloy having a lamellar initial microstructure were systematically investigated within a wide range of deformation temperatures (700~950°C). Flow softening was commonly observed in the true stress-strain curves and the amount of flow softening gradually decreased with increasing deformation temperature. Based on the microstructure characterization and quantitative analysis of the deformed microstructures, the deformation temperatures were roughly divided into two regions, namely region I (900~950°C) and region II (700~900°C). By a detailed transmission electron microscopy (TEM) analysis, different globularization mechanisms of α phase were found for the two regions. At relatively higher deformation temperatures (region I), α lamellae sub-division and grain growth was determined to be the main globularization mechanism. At relatively lower deformation temperatures (region II), on the other hand, dynamic recrystallization (DRX) of α lamellae was confirmed to be the dominant globularization mechanism. The DRX of α lamellae firstly occurred either along the colony boundaries or at the lamellae kinking areas, and then expanded to the interiors of α lamellae. In addition, nano-twinning also acted as a secondary globularization mechanism of α lamellae in region II. Finally, it was found that the presence of α lamellae enhanced the DRX of β phase, by providing a strain partitioning between soft β phase and hard α phase as well as reducing the size of β phase.","PeriodicalId":159806,"journal":{"name":"ChemRN: Metals & Alloys (Topic)","volume":"241 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133551224","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

Deformation of μm- and μm-Sized Fe2.4wt.%Si Single- and Bi-Crystals with a High Angle Grain Boundary at Room Temperature μm和μm尺寸Fe2.4wt的变形。室温下具有高角度晶界的Si单晶和双晶

ChemRN: Metals & Alloys (Topic) Pub Date : 1900-01-01 DOI: 10.2139/ssrn.3539243

M. Heller, J. Gibson, R. Pei, S. Korte-Kerzel

{"title":"Deformation of μm- and μm-Sized Fe2.4wt.%Si Single- and Bi-Crystals with a High Angle Grain Boundary at Room Temperature","authors":"M. Heller, J. Gibson, R. Pei, S. Korte-Kerzel","doi":"10.2139/ssrn.3539243","DOIUrl":"https://doi.org/10.2139/ssrn.3539243","url":null,"abstract":"Plasticity in body-centred cubic (BCC) metals, including dislocation interactions at grain boundaries, is much less understood than in face-centred cubic (FCC) metals. At low temperatures additional resistance to dislocation motion due to the Peierls barrier becomes important, which increases the complexity of plasticity. Iron-silicon steel is an interesting, model BCC material since the evolution of the dislocation structure in specifically-oriented grains and at particular grain boundaries have far-reaching effects not only on the deformation behaviour but also on the magnetic properties, which are important in its final application as electrical steel.In this study, two different orientations of micropillars (1, 2, 4 µm in diameter) and macropillars (2500 µm) and their corresponding bi-crystals are analysed after compression experiments with respect to the effect of size on strength and dislocation structures. Using different experimental methods, such as slip trace analysis, plane tilt analysis and cross-sectional EBSD, we show that direct slip transmission occurs, and different slip systems are active in the bi-crystals compared to their single-crystal counterparts. However, in spite of direct transmission and a very high transmission factor, dislocation pile-up at the grain boundary is also observed at early stages of deformation. Moreover, an effect of size scaling with the pillar size in single crystals and the grain size in bi-crystals is found, which is consistent with investigations elsewhere in FCC metals.","PeriodicalId":159806,"journal":{"name":"ChemRN: Metals & Alloys (Topic)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115885109","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

Morphological Characteristics of Al 3SC Particles and Crystallographic Orientation of Al 3Sc/Al Interface in Cast Al-Sc Alloy 铸造Al- sc合金中Al- 3SC颗粒的形态特征及Al- 3SC /Al界面的结晶取向

ChemRN: Metals & Alloys (Topic) Pub Date : 1900-01-01 DOI: 10.2139/ssrn.3694771

K. Yan, Zhongwei Chen, Yanni Zhao, C. Ren, Wenjie Lu

{"title":"Morphological Characteristics of Al 3SC Particles and Crystallographic Orientation of Al 3Sc/Al Interface in Cast Al-Sc Alloy","authors":"K. Yan, Zhongwei Chen, Yanni Zhao, C. Ren, Wenjie Lu","doi":"10.2139/ssrn.3694771","DOIUrl":"https://doi.org/10.2139/ssrn.3694771","url":null,"abstract":"As a new type of grain refiner, rare earth element Sc has a strong grain refining effect on the microstructure of cast aluminum alloys. During the solidification process, the precipitation of Al3Sc primary particles in the molten metal act as heterogeneous nucleation cores, promoting Al nucleation, and greatly increasing the nucleation rate. In this paper, single Al3Sc particle and multiple Al3Sc particles cluster are extracted by the focused ion beam, and the whole and internal structure of the particles are systematically studied using scanning electron microscope and high-resolution transmission electron microscope. The study found that under the influence of strong anisotropy, the primaryAl3Sc particles have different growth rates in different crystal planes, and finally form a special morphological feature -a cubic shape as a whole and a \"funnel-shaped\" structure in part. The (111) and (110) planes of Al3Sc particles form a coarse dendrite structure, and a large number of fine rod-shaped structures appear on the (100) plane, the Al matrix is interposed between the rod-shaped structures. At the interface between Al3Sc and Al matrix, two crystallographic orientation relationships were observed. At the same time, a special pseudomorphic solid layer was observed at the interface between Al and Al3Sc particles. In addition to individual Al3Sc particles, it was also found that some Al3Sc particles grow in a nucleus at the same time and have the symmetrical morphology of rotating twins.","PeriodicalId":159806,"journal":{"name":"ChemRN: Metals & Alloys (Topic)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127526789","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

Effects of Strain Rate on the Strain Induced Martensite Nucleation and Growth in 301LN Metastable Austenitic Steel 应变速率对301LN亚稳奥氏体钢应变诱导马氏体形核和生长的影响

ChemRN: Metals & Alloys (Topic) Pub Date : 1900-01-01 DOI: 10.2139/ssrn.3834118

L. Pun, G. C. Soares, M. Isakov, M. Hokka

{"title":"Effects of Strain Rate on the Strain Induced Martensite Nucleation and Growth in 301LN Metastable Austenitic Steel","authors":"L. Pun, G. C. Soares, M. Isakov, M. Hokka","doi":"10.2139/ssrn.3834118","DOIUrl":"https://doi.org/10.2139/ssrn.3834118","url":null,"abstract":"The effects of strain rate on the strain induced α’-martensite nucleation and growth were analysed in this work. Tension tests were performed at room temperature at strain rates of 2×10-4 s-1 and 0.5 s-1 using small polished specimens, which fit inside a scanning electron microscope. The specimens were deformed incrementally, and microstructural evolution was tracked carefully at the same location. This approach allows analysing not only the spatial but also the temporal evolution of the α’-martensite. Optical microscopy images and electron backscatter diffraction (EBSD) measurements were taken for each plastic deformation increment. The size and number of α’-martensite particles were evaluated from the EBSD images, whereas the local microlevel plastic strains were obtained with Digital Image Correlation (DIC). According to the results, the number of nucleation sites for α’-martensite does not seem to be affected much by the strain rate. However, there is a notable strain rate effect on how the transformation proceeds in the neighbourhood of freshly formed α’-martensite particles. At low strain rate, repeated nucleation and coalescence leads to notable growth of the α’-martensite particles, whereas at high strain rate, once nucleated α’-martensite particles remain as small isolated islands which do not markedly grow with further plastic strain. This phenomenon can be attributed to local microstructure level heating caused by plastic deformation and the exothermic phase transformation. This reduces the local growth rate of the α’-martensite particles in the vicinity of the above-mentioned islands, thus leading to a lower bulk transformation rate at higher strain rates.","PeriodicalId":159806,"journal":{"name":"ChemRN: Metals & Alloys (Topic)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126643707","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