Download or read book Directional Solidification Microstructures and Mechanical Properties of Cr Cr3Si Eutectic Alloys written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Alloys based on intermetallics have been considered for high temperature structural applications. However, many of these alloys suffer from intrinsic brittleness and low fracture toughness at ambient temperature. Therefore, ductile-phase-toughened intermetallic composites are being investigated as a means to improve the fracture toughness. A subset of this class of materials is in-situ composites produced by directional solidification of intermetallic eutectics. In this study, the Cr-Cr3Si eutectic system is selected as a model system to investigate composites by directional solidification, where the strong, but brittle Cr3Si is combined with a more ductile Cr-rich solid solution. A series of binary Cr-Si alloys with silicon concentrations ranging from 13 to 24 at.% were produced by arc melting and drop casting. These compositions span the composition (15 at.% Si) at which a eutectic reaction is reported in the phase diagram. The microstructure of the Cr-16.05 at.% Si alloy is fully lamellar and devoid of any proeutectic phases suggesting that the best composition for obtaining a fully lamellar structure is Cr-16.05 at.% Si rather than the eutectic composition (Cr-15 at.% Si) indicated in the phase diagram. The eutectic microstructure consists of alternating lamellae of Cr (solid solution) and Cr3Si (intermetallic). Uniform and well-aligned lamellar structures were obtained over a fairly wide range of solidification conditions, but not at very low or very high growth rates where degenerate and cellular structures, respectively, were obtained. The lamellar spacing was found to increase with decreasing solidification rate, in agreement with the Jackson-Hunt theory. In addition, for a fixed growth rate, the lamellar spacing was found to increase with increasing rotation rate. The growth directions in the lamellar eutectic were found to be 100 for the Cr3Si phase and 111 for the Cr solid solution phase. Eutectic microstructures (rod or lamellar) could also be produced at off-eutectic compositions, but only for a limited range of growth conditions. The mechanical properties of the individual lamellae and the Cr-Cr3Si composites were examined by nanoindentation, Vicker's hardness testing and three-point bend testing. It was found that the Vicker's hardness of Cr-Cr3Si composites is about HV847, independent of the lamellar spacing. The Young's modulus of the Cr-Cr3Si eutectic composites measured by ultrasonic techniques is 312 GPa, which is in reasonably good agreement with the nanoindentation results (within 5%). The fracture toughness of single crystals of Cr3Si is very low (2.6 MPa[square root]m).
Download or read book Eutectic Solidification Processing written by Roy Elliott and published by Elsevier. This book was released on 2013-10-22 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: Eutectic Solidification Processing: Crystalline and Glassy Alloys deals with solidification theory and its application to eutectic processing of crystalline and glassy alloys. The underlying theme is an analysis of the different paths taken by the liquid-solid transformation as the cooling rate increases and a description of the structure and properties of the solid formed, ranging from equilibrium to metastable phase formation in castings, to metallic glass formation in splat quenched ribbons. This text has seven chapters; the first of which describes the main characteristics of the liquid-solid transformation. The chapters that follow show how control over composition, trace impurities, heat flow and cooling rate, and nucleation and growth gives rise to a wide range of solidification structures. Models of the nucleation and growth of eutectic and primary phases are analyzed and used to explain how cast microstructures are formed. Aluminum casting alloys and all types of cast iron are discussed, along with primary phase formation, the dependence of the extent of segregation on solidification conditions, and the practice of segregation prevention during solidification. This book also describes the importance of fluid flow in producing macroscopic segregation in large ingots and considers ways of minimizing this defect. Finally, this book gives a brief account of the various types of metallic glasses, their fabrication, important properties, and potential applications. This book will be of interest to materials scientists and industrial materials engineers.
Download or read book Solidification Microstructure and Mechanical Properties of Rapidly Solidified Eutectic Alloys written by and published by . This book was released on 1979 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solidification Microstructure and Mechanical Properties Or Rapidly Solidified Eutectic Alloys written by F. S. J. Jabczynski and published by . This book was released on 1979 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Properties of Directionally Solidified Al Si Eutectic written by and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of directional solidification on the yield strength of the Al-Si eutectic alloy has been studied. Eutectic alloys (Al-12.7 wt. % Si) were directionally frozen at growth rates, R, between 0.097 cm/h and 47.0 cm/h through a temperature gradient of about 80°C/cm. As found by Day and Hellawell, an oriented (001) Si fiber texture is obtained for rates less than 1.0 cm/hr, and at higher growth rates microstructures similar to the as-cast eutectic are found. At the lower growth rates, banded structures alternating rich in Si and lean in Si were also observed. Tensile measurements indicated that the yield strength is independent of R at growth rates less than ca. 1.0 cm/h, while at higher growth rates the strength increases linearly with R14. Composite strengthening due to aligned Si microstructure at low R was not exhibited due to the preferential yielding within the banded structures. Yield strengths for higher growth rates are controlled by a precipitate spacing effect.
Download or read book Microstructure and Properties of Materials written by James Chen-Min Li and published by World Scientific. This book was released on 1996 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the second volume of an advanced textbook on microstructure and properties of materials. (The first volume is on aluminum alloys, nickel-based superalloys, metal matrix composites, polymer matrix composites, ceramics matrix composites, inorganic glasses, superconducting materials and magnetic materials). It covers titanium alloys, titanium aluminides, iron aluminides, iron and steels, iron-based bulk amorphous alloys and nanocrystalline materials.There are many elementary materials science textbooks, but one can find very few advanced texts suitable for graduate school courses. The contributors to this volume are experts in the subject, and hence, together with the first volume, it is a good text for graduate microstructure courses. It is a rich source of design ideas and applications, and will provide a good understanding of how microstructure affects the properties of materials.Chapter 1, on titanium alloys, covers production, thermomechanical processing, microstructure, mechanical properties and applications. Chapter 2, on titanium aluminides, discusses phase stability, bulk and defect properties, deformation mechanisms of single phase materials and polysynthetically twinned crystals, and interfacial structures and energies between phases of different compositions. Chapter 3, on iron aluminides, reviews the physical and mechanical metallurgy of Fe3Al and FeAl, the two important structural intermetallics. Chapter 4, on iron and steels, presents methodology, microstructure at various levels, strength, ductility and strengthening, toughness and toughening, environmental cracking and design against fracture for many different kinds of steels. Chapter 5, on bulk amorphous alloys, covers the critical cooling rate and the effect of composition on glass formation and the accompanying mechanical and magnetic properties of the glasses. Chapter 6, on nanocrystalline materials, describes the preparation from vapor, liquid and solid states, microstructure including grain boundaries and their junctions, stability with respect to grain growth, particulate consolidation while maintaining the nanoscale microstructure, physical, chemical, mechanical, electric, magnetic and optical properties and applications in cutting tools, superplasticity, coatings, transformers, magnetic recordings, catalysis and hydrogen storage.
Download or read book Micromechanical study on the deformation behaviour of directionally solidified NiAl Cr eutectic composites written by Kumar, Amritesh and published by KIT Scientific Publishing. This book was released on 2017-11-06 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Defect Properties and Related Phenomena in Intermetallic Alloys Volume 753 written by Materials Research Society. Meeting and published by . This book was released on 2003-06-25 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Defects such as dislocations, antiphase domains and grain boundaries, interstitials/substitutionals, and vacancies affect many physical and mechanical properties of ordered intermetallics. As a result, they often play a decisive role in determining the macroscopic behavior of not just structural intermetallics but also 'functional' intermetallics such as shape memory alloys and hydrogen storage materials. This book follows in the general tradition of the highly successful series of MRS symposia titled High-Temperature Ordered Intermetallic Alloys. However, it also represents a significant departure from its predecessors: it includes papers on functional intermetallics in addition to papers on structural intermetallics; and focuses on defects and how they affect various properties of interest in structural and functional intermetallics. Roughly 30 percent of the papers in the book are on functional intermetallics, including materials for hydrogen storage, magnetic, and shape memory applications. The remaining papers deal with structural intermetallics, including the still active areas of nickel-, iron-, and titanium-aluminides, as well as the newer materials for ultrahigh-temperature applications.
Download or read book Thermal Stability of Binary Cr Cr3Si and Ternary NiAl Mo Eutectic Alloys written by Aravind Gali and published by . This book was released on 2006 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thermal stability of multiphase intermetallics at temperatures to 1400°C was investigated by studying two model eutectic systems: Cr-Cr3Si having a lamellar microstructure and NiAl-Mo having a fibrous microstructure. In drop cast Cr-Cr3Si, coarsening was found to be interface controlled. The coarsening rate could be significantly reduced by microalloying with Ce and Re, two elements which were chosen because they were expected to segregate to the Cr-Cr3Si interfaces and decrease their energies. Similarly, directional solidification, which is also expected to lower the Cr-Cr3Si interfacial energy, was found to dramatically decrease the coarsening rate. In the case of NiAl-Mo, coarsening was found to occur by fault migration and annihilation. Microalloying with B was found to significantly decrease the coarsening rate. The fiber density in the B-doped alloy was smaller than in the undoped alloy, suggesting that B affects the coarsening rate by lowering the fault density. X-ray energy dispersive spectroscopy (XEDS) analysis of Ce doped drop cast Cr-Cr3Si showed that Ce is present at the Cr/Cr3Si interface. XEDS analysis of Re doped Cr-Cr3Si and EELS analysis of B doped NiAl-Mo were inconclusive.
Download or read book Advanced Intermetallic based Alloys written by Jörg Wiezorek and published by . This book was released on 2007 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of Fatigue and Fracture Behavior of Cr Based Alloys and Intermetallic Materials written by and published by . This book was released on 2001 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The microhardness, and tensile and fracture-toughness properties of drop-cast and directionally-solidified Cr-9.25 at.% (atomic percent) Ta alloys have been investigated. Directional solidification was found to soften the alloy, which could be related to the development of equilibrium and aligned microstructures. It was observed that the tensile properties of the Cr-Ta alloys at room and elevated temperatures could be improved by obtaining aligned microstructures. The directionally-solidified alloy also showed increased fracture toughness at room temperature. This trend is mainly associated with crack deflection and the formation of shear ribs in the samples with aligned microstructures. The sample with better-aligned lamellar exhibits greater fracture toughness.
Download or read book Solidification Processing of Eutectic Alloys written by D. M. Stefanescu and published by . This book was released on 1988 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of a symposium held during the Society's Fall meeting in Cincinnati, Ohio, October 1988. The 15-article collection addresses growth analysis, experiments with directional solidification, advanced casting methods. Emphasis is on cast iron, aluminum-base alloys, melt innoculation, and othe
Download or read book Abstracts written by Materials Research Society. Meeting and published by . This book was released on 1992 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solidification Processes and Microstructures written by Michel Rappaz and published by Wiley-TMS. This book was released on 2004-03 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Papers from a March 2004 symposium describe recent work in solidification processes and microstructures in the areas of mushy zone dynamics, rapid solidification, and phase field modeling. Some specific topics include kinetics of dendritic mushy zones, anisotropy effects in lamellar eutectic growth, network modeling of liquid metal transport in solidifying aluminum alloys, and the topology of coarsened microstructures. Other topics include diffuse solid-liquid interfaces and solute trapping, phase selection transitions during undercooled melt solidification, dendritic growth in confined spaces, the influence of foreign particles in the formation of polycrystalline solidification patterns, and a cellular automaton for growth of solutal dendrites. Annotation : 2004 Book News, Inc., Portland, OR (booknews.com).
Download or read book Semi Solid Processing of Alloys and Composites XIII written by Michael Modigell and published by Trans Tech Publications Ltd. This book was released on 2014-09-19 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt: Collection of selected, peer reviewed papers from the 13th International Conference on Semi-Solid Processing of Alloys and Composites (S2P 2014), September 15-17, 2014, Muscat, Sultanate of Oman. The 68 papers are grouped as follows: Chapter 1: Material Development and Characterisation, Chapter 2: Rheology, Modelling and Simulation, Chapter 3: Process Development, Chapter 4: Industrial Application
Download or read book An Investigation of the Microstructure and Mechanical Properties of Thick Section CR MO Steels written by Rameshchandra Jitendrakumar Kar and published by . This book was released on 1979 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
