Interfacially-controlled Deformation Mechanisms in a Two-phase Alloy PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Interfacially-controlled Deformation Mechanisms in a Two-phase Alloy PDF full book. Access full book title Interfacially-controlled Deformation Mechanisms in a Two-phase Alloy by Hugh Bernard McLean. Download full books in PDF and EPUB format.
Author: Hugh Bernard McLean
Publisher:
ISBN:
Category :
Languages : en
Pages : 158
Get Book Here
Book Description
Author: Hugh Bernard McLean
Publisher:
ISBN:
Category :
Languages : en
Pages : 158
Get Book Here
Book Description
Author: Brian Joseph Moore
Publisher:
ISBN:
Category :
Languages : en
Pages : 190
Get Book Here
Book Description
Author: Wade H. Shafer
Publisher: Springer Science & Business Media
ISBN: 1468449192
Category : Science
Languages : en
Pages : 314
Get Book Here
Book Description
Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1 957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 28 (thesis year 1 983) a total of 10,661 theses titles from 26 Canadian and 197 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 28 reports theses submitted in-1983, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 9
Get Book Here
Book Description
Deformation mechanisms and the role of interfaces in deformation twinning of a two-phase [TiAl /Ti3Al(?2)] lamellar alloy creep deformed at elevated temperatures have been investigated. Since the multiplication of lattice dislocations within both? and?2 lamellae is very limited at a low stress level due to a refined lamellar microstructure, the glide of interfacial dislocations on both?/?2 and?/? interfaces (i.e interface sliding) becomes an important deformation mode. Obstacles such as impinged lattice dislocations can impede the movement of interfacial dislocations, which glide in a cooperative fashion along the lamellar interfaces. The impediment of dislocation motion subsequently causes a dislocation pile-up in front of obstacles as creep strain accumulates. When the crystals deform at high stress level, deformation twinning becomes a predominant deformation mode. Deformation twins are found to nucleate from the interfaces as a result of a local stress concentration generated from dislocation pile-ups. It is suggested that the deformation twinning in lamellar TiAl/Ti3Al crystals can be vieived as a stress relaxation process for the concentration of stress at the head of each dislocation pile-up. An interface-assisted twinning mechanism is accordingly proposed and discussed.
Author: University of Illinois at Urbana-Champaign. Office of Engineering Publications
Publisher:
ISBN:
Category : Engineering
Languages : en
Pages : 332
Get Book Here
Book Description
Author: National Science Foundation (U.S.)
Publisher:
ISBN:
Category : Federal aid to research
Languages : en
Pages : 258
Get Book Here
Book Description
Author: Carlyn R. LaRosa
Publisher:
ISBN:
Category : Alloys
Languages : en
Pages : 136
Get Book Here
Book Description
High entropy alloys are a relatively new class of multicomponent alloys which exhibit a remarkable combination of strength, ductility, and fracture toughness. There are two general classes of high entropy alloys: 3d-transition metal high entropy alloys and refractory element high entropy alloys. The former has garnered considerable interest for applications at lower temperatures, while the latter is typically developed for high-temperature applications. Understanding the deformation mechanisms operative in these materials is central to improving their mechanical performance. Here, we present our efforts to answer some of these questions. First, we show that the exceptional mechanical properties of CrCoNi, a ternary derivative of the widely studied CrMnFeCoNi high entropy alloy, are the result of a magnetically-driven phase transformation. While previously thought to have a single-phase fcc crystal structure, we have shown the existence of a nano-structured hcp phase which is unique to CrCoNi among the CrMnFeCoNi parent high entropy alloy and its derivatives. We also provide a mechanistic picture for the formation of this phase transformation and show that it can be formed both homogeneously and heterogeneously. We also demonstrate how dislocation interactions with existing phase boundaries can produce both strength- and ductility-enhancing mechanisms. Next, we present our newly developed bond energy model for the prediction of stacking fault energies in concentrated alloys, such as high entropy alloys. We introduce the conceptual basis of our model, explain how to determine the requisite bond energies, and apply our models to four different concentrated alloys. We show that our model can predict stacking fault energies for the intrinsic stacking fault, extrinsic stacking fault, twin formation, and hcp formation which are in good agreement with the values calculated using density functional theory, despite a small fraction of the computational cost. We discuss how to further expand our model to provide additional utility. Finally, we apply MonteCarlo and Multi-Cell Monte Carlo methods for phase prediction in refractory high entropy alloys and refractory superalloys. We apply the Monte Carlo method for the phase prediction of AlMoNbTi and AlHfNbTi, which have both been shown experimentally to have the B2 crystal structure. While the predictions for the former were in accordance with previous reports, the latter was shown to be unstable in the bcc crystal structure. We subsequently apply the Multi-Cell Monte Carlo method for phase prediction of a Al5.9Nb23.5Ta23.5Ti23.5Zr23.5 refractory superalloy, which has a two-phase A2+B2 microstructure. Phase separation was predicted, and the compositions of the two phase were similar to those reported experimentally. However, while the Nb- and Ta-rich simulation cell crystallized in a disordered A2 phase, as expected, the Zr-rich simulation cell was unstable. The instability of this Zr-rich phase and theAlHfNbTi alloy would suggest the inclusion of the anharmonic vibrational energy is an important component for alloys containing group 4 elements, which are unstable in the bcc crystal structure in their elemental forms. We discuss future benchmarking efforts and provide recommendations for future studies of phase prediction to develop new two-phase refractory superalloys.
![Creep of a Fine-grained, Fully-lamellar, Two-phase TiAl Alloy at 760[degree]C. PDF](https://books.google.com/books/content/images/frontcover/hdwHkAEACAAJ?fife=w80-h100)
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
Creep of a TiAl alloy, having a composition of Ti-47Al-2Cr-2Nb (in atom%) and a fine-grained, fully-lamellar structure, was carried out at 760 C and stresses between 69--723 MPa. It was found that, in addition to having good room temperature properties, the alloy exhibits higher creep resistance than other TiAl alloys with a similar composition. Both the creep data and microstructures of the alloy suggest that there exists a change in deformation mechanism from a glide-controlled process at high stresses to a recovery-controlled process at low stresses. Also, microstructural evidence indicates that the rate-controlling recovery mechanism is the climb of dislocation segments pinned by ledges at[gamma]/[alpha][sub 2] interfacial boundaries.
Author: Michael E. Kassner
Publisher: Butterworth-Heinemann
ISBN: 0080994326
Category : Technology & Engineering
Languages : en
Pages : 357
Get Book Here
Book Description
Although the present edition of Fundamentals of Creep in Metals and Alloys remains broadly up to date for metals, there are a range of improvements and updates that are either desirable, or required, in order to ensure that the book continues to meet the needs of researchers and scholars in the general area of creep plasticity. Besides updating the areas currently covered in the second edition with recent advances, the third edition will broaden its scope beyond metals and alloys to include ceramics, covalent solids, minerals and polymers, thus addressing the fundamentals of creep in all basic classes of materials. - Numerous line drawings with consistent format and units allow easy comparison of the behavior of a very wide range of materials - Transmission electron micrographs provide direct insight into the basic microstructure of metals deforming at high temperatures - Extensive literature review of about 1000 references provides an excellent overview of the field
Author:
Publisher:
ISBN:
Category : Chemistry
Languages : en
Pages : 2540
Get Book Here
Book Description
