Download or read book The Flow and Fracture of A1 High Mg Mn Alloys at High Temperatures and Strain Rates written by Karl Lintermanns Fander and published by . This book was released on 1984 with total page 2524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Strain Rate and Temperature on Fracture and Damage of Magnesium Alloy AZ31B written by Ana Karina Rodriguez Atencio and published by . This book was released on 2015 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to their low density and high specific strength, magnesium and its alloys are structural metals attractive for the aerospace and automotive industries. However, wide spread use of wrought magnesium is challenged by its limited formability at low temperature compared to aluminum and steel. This results in costly production and processing of sheet and plate material. Extensive research has been carried out on deformation mechanisms, mechanical characterization, new processing routes and alloying systems in order to overcome these limitations. However, the available literature on damage and fracture is limited. In particular, the effects of temperature and strain rate on damage and fracture remain unexplored. The purpose of this study is to investigate this effects on damage accumulation to fracture in a magnesium alloy. Twin roll cast magnesium plates of AZ31B were used to that end. An extensive experimental campaign of tensile tests at various strain rates and temperatures was performed with this aim. In addition, a series of interrupted tests were carried out to investigate the microscopic damage mechanisms by means of optical and scanning electron microscopy. The materials were found to have a positive strain rate sensitivity and showed thermal softening. Microstructural studies revealed an increased propensity to form deformation twinning at higher strain rates and lower temperatures, as expected. The fracture behavior was characterized in terms of the work to fracture (Wf). Wf exhibited a maximum at some strain rate dependent on temperature. Conversely, at a fixed strain rate, Wf showed a maximum at a temperature dependent on strain rate. To understand these trends, microscopy analysis was carried out on selected conditions. Under all the conditions examined, two main damage sites were identified: second phase particles and twinning. However, the propensity for twin-sized cracks was highest under conditions where the density of twinning was lowest. Different scenarios are explored in order to rationalize this behavior. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155147
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1981 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reactor Materials written by and published by . This book was released on 1969 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Magnesium Alloys written by Frank Czerwinski and published by BoD – Books on Demand. This book was released on 2014-11-05 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnesium alloys with their unique physical and chemical properties are important candidates for many modern engineering applications. Their density, being the lowest of all structural metals, makes them the primary choice in global attempts aimed at reducing the weight of transportation vehicles. However, magnesium also creates challenges at certain stages of raw alloy melting, fabrication of net-shape components and their service. The first one is caused by very high affinity of magnesium to oxygen, which requires protective atmospheres increasing manufacturing cost and heavily contributing to greenhouse gas emissions. The second challenge relates to very high corrosivity of liquid magnesium towards materials it contacts. This imposes restrictions on the selection of materials used to contain, transfer or process molten magnesium during manufacturing operations. A mixture of unique benefits and serious challenges of magnesium alloys in solid and liquid states described here makes the book very useful for a broad audience of scientists and engineers from academia and industry.
Download or read book Aluminum and Aluminum Alloys written by Joseph R. Davis and published by ASM International. This book was released on 1993-01-01 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt: This one-stop reference is a tremendous value and time saver for engineers, designers and researchers. Emerging technologies, including aluminum metal-matrix composites, are combined with all the essential aluminum information from the ASM Handbook series (with updated statistical information).
Download or read book Mechanical Properties written by and published by . This book was released on 1975 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Twinning on Texture and Strain Hardening in Magnesium Alloys Subjected to Different Strain Paths written by Lan Jiang and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The evolution of flow stress and microstructure during the deformation of two Mg-based (+Al, Mn, Zn) alloys has been studied under various conditions of temperature and strain rate. The tested materials were taken from AZ31 and AM30 extruded tubes. The effect of twinning was investigated by using uniaxial tension, uniaxial compression and ring hoop tension testing. Strain path change testing, i.e. tensile prestraining followed by uniaxial compression, was carried out to study the role of contraction and double twins on the subsequent deformation. Optical metallography and EBSD techniques were employed to study the microstructural development. The first part of the investigation focused on the flow stresses developed during deformation along the three different strain paths. It was found that at low temperatures (≤200°C), the flow behaviors are mainly controlled by twinning. At temperatures above 200°C but below 350°C, especially at a strain rate of 0.001s-1, the deformation is largely accommodated in partially dynamically recrystallized regions. As a result, the formation of voids in these regions causes premature fracture. The second part focused on the twinning behavior displayed during deformation to a strain of 0.15. The results indicate that the initial extrusion texture plays an important role in the formation of different types of twins and that the twinning behavior also depends on the strain path. {10-11} contraction and {10-11}-{10-12} double twinning are the dominant twinning mechanisms in uniaxial tension, while {10-12} extension twinning prevails in uniaxial compression and ring hoop tension testing. Grain size, temperature, strain and strain rate all have significant effects on the volume fraction of contraction and double twins. There is a sigmoidal relationship between the volume fraction of extension twins and the strain. The effect of grain size (in this grain size range) on the volume fraction of extension twins is small. For a given strain, at high strain rates, temperature does not have much influence on the volume fraction (below 200°C). In the third part of the investigation, the deformation texture associated with twinning was examined. The near 100% volume fraction of {10-12} extension twins gives rise to significant texture changes. By contrast, {10-11} contraction and {10-11}-{10-12} double twinning only make a small contribution to texture change due to the limited volume fraction of twinned material. Schmid factor analysis indicates that, for the {10-12} extension twins, all variants that are favorably oriented (i.e. with the highest SF values) can undergo rapid and complete twinning. For the {10-11} contraction twins, only variants in the TD component (11-20) 10-10 follow the SF criterion. The development of internal stresses, which somehow particularly affect the RD component (10-10) 0001 grains, may explain this difference. In the final part of the investigation, the effects of twinning on the strain hardening behavior and on ductility were studied. Different behaviors are shown to be responsible for the sharply contrasting strain hardening characteristics of the experimental flow curves. When a certain volume fraction (≥20% in the present study) is reached, contraction and double twinning generate net softening effects. Nevertheless, when they interact with extension twins, the hardening effect may predominate. On the other hand, extension twinning generally introduces a hardening effect. The hardening effect due to twin boundaries appears to be stronger than that from the volume fraction of extension twins, since the hardening associated with extension twinning cannot be explained by the volume fraction alone. Depending on the deformation conditions, twinning can be detrimental to the formability on the one hand but it can also be beneficial on the other."--
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1969-07 with total page 1000 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metals Abstracts written by and published by . This book was released on 1995 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Serrated Flow and Enhanced Ductility in Coarse grained Al Mg Alloys written by Ehab Samuel and published by . This book was released on 2008 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Response Texture Evolution and Fracture of a Rare earth containing Magnesium Alloy Sheet ZEK100 at Different Strain Rates and Temperatures written by Saadi Habib and published by . This book was released on 2019 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnesium alloys have been at the forefront as possible alternatives to conventional materials such as aluminum and steel for their high specific-strength. However, magnesium alloys exhibit anisotropy, tension-compression asymmetry, and quasi-brittle fracture at ambient temperature, which is exacerbated at high strain rates. It is well known that alloying with rare-earth elements can improve the low uniaxial ductility in comparison with conventional magnesium alloys. Therefore, the mechanical response and texture evolution of a rare-earth-containing magnesium alloy sheet, ZEK100, are investigated under different loading conditions to characterize the anisotropy, tension-compression asymmetry, strain rate sensitivity and thermomechanical response. A reduced-order crystal plasticity model that defines extension twinning, basal a slip, and non-basal slip as the deformation mechanisms, is used to model the experimental results and to give an insight in the active deformation mechanism. In addition, the fracture behavior of ZEK100 is also investigated at different stress states and strain rates. A variety of sample geometries loaded along different processing directions are used to achieve different stress states and deformation mechanisms. Surface strain maps for all the specimens are measured using the digital image correlation (DIC) technique to quantify the strain at fracture. ZEK100 exhibits larger strain at fracture across the gage section of the test specimens aligned with the transverse direction (TD) than specimens aligned with the rolling direction (RD); however, the opposite is shown for the local strain measurements at fracture. Therefore, the crystal plasticity model is used to simulate each loading condition to understand the anisotropic ductile fracture behavior of ZEK100. Using the stress states and deformation mechanisms from the simulations, a novel anisotropic criterion is developed which is an extension of the Hosford-Coulomb (HC) fracture model. The new anisotropic criterion accounts for the role of different deformation mechanisms on the anisotropic fracture response of ZEK100.
Download or read book Application of Rate temperature Parameters to Tensile Data for Magnesium Alloys and a Relation Between the Larson Miller Constant and the Activation Energy written by Charles R. Manning and published by . This book was released on 1960 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ASM Handbook written by ASM International. Handbook Committee and published by ASM International(OH). This book was released on 1990 with total page 1352 pages. Available in PDF, EPUB and Kindle. Book excerpt: These volumes cover the properties, processing, and applications of metals and nonmetallic engineering materials. They are designed to provide the authoritative information and data necessary for the appropriate selection of materials to meet critical design and performance criteria.
Download or read book Warm Formability of Aluminum magnesium Alloys written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Manufacturers have become increasingly interested in near-net-shape forming of aluminum alloys as a means to reduce production costs and the weight of aircraft and automotive structures. To achieve the ductilities required for this process, we have examined extended ductility of Al-Mg alloys in the warm forming, or Class I creep, regime. We have studied a high-purity, binary alloy of Al-2.8Mg and ternary alloys of Al-xMg-0.5Mn with Mg concentrations from 1.0 to 6.6 wt. %. Tensile tests, including strain rates-change tests, have been performed with these materials at temperatures of 300 and 400C over a range 10[sup [minus]4] to 2 [times] 10[sup [minus]2] s[sup [minus]1]. A maximum tensile failure strain of 325% for the binary alloy and a maximum of 125% in the ternary alloys have been measured. The experimental results have been used to evaluate the effects of solute concentration, microstructure, temperature, and strain rate on flow stress ([sigma]), elongation to failure (e[sub f]), and strain-rate sensitivity (m) of these alloys.
Download or read book World Aluminum Abstracts written by and published by . This book was released on 1973 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Metallurgical Effects at High Strain Rates written by R. Rohde and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: A conference on Metallurgical Effects at High Strain Rates was held at Albuquerque, New Mexico, February 5 through 8, 1973, under joint sponsorship of Sandia Laboratories and the Physical Metallurgy Committee of The Metallurgical Society of AIME. This book presents the written proceedings of the meeting. The purpose of the conference was to gather scientists from diverse disciplines and stimulate interdisciplinary discussions on key areas of materials response at high strain rates. In this spirit, it was similar to one of the first highly successful con ferences on this subject held in 1960, in Estes Park, Colorado, on The Response of Metals to High Velocity Deformation. The 1973 conference was able to demonstrate rather directly the increased understanding of high strain rate effects in metals that has evolved over a period of roughly 12 years. In keeping with the interdisciplinary nature of the meeting, the first day was devoted to a tutorial session of invited papers to provide attendees of diverse backgrounds with a common basis of understanding. Sessions were then held with themes centered around key areas of the high strain rate behavior of metals.
