Download or read book Effects of Changes in Chemistry and Test Temperature on Deformation Behavior and Fatigue Properties of Al Based Amorphous Alloys written by Chun-Kuo Huang and published by . This book was released on 2011 with total page 203 pages. Available in PDF, EPUB and Kindle. Book excerpt: The extraordinary mechanical properties such as high strength, hardness, elasticity, and strength to density ratio, as well as good formability and shaping abilities make Al-based amorphous alloys good candidates for structural applications. In this dissertation, the effects of changes in chemical composition of Al-Gd-Ni-X (X= transition metals) were investigated. Three aspects of properties were examined: thermal stability, deformation behavior, and fatigue properties. Systematic additions of Fe and Co significantly improved Tg and Tx1 of the base Al87Gd6Ni7 amorphous alloy since Fe and Co exhibit a negative heat of mixing with Al. However, the value of (i.e. Tx - Tg) was not changed significantly over the range of alloying additions investigated. The deformation behavior of Al-Gd-Ni-X ribbons was determined by high temperature micro-hardness tests and dynamic mechanical analysis (DMA). Although these ribbons exhibited high hardness/viscosity at room temperature, a distinct reduction near their Tg was observed, with subsequent increases when the test temperature passed Tx. Such behavior and separate TEM analysis indicated that microstructural evolution occurred at this temperature. The deformation behavior also was studied by tensile tests at various temperatures. A transition from inhomogeneous flow to more homogeneous flow was obtained at low strain rates upon approaching Tg, while the deformation behavior at different strain rates and temperatures was captured in a deformation map. In addition, the fatigue performance was examined at both R= -1 and R= 0 conditions. It was demonstrated that the substitution for Al by Fe and Co additions increased the stress amplitude at the fatigue limit from 240 MPa for Al87Gd6Ni7 to 397 MPa for Al86Gd6Ni7Co1 when tested at R= -1. Conducting fatigue tests at R= 0 revealed that tensile mean stresses produced a detrimental effect on the fatigue performance, but not as great as that exhibited in commercial aluminum alloys. It also was demonstrated that the improvement of high cycle fatigue performance of higher alloyed glasses may be a result of their higher Tg, providing a lower value of the ratio of the test temperature to Tg. The importance of this was checked by conducting fatigue tests at lower test temperatures (i.e. different values of T/Tg). The increases in the Fe/Co level that produced improvements in the HCF behavior are partly attributed to the lower T/Tg present during fatigue testing of the highly alloyed ribbons.

Download or read book Properties of Aluminum Alloys written by John Gilbert Kaufman and published by ASM International. This book was released on 2008-01-01 with total page 569 pages. Available in PDF, EPUB and Kindle. Book excerpt: A compilation of data collected and maintained for many years as the property of a large aluminum company, which decided in 1997 to make it available to other engineers and materials specialists. In tabular form, presents data on the tensile and creep properties of eight species of wrought alloys and five species of cast alloys in the various shapes used in applications. Then looks at the fatigue data for several alloys under a range of conditions and loads. The data represent the typical or average findings, and though some were developed years ago, the collection is the largest and most detailed available. There is no index.

Download or read book Environmental Corrosion fatigue Behavior of Aluminum Alloys written by D. N. Williams and published by . This book was released on 1970 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of environment on fatigue behavior are quite intimately related to such test variables as stress intensity, cyclic frequency, and temperature. The effect of these variables has been shown to be quite complex. However, a consistent pattern of behavior is beginning to emerge which, it is hoped, will lead to a considerably changed understanding of the corrosion-fatigue process. It is considered probable that an increased understanding of the corrosion-fatigue process will also contribute measureably to an improved understanding of general fatigue processes. Material variables such as composition, directionality of properties, and microstructure, have important effects on corrosion-fatigue behavior of aluminum alloys. However, it appears that these variables, at least in gaseous environments, may be important largely because of their effects on the mechanical behavior of aluminum alloys. On the other hand, studies in seawater suggest that these variables become increasingly important as the corrosive nature of the environment increases. This memorandum discusses in detail the effects of both test variables and material variables on corrosion fatigue. In addition, current theories of corrosion-fatigue mechanisms are outlined, and several methods of preventing corrosion fatigue are suggested. (Author).

Download or read book Fatigue Behavior and Residual Stress Stability of Deep rolled Aluminium Alloys AA5083 and AA6110 at Elevated Temperature written by Patiphan Juijerm and published by kassel university press GmbH. This book was released on 2007 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Correlation of Literature on the Effect of Testing Temperature on the Mechanical Properties of Wrought Aluminum Base Alloys written by Helen R. Pritchard and published by . This book was released on 1955 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fatigue Behavior of A356 Aluminum Alloy written by Phalgun Nelaturu and published by . This book was released on 2016 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal fatigue is a recurring problem for metallurgists and materials engineers, especially in structural applications. It has been responsible for many disastrous accidents and tragedies in history. Understanding the micro-mechanisms during cyclic deformation and combating fatigue failure has remained a grand challenge. Environmental effects, like temperature or a corrosive medium, further worsen and complicate the problem. Ultimate design against fatigue must come from a materials perspective with a fundamental understanding of the interaction of microstructural features with dislocations, under the influence of stress, temperature, and other factors. This research endeavors to contribute to the current understanding of the fatigue failure mechanisms. Cast aluminum alloys are susceptible to fatigue failure due to the presence of defects in the microstructure like casting porosities, non-metallic inclusions, non-uniform distribution of secondary phases, etc. Friction stir processing (FSP), an emerging solid state processing technique, is an effective tool to refine and homogenize the cast microstructure of an alloy. In this work, the effect of FSP on the microstructure of an A356 cast aluminum alloy, and the resulting effect on its tensile and fatigue behavior have been studied. The main focus is on crack initiation and propagation mechanisms, and how stage I and stage II cracks interact with the different microstructural features. Three unique microstructural conditions have been tested for fatigue performance at room temperature, 150 °C and 200 °C. Detailed fractography has been performed using optical microscopy, scanning electron microscopy (SEM) and electron back scattered diffraction (EBSD). These tools have also been utilized to characterize microstructural aspects like grain size, eutectic silicon particle size and distribution. Cyclic deformation at low temperatures is very sensitive to the microstructural distribution in this alloy. The findings from the room temperature fatigue tests highlight the important role played by persistent slip bands (PSBs) in fatigue crack initiation. At room temperature, cracks initiate along PSBs in the absence of other defects/stress risers, and grow transgranularly. Their propagation is retarded when they encounter grain boundaries. Another major finding is the complete transition of the mode of fatigue cracking from transgranular to intergranular, at 200 °C. This occurs when PSBs form in adjacent grains and impinge on grain boundaries, raising the stress concentration at these locations. This initiates cracks along the grain boundaries. At these temperatures, cyclic deformation is no longer microstructure- dependent. Grain boundaries don't impede the progress of cracks, instead aid in their propagation. This work has extended the current understanding of fatigue cracking mechanisms in A356 Al alloys to elevated temperatures.

Download or read book Metal Plasticity and Fatigue at High Temperature written by Denis Benasciutti and published by MDPI. This book was released on 2020-05-20 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: In several industrial fields (such as automotive, steelmaking, aerospace, and fire protection systems) metals need to withstand a combination of cyclic loadings and high temperatures. In this condition, they usually exhibit an amount—more or less pronounced—of plastic deformation, often accompanied by creep or stress-relaxation phenomena. Plastic deformation under the action of cyclic loadings may cause fatigue cracks to appear, eventually leading to failures after a few cycles. In estimating the material strength under such loading conditions, the high-temperature material behavior needs to be considered against cyclic loading and creep, the experimental strength to isothermal/non-isothermal cyclic loadings and, not least of all, the choice and experimental calibration of numerical material models and the selection of the most comprehensive design approach. This book is a series of recent scientific contributions addressing several topics in the field of experimental characterization and physical-based modeling of material behavior and design methods against high-temperature loadings, with emphasis on the correlation between microstructure and strength. Several material types are considered, from stainless steel, aluminum alloys, Ni-based superalloys, spheroidal graphite iron, and copper alloys. The quality of scientific contributions in this book can assist scholars and scientists with their research in the field of metal plasticity, creep, and low-cycle fatigue.

Download or read book Fatigue of Materials III written by T. S. Srivatsan and published by John Wiley & Sons. This book was released on 2014-12-01 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains papers presented in the third international symposium titled Fatigue of Materials: Advances and Emergences in Understanding held during the Materials Science and Technology 2014 meeting in Pittsburgh, Pennsylvania, USA, in October 2014. The book contains contributions from engineers, technologists, and scientists from academia, research laboratories, and industries. The 19 papers are divided into five topical areas: Session 1: Aluminum Alloys Session 2: Ferrous Materials I Session 3: Ferrous Materials II Session 4: Composite Materials Session 5: Advanced Materials Session 6: Modeling The papers cover a broad spectrum of topics that represent the truly diverse nature of the subject of fatigue as it relates to the world of materials.

Download or read book Effect of Alloy Composition on the Hot Deformation Behavior Extrudability and Mechanical Properties of AA6XXX Aluminum Alloys written by Daniel Oghenekewhe Odoh and published by . This book was released on 2017 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: As automotive companies adjust to stricter environmental legislations, there is increased interest in the application of high specific strength alloys such as the AA6xxx aluminum alloys. In the near term, light weighting of vehicles through the use of high strength aluminum alloys is one solution to improve fuel efficiency. This research was performed to help understand the extrudability of some Al-Mg-Si alloys as well as the effect of extrusion conditions on final mechanical properties. The alloys studied were designed by General Motors (GM) and include variations in the Mg, Si and Cr contents. The research is primarily experimental in nature and consisted of measuring and modelling the hot flow stress behaviour of these alloys, performing both laboratory scale and industrial extrusion trials as well as mechanical and microstructural characterization of the extruded materials. The well-known Sellars-Tegart model was applied in development of constitutive equations for predicting the hot flow stress behavior of Al-Mg-Si alloys. The influence of hold time on Mg-Si solute content level during pre-deformation heating of an as-cast and homogenized Al-Mg-Si alloy was determined and the Mg-Si solute content (X) integrated into a constitutive equation for predicting the alloy's flow stress behavior during hot compression testing. The constitutive model predictions were observed to agree well with experimental data for the aluminum alloys tested in this research. The effect of extrusion processing condition, alloy composition and aging time on the extrudability, mechanical properties and fracture morphology as well as microstructure of Al-Mg-Si alloys was studied. The extrudability of the Al-Mg-Si alloys was observed to reduce with an increase in the Mg-Si content, presence of 0.2 wt % Cr and reduction in extrusion temperature. For laboratory extrusion trials, peripheral coarse grains were not observed in alloys containing Cr and Mn. The strength property in the T4, T5 and T6 conditions was observed to increase with Mg-Si content while 0.2 wt % Cr addition favors improved ductility. The alloys containing Cr were observed to exhibit ductile dimple fracture and a transgranular morphology while an intergranular fracture was observed in the Al-Mg-Si alloys with no Cr content. The strain rate sensitivity and anisotropic behaviors of an Al-Mg-Si alloy were determined by performing quasi-static tensile test at 0.001, 0.01 and 0.1 s-1 on heat treated (T4 and T6) profiles extruded in industrial scale extrusion equipment. The T4 alloy samples were observed to exhibit reduced anisotropic behavior in comparison with T6 samples. In this thesis, a more effective constitutive model for predicting the hot flow stress behavior of Al-Mg-Si alloys has been developed. The developed constitutive relation can be an effective tool for modeling forming processes such as extrusion and rolling, Also, a systematic through process (from extrusion processing to aging) investigation of the effect of alloy composition, extrusion and aging conditions on the final mechanical properties of Al-Mg-Si alloys has been performed.

Download or read book The Mechanisms of Dispersion Strengthening and Fracture in Al Based Xd tm Alloys Part 1 written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-23 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: The influence of reinforcement size, volume fraction, and matrix deformation behavior on room and elevated temperature strength; the fracture toughness; and the fatigue crack growth rate of metal matrix composites of Al-4(pct)Cu-1.5(pct)Mg with TiB2 were examined. The influence of reinforcement volume fraction was also examined for pure aluminum with TiB2. Higher TiB2 volume fractions increased the tensile yield strength at both room and elevated temperatures, and reduced the elongation to fracture. Tensile tests also indicate that small particles provided a greater increase in strength for a given volume fraction than larger particles, whereas elongation to fracture appeared to be insensitive to reinforcement size. Interparticle spacing appears to be the factor that controls the strength of these alloys, with the exact nature of the dependence relying on the nature of dislocation slip in the matrix (planar vs. diffuse). The isothermal aging response of the precipitation strengthened Al-4(pct)Cu-1.5(pct)Mg alloys was not accelerated by the presence of TiB2. Cold work prior to artificial aging created additional geometrically necessary dislocations which serve as heterogeneous nucleation sites leading to accelerated aging, a finer precipitate size, and an increase in the strength of the alloy. Aikin, R. M., Jr. Unspecified Center ALUMINUM ALLOYS; CRACK PROPAGATION; CRACKING (FRACTURING); DISPERSION STRENGTHENING; FRACTURE STRENGTH; METAL MATRIX COMPOSITES; TEMPERATURE EFFECTS; AGING (METALLURGY); CONCENTRATION (COMPOSITION); DEFORMATION; ELONGATION; FATIGUE (MATERIALS); ISOTHERMAL PROCESSES; NUCLEATION; PRECIPITATION HARDENING; TENSILE STRENGTH; YIELD STRENGTH...

Download or read book Hot Deformation and Processing of Aluminum Alloys written by Hugh J. McQueen and published by CRC Press. This book was released on 2016-04-19 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive treatise on the hot working of aluminum and its alloys, Hot Deformation and Processing of Aluminum Alloys details the possible microstructural developments that can occur with hot deformation of various alloys, as well as the kind of mechanical properties that can be anticipated. The authors take great care to explain and differenti

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on with total page 1050 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bulk Metallic Glasses written by C. Suryanarayana and published by CRC Press. This book was released on 2017-11-22 with total page 543 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflecting the fast pace of research in the field, the Second Edition of Bulk Metallic Glasses has been thoroughly updated and remains essential reading on the subject. It incorporates major advances in glass forming ability, corrosion behavior, and mechanical properties. Several of the newly proposed criteria to predict the glass-forming ability of alloys have been discussed. All other areas covered in this book have been updated, with special emphasis on topics where significant advances have occurred. These include processing of hierarchical surface structures and synthesis of nanophase composites using the chemical behavior of bulk metallic glasses and the development of novel bulk metallic glasses with high-strength and high-ductility and superelastic behavior. New topics such as high-entropy bulk metallic glasses, nanoporous alloys, novel nanocrystalline alloys, and soft magnetic glassy alloys with high saturation magnetization have also been discussed. Novel applications, such as metallic glassy screw bolts, surface coatings, hyperthermia glasses, ultra-thin mirrors and pressure sensors, mobile phone casing, and degradable biomedical materials, are described. Authored by the world’s foremost experts on bulk metallic glasses, this new edition endures as an indispensable reference and continues to be a one-stop resource on all aspects of bulk metallic glasses.

Download or read book The Mechanisms of Dispersion Strengthening and Fracture in Al based XD tm Alloys Part 1 written by and published by . This book was released on 1990 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: The influence of reinforcement size, volume fraction, and matrix deformation behavior on room and elevated temperature strength; the fracture toughness; and the fatigue crack growth rate of metal matrix composites of Al-4(pct)Cu-1.5(pct)Mg with TiB2 were examined. The influence of reinforcement volume fraction was also examined for pure aluminum with TiB2. Higher TiB2 volume fractions increased the tensile yield strength at both room and elevated temperatures, and reduced the elongation to fracture. Tensile tests also indicate that small particles provided a greater increase in strength for a given volume fraction than larger particles, whereas elongation to fracture appeared to be insensitive to reinforcement size. Interparticle spacing appears to be the factor that controls the strength of these alloys, with the exact nature of the dependence relying on the nature of dislocation slip in the matrix (planar vs. diffuse). The isothermal aging response of the precipitation strengthened Al-4(pct)Cu-1.5(pct)Mg alloys was not accelerated by the presence of TiB2. Cold work prior to artificial aging created additional geometrically necessary dislocations which serve as heterogeneous nucleation sites leading to accelerated aging, a finer precipitate size, and an increase in the strength of the alloy.

Download or read book Early Microstructural Evolution and Deformation Behavior in Solution Heat Treated Aluminum lithium Alloys written by Shelly Midori Miyasato and published by . This book was released on 1991 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Japanese Science and Technology 1983 1984 written by United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch and published by . This book was released on 1985 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt: