Download or read book Quench Sensitivity in 6xxx Series Aluminium Alloys written by Katharina Strobel and published by . This book was released on 2013 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quench sensitivity, the dependence of strength and hardness on the cooling rate after extrusion or solution treatment, limits the applications of extrusions of heat treatable aluminium alloys. Reduced properties in slow cooled samples have long been attributed to the loss of solute on heterogeneous nucleation sites during cooling. While minimum cooling rates to avoid precipitation of Mg-Si-containing phases and reduced properties have been mapped out for a broad range of commercial alloys, little is understood about the physical mechanisms leading to quench sensitivity. In this investigation the difference in hardness evolution between slow cooled and fast quenched samples of various commercial and model Al-Mg-Si alloys has been determined for a broad range of natural and artificial ageing times. This has demonstrated that the artificial ageing response of fast quenched samples differs greatly from the artificial ageing response of slow cooled samples. In contrast to fast cooled samples, where natural ageing has a negative effect, the artificial ageing response of slow cooled samples is less dependent on natural ageing time. As a result, hardness differences between fast and slow cooled samples is large during artificial ageing after short natural ageing times, but small after long natural ageing times, such that quench sensitivity strongly varies. In order to explain this phenomenon, the cooling rate dependent microstructural development has been investigated using hardness measurements, electron microscopy (SEM and TEM), differential scanning calorimetry (DSC) and positron annihilation lifetime spectroscopy (PALS). From TEM investigations and theoretical considerations of the diffusion range it has been determined that solute is only lost from a limited region around the non-hardening precipitates forming during cooling on secondary dispersoids. The increased age hardening rate in fast cooled samples after short natural ageing times is therefore the result of a high vacancy supersaturation rather than a high solute supersaturation compared to slow cooled samples. Non-equilibrium vacancies appear to act as precipitation sites for the precursor of the strengthening [beta]"--Precipitates. In slow cooled samples the formation of [beta]"-precipitates seems to be suppressed. In lean alloys with a low solute content, such as the investigated AA6060, the age hardening response is almost independent of the cooling rate. Small additions of Cu or changes in the Mg:Si-ratio in alloys with a combined Mg+Si-content greater than 1 wt.% have little effect on precipitation of non-hardening phases during cooling, but affect natural and artificial ageing behaviour. The cooling rate after extrusion or solution treatment was also found to affect whether natural ageing has a negative effect or not. In fast cooled samples of Al-Mg-Si alloys with combined Mg+Si-contents greater than 1 wt.% the decrease in ageing kinetics due to the decrease of non-equilibrium vacancies with increasing natural ageing time contributes to the negative effect. In slow cooled samples the initial number of quenched-in vacancies is low, such that ageing kinetics are independent of the natural ageing time.
Download or read book Quench Sensitivity of 6xxx Aluminum Alloys written by Adam Assaad and published by . This book was released on 2016 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of AA6xxx series alloys continues to grow with the increasing demand for more fuel efficient vehicles. AA6xxx series alloys are commonly used in automotive applications because of their extrudability and good strength/weight ratio. As the use of these alloys becomes more prominent, new technologies must be developed to improve them. Chromium has been used as an alloy addition to AA6xxx alloys to control the grain structure by creating dispersoids that pin grains and limit grain growth and thereby improve the mechanical properties of aluminum alloys. However, the addition of chromium and other transition metals can have some adverse effects on aluminum alloys including making them more quench sensitivity after processing. The objective of this research was to do study the effect of alloy composition including the effect of Cr on the quench sensitivity of AA6xxx aluminum alloys, and to measure the effect of quench sensitivity on subsequent mechanical properties both in the T4 (naturally aged) and T6 (artificially aged) temper conditions. The experiments were conducted using a standard Jominy quenched end test and also included tensile testing for various quenching conditions for the AA6xxx alloys studied. The Jominy test provided a large range of cooling rates, which provided data for the variation in hardness as a function of cooling history. Supplemental tests were done on the alloys using tensile samples and water, air and furnace cooling to see what effect these cooling histories had on mechanical properties. It was found that the addition of Cr and Mn to the AA6xxx alloy caused an increase in quench sensitivity, and the cooling rate during quenching had a strong effect on the mechanical properties. It was found that AA6063 can be air cooled or cooled at a rate of ~0.8°C/s (48°C/s) after extrusion to retain 90% of its peak yield strength. Composition 1 (high Cr) must be cooled at a rate of at least ~25°C/s (1500 °C/min) in order to retain 90% of its peak yield strength. Composition 3 (high Cr and Mg) must be cooled at a rate of ~30°C/s in order to retain 90% of its peak yield strength.
Download or read book Investigation of the Quench and Heating Rate Sensitivities of Selected 7000 Series Aluminum Alloys written by and published by . This book was released on 2007 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The quench sensitivity of AA7136 has been experimentally investigated using Jominy end quench and test coupons of various heat treatments. It was found that this alloy is not quench sensitive. In addition, the effects of heating rate on both solution and aging treatments on AA7136 and AA7075 were determined using a newly developed reverse Jominy heating test. It was observed that hardness was reduced after rapid heating during aging and hardness increased slightly after rapid heating during solutionizing. These results are discussed in terms of microstructural developments.
Download or read book Quench Sensitivity of Aluminum Alloys written by Murat Tiryakioḡlu and published by . This book was released on 1999 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quench Sensitivity of Aluminium Alloys written by Benjamin Milkereit and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: For aluminium alloys, precipitation strengthening is controlled by age-hardening heat treatments, including solution treatment, quenching, and ageing. Quenching is considered a critical step, because detrimental quench-induced precipitation must be avoided to exploit the full age-hardening potential of the alloy. This work presents a comprehensive report on the solid-solid phase transformation kinetics in Al alloys covering to a vast extent quench-induced precipitation during continuous cooling over a dynamic cooling rate range of ten orders of magnitude.eng
Download or read book Quench Sensitivity of 7xxx Series Aluminium Alloys written by Yong Zhang and published by . This book was released on 2014 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: The quench sensitivity of high strength 7xxx series aluminium alloys becomes an increasingly important issue as the product thickness increases. Due to the nature of thermal conduction, the centre layer of a thick aluminium plate experiences a slower cooling rate than the surface. This can lead to variations in properties such as strength, corrosion resistance and fracture toughness across the thickness of a plate. The objective of this work was to study the quench-induced precipitation behaviour in different 7xxx alloys with systematic changes of alloy composition and processing history. Detailed microstructural analysis has been carried out using SEM, EBSD, TEM and HAADF-HRTEM. Vickers hardness values, electrical conductivities and the precipitation heats determined from differential scanning calorimetry (DSC) were measured for a wide range of different cooling rate conditions to evaluate the different quench sensitivity behaviours. The main findings from this work are as follows:1.The results show that the Al3Zr dispersoids in recrystallised grains can become preferential nucleation sites for quench-induced precipitates in air cooling condition. The microstructural characterisation shows that the Al3Zr dispersoids tend to maintain their metastable structure and orientation when recrystallisation occurs. This causes them to lose coherency with the matrix after recrystallisation and thereby causes them to become more potent heterogeneous nucleation sites for quench-induced precipitation. It should be noted that incoherent Al3Zr dispersoids are not the only preferential sites for quench-induced precipitates. They can precipitate out at grain/subgrain boundaries in air cooling condition. However, the current research still demonstrates that materials containing a higher fraction of recrystallisation will lead to a significant increase of quench sensitivity.2.The precipitation heats for quench-induced precipitates have been studied using a specialised DSC technique over a wide range of cooling rate conditions. A continuous cooling precipitation (CCP) diagram for commercially produced alloy 7150 has been developed based on a combination of DSC measurements, microstructure analysis and hardness testing. The results show that there are three main quench-induced precipitation located in different temperature ranges. It is demonstrated that the high temperature reaction from about 350 to 470 °C corresponds to S-phase (Al2CuMg), the medium temperature reaction from about 200 to 400 °C corresponds to M-phase (MgZn2) and the low temperature reaction from about 250 to 150 °C corresponds to a unique platelet phase containing both Cu and Zn. The critical cooling rates were determined to be 3 K/s for the S-phase, 10 K/s for the M-phase, and 300 K/s for the unique platelet phase in alloy 7150.The platelet phase has not been previously reported for alloy 7150. The platelets precipitate with a high aspect ratio and have a hexagonal structure (a=0.429 nm, c=1.385 nm) according to HAADF-STEM images. It is shown that this platelet phase can contribute to strengthening. 3.It was shown that the surface layer of a 7150 thick plate is more sensitive to cooling rate than the centre layer. This can be ascribed to a relatively higher degree of recrystallisation in the surface layer. Therefore there are more nucleation sites for quench-induced precipitates in the same cooling condition. It was confirmed with DSC analysis that the precipitation heat values for the surface layer are higher than for the centre layer, demonstrating that there is more quench-induced precipitation occuring in the surface layer.4.A number of CCP diagrams were developed for alloys 7085, 7037, 7020 and 7055 with systematic changes in alloy composition. It is demonstrated that the quench sensitivity generally increases with increasing total alloy content. Therefore alloy 7020 exhibits the lowest quench sensitivity when compared with the other studied alloys. It is noted that the amount of M-phase increases with increasing Zn content. Therefore alloys 7085, 7037 and 7055 can precipitate more M-phase during slow cooling than alloys 7150 and 7020. However, the precipitation of S-phase during continuous cooling was found to be significantly suppressed with increasing Zn/Mg ratio. Quench factor analysis (QFA) also indicates that higher k3 values can be found for the higher Zn/Mg ratio alloys 7085 and 7037, suggesting that the energy required to form a nucleus is higher in these two alloys. This is in agreement with experimental observations that these two alloys contained less S-phase and exhibited relatively low quench sensitivities.It was shown that the CCP diagrams provide a useful method of quantifying the quench sensitivities of different alloys. The CCP diagrams can also facilitate engineers to design and optimise industrial cooling process more effectively. However, it requires a deep understating of the quench-induced precipitation to develop a reliable CCP diagram for a given alloy, i.e. what types of quench-induced precipitation reactions happen, where they preferentially nucleate and how many much precipitation occurs during the cooling process. The current research therefore shows that the quench sensitivity of a 7xxx alloy can be decreased by decreasing the degree of deformation, decreasing the fraction of recrystallisition, decreasing the total grain boundary area, decreasing the number of incoherent dispersoids, decreasing the total alloying content, increasing the Zn/Mg ratio and decreasing the Cu content.
Download or read book Quench Sensitivity of Aluminum Alloys written by Dr. Murat Tiryakioglu and published by . This book was released on 2000 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Light Metals 2022 written by Dmitry Eskin and published by Springer Nature. This book was released on 2022-02-05 with total page 1088 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Light Metals symposia at the TMS Annual Meeting & Exhibition present the most recent developments, discoveries, and practices in primary aluminum science and technology. The annual Light Metals volume has become the definitive reference in the field of aluminum production and related light metal technologies. The 2022 collection includes contributions from the following symposia: • Alumina and Bauxite • Aluminum Alloys, Processing and Characterization • Aluminum Reduction Technology • Aluminum Reduction Technology Joint Session with REWAS: Decarbonizing the Metals Industry • Cast Shop Technology • Electrode Technology for Aluminum Production • Primary Aluminum Industry—Energy and Emission Reductions: An LMD Symposium in Honor of Halvor Kvande • Recycling and Sustainability in Cast Shop Technology: Joint Session with REWAS 2022
Download or read book Extrusion of Aluminium Alloys written by T. Sheppard and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years the importance of extruded alloys has increased due to the decline in copper extrusion, increased use in structural applications, environmental impact and reduced energy consumption. There have also been huge technical advances. This text provides comprehensive coverage of the metallurgical, mathematical and practical features of the process.
Download or read book Mechanical Properties of Zirconium written by F. D. Rosi and published by . This book was released on 1952 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Thermal Analysis and Calorimetry written by and published by Elsevier. This book was released on 2018-03-12 with total page 862 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Thermal Analysis and Calorimetry: Recent Advances, Techniques and Applications, Volume Six, Second Edition, presents the latest in a series that has been well received by the thermal analysis and calorimetry community. This volume covers recent advances in techniques and applications that complement the earlier volumes. There has been tremendous progress in the field in recent years, and this book puts together the most high-impact topics selected for their popularity by new editors Sergey Vyazovkin, Nobuyoshi Koga and Christoph Schick—all editors of Thermochimica Acta. Among the important new techniques covered are biomass conversion; sustainable polymers; polymer nanocompsoties; nonmetallic glasses; phase change materials; propellants and explosives; applications to pharmaceuticals; processes in ceramics, metals, and alloys; ionic liquids; fast-scanning calorimetry, and more. - Features 19 all-new chapters to bring readers up to date on the current status of the field - Provides a broad overview of recent progress in the most popular techniques and applications - Includes chapters authored by a recognized leader in each field and compiled by a new team of editors, each with at least 20 years of experience in the field of thermal analysis and calorimetry - Enables applications across a wide range of modern materials, including polymers, metals, alloys, ceramics, energetics and pharmaceutics - Overviews the current status of the field and summarizes recent progress in the most popular techniques and applications
Download or read book Quench Sensitivity of Hot Extruded 6061 T6 and 6069 T6 Aluminum Alloys written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study is to investigate the quench sensitivity of mechanical properties of hot extruded 6061 and 6069 aluminum alloys. The relationship between mechanical properties and quench delzty time at various temperatures between 200-500 C was determined. It was concluded that the 6069-T6 was somewhat more quench sensitive than 6061, which may be consistent with the composition difference.
Download or read book Quench sensitivity in 7xxx Aluminum Alloys written by Orval Henry Hilliard and published by . This book was released on 1969 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aluminum written by John E. Hatch and published by ASM International. This book was released on 1984-01-01 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive information for the American aluminium industry Collective effort of 53 recognized experts on aluminium and aluminium alloys Joint venture by world renowned authorities-the Aluminium Association Inc. and American Society for Metals. The completely updated source of information on aluminium industry as a whole rather than its individual contributors. this book is an opportunity to gain from The knowledge of the experts working for prestigious companies such as Alcoa, Reynolds Metals Co., Alcan International Ltd., Kaiser Aluminium & Chemical Corp., Martin Marietta Laboratories and Anaconda Aluminium Co. It took four years of diligent work to complete this comprehensive successor to the classic volume, Aluminium, published by ASM in 1967. Contents: Properties of Pure Aluminum Constitution of Alloys Microstructure of Alloys Work Hardening Recovery, Recrystalization and Growth Metallurgy of Heat Treatment and General Principles of Precipitation Hardening Effects of Alloying Elements and Impurities on Properties Corrosion Behaviour Properties of Commercial Casting Alloys Properties of Commercial Wrought Alloys Aluminum Powder and Powder Metallurgy Products.
Download or read book Quench Sensitivity of Airframe Aluminium Alloys written by H. J. Kolkman and published by . This book was released on 1988 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Light Metals 2021 written by Linus Perander and published by Springer Nature. This book was released on 2021-02-23 with total page 1049 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Light Metals symposia at the TMS Annual Meeting & Exhibition present the most recent developments, discoveries, and practices in primary aluminum science and technology. The annual Light Metals volume has become the definitive reference in the field of aluminum production and related light metal technologies. The 2021 collection includes contributions from the following symposia: · Alumina and Bauxite · Aluminum Alloys, Processing, and Characterization · Aluminum Reduction Technology · Aluminum Reduction Technology Across the Decades: An LMD Symposium Honoring Alton T. Tabereaux, Halvor Kvande and Harald A. Øye · Cast Shop Technology · Electrode Technology for Aluminum Production
Download or read book A Study on Quench Sensitivity and Validation of JEQ for Cast Aluminum Alloys A356 and B319 written by Sachin Mehta and published by . This book was released on 2001 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:
