Al–Fe-based bulk quasicrystalline alloys with high elevated temperature strength

2000 ◽  
Vol 15 (12) ◽  
pp. 2737-2744 ◽  
Author(s):  
Hisamichi M. Kimura ◽  
Kenichiro Sasamori ◽  
Akihisa Inoue
Keyword(s):  
Elevated Temperature ◽  
Size Fraction ◽  
The United States ◽  
Decomposition Temperature ◽  
Mixed Structure ◽  
Elevated Temperature Strength ◽  
Average Grain Size ◽  
New Type ◽  
Strength Material ◽  
Ti Powder

An icosahedral (I) phase in coexistence with Al phase was found to precipitate in atomized Al93Fe3Cr2Ti2 and Al93Fe3Cr2V2 powders. The mixed structure was formed in the size fraction range up to 125 μm for the Al–Fe–Cr–V alloy, while the increase of the particle size to 125 μm for the Al–Fe–Cr–Ti powder led to the precipitation of Al23Ti9. The replacement of Cr by Mn for the Al93Fe3Cr2Ti2 powder caused a mixed structure of Al+I+Al23Ti9 +Al6Mn even for the ?26 mm powder. The formation tendency of the I-phase increased in the order of Al–Fe–Cr–V > Al–Fe–Cr–Ti > Al–Fe–Mn–Ti system. The decomposition temperature of the I-phase was about 790 K. The I particles were analyzed to have approximate compositions of Al84.2Fe7.0Cr6.3Ti2.5 and Al82.9Fe9.0Mn6.4Ti1.7, and the use of the analytical compositions enabled the formation of a mostly single I phase with an average grain size of 90 to 130 nm in the melt-spun state. Bulk I alloys in a cylindrical rod form were produced by extrusion of the atomized powders at 673 K and an extrusion ratio of 10. The extruded Al93Fe3Cr2Ti2 alloys exhibited good mechanical properties; i.e., σ 0.2 of 550 MPa, σ UTS of 660 MPa, and ε P of 4.5% at room temperature, and σ 0.2 of 330 MPa, σ UTS of 350 MPa, and ε P of 1.5% at 573 K. The high σ UTS exceeding 350 MPa at 573 K was superior to the final target of the United States Air Force and hence the I-based Al93Fe3Cr2Fe2 alloy is expected to be extended as a new type of high elevated temperature strength material.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

scholarly journals Enhancing elevated temperature strength of copper containing aluminium alloys by forming L12 Al3Zr precipitates and nucleating θ″ precipitates on them

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Surendra Kumar Makineni ◽  
Sandeep Sugathan ◽  
Subhashish Meher ◽  
Rajarshi Banerjee ◽  
Saswata Bhattacharya ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Aluminium Alloys ◽  
Elevated Temperature Strength

Urban electric railway management and operation in Britain and America 1900–14

Urban History ◽  
1989 ◽  
Vol 16 ◽  
pp. 22-37 ◽  
Author(s):  
M. D. Reilly
Keyword(s):  
United States ◽  
Capital Market ◽  
The United States ◽  
Comparative Performance ◽  
Transit System ◽  
Investment Projects ◽  
Industrial Sectors ◽  
Difficult Time ◽  
New Type ◽  
The Capital Market

The debate about the comparative performance of the British and American economies around the turn of the century has involved most industrial sectors. In the case of the railways, the argument goes back at least to 1887, when a critical analysis of English railway operations compared to those of the United States was published. For British railway companies, the years after 1900 were a particularly difficult time especially in the capital market, and many new investment projects were abandoned, although not solely because of adverse conditions in the capital market. A substantial number of these projects were probably of a marginal nature but the eighteen-year period between 1890 and 1908 also saw the development of a new type of railway – the urban rapid transit system. This was in response to two very different factors – the continuing growth of cities and the application of electric power in a form suitable for railway use. The spread of these systems in Britain paralleled their expansion in the United States.

Investigation of Isothermal Treatment on the Structural, Microstructure and Physical Properties of Li2O-Al2O3-SiO2 Glass-Ceramic

2020 ◽  
Author(s):  
Husniyah Aliyah Lutpi ◽  
Hasmaliza Mohamad ◽  
Tuti Katrina Abdullah
Keyword(s):  
Grain Size ◽  
Elevated Temperature ◽  
Physical Properties ◽  
Thermal Shock ◽  
Glass Ceramic ◽  
Crystalline Phase ◽  
Sintering Temperature ◽  
Isothermal Treatment ◽  
Crystalline Phases ◽  
Average Grain Size

Abstract The present work aims to investigate the effects of isothermal treatment on the structural, microstructure and physical properties of Li2O-Al2O3-SiO2 glass-ceramic. Sintering temperature plays a major role in producing the desired lithium aluminosilicate (LAS) glass-ceramic crystalline phases. This work also aims to achieve a low thermal expansion coefficient β-spodumene (LiAlSi2O6) crystalline phase with improved density and lower porosity, which can be useful for the applications with thermal shock properties. The LAS glass-ceramic was fabricated by the melt-quenching technique at 1550 °C for 5 h before being isothermally sintered at an elevated temperature of 900 to 1200 °C for 30 min. The evolution of LAS glass-ceramic crystalline phases was identified using differential thermal analysis and the β-spodumene exothermic peak appeared at 999 °C. Based on the X-ray diffraction results, the complete transformation of β-spodumene from high-quartz solid solution (β-quartz) occurred at 1000 °C. However, the sintering temperature did not change the crystalline phase when sintered above 1000 °C, but the lattice parameter of the crystal structure was slightly altered. Moreover, it was observed that the LAS glass-ceramic grain size increased with temperature, whereby the smallest average grain size recorded (0.61 µm) for LAS glass-ceramic sintered at 1100 °C. Meanwhile, the fully densified LAS glass-ceramic at 1100 ° C was measured at 2.47 g/cm3 with 0.52% porosity. The isothermal treatment at elevated temperature indicated that sintering at 1100 °C provided a denser, less porous, and small average grain size which is preferred for thermal shock resistance applications.

Super Soldiers (Part 1)

2014 ◽  
pp. 119-138 ◽  
Author(s):  
Patrick Lin ◽  
Max Mehlman ◽  
Keith Abney ◽  
Jai Galliott
Keyword(s):  
World War Ii ◽  
Human Enhancement ◽  
The United States ◽  
World War ◽  
The Us ◽  
Psychedelic Drugs ◽  
Public Risk ◽  
Technological Developments ◽  
New Type ◽  
Modern Warfare

After World War II, much debate unfolded about the ethical, legal, and social implications of military human enhancement, due in part to Adolf Hitler's war on the “genetically unfit” and the United States military's experimentation with psychedelic drugs such as LSD. Interest in that debate has waxed and waned since the 1940s. However, it would be foolish or perhaps even dangerous to believe that America and its modern allies have abandoned efforts to upgrade service members' bodies and minds to create the “super soldiers” necessary to match the increasing pace of modern warfare and dominate the strengthening militaries of China and North Korea. Slogans such as “be all that you can be and a whole lot more” still reign strong at the US Defense Advanced Research Projects Agency and, according to some military futurists, the so-called “War on Terror” has only proven that military superpowers need a new type of soldier that is independent, network-integrated, and more lethal than ever before. Patterns of public risk perception, military expenditure, and new technological developments suggest that it is now time to re-open or reinvigorate the original debate. The authors' contribution comes in two parts. In this chapter, they provide a brief background to military human enhancement before defining it carefully and exploring the relevant controversies. In the second, they more explicitly examine the relevant legal, operational, and moral challenges posed by these efforts.

The Effect of Low-Angle and High-Angle Grain Boundaries on Elevated Temperature Strength

1994 ◽  
Vol 362 ◽  
Author(s):  
M. E. Kassner
Keyword(s):  
Elevated Temperature ◽  
Mechanical Behavior ◽  
Large Angle ◽  
High Angle ◽  
Elevated Temperature Strength ◽  
Ambient Temperatures ◽  
The Past ◽  
Creep Regime ◽  
New Evidence ◽  
General Opinion

AbstractThe influence of small (subgrain) misorientation interfaces on the mechanical behavior of metals and alloys deforming within the creep regime has been intensively studied over the past several decades. Controversies have existed, but some new experiments suggest, contrary to the general opinion, that low-angle boundaries are not associated with the rate controlling process for plasticity and do not affect strength. The new evidence will be discussed in terms of other established experimental trends. Large-angle boundaries may have a smaller effect on elevated temperature strength than at ambient temperatures and do not appear to dramatically affect elevated temperature strength. Superplastic effects are not addressed.

Fecal Coliform Methods for Examination of Sea Water: Interlaboratory Evaluation of Split Sample Analysis

1978 ◽  
Vol 61 (4) ◽  
pp. 772-778
Author(s):  
John J Miescier ◽  
Virgil E Carr ◽  
John F Musselman ◽  
Santo A Furfari
Keyword(s):  
Elevated Temperature ◽  
Sea Water ◽  
The United States ◽  
Most Probable Number ◽  
Test Procedures ◽  
Probable Number ◽  
E Coli ◽  
Split Sample ◽  
Elevated Temperature Test ◽  
Temperature Test

Abstract An interlaboratory study was conducted to compare the effectiveness of the following 3 multiple-tube fermentation methods for determining the most probable number (MPN) of Escherichia coli in a split artificial sea water sample: ( 1 ) the 72-hr standard methods procedure of the American Public Health Association, (2) a 24-hr elevated-temperature test using A-l medium, and (3) a 24-hr elevated temperature test modified to include an initial 3-hr resuscitation period using A-l medium. The capability of the laboratories to perform the 3 test procedures was also compared. Split sample replicates with low, medium, and high levels of E. coli were examined in 18 laboratories in the United States and Canada. Data indicate that the laboratories performed each test with equal capability, and all 3 procedures were equally effective in enumerating the strain of E. coli used in this investigation. By virtue of its homogeneity and stability, the split sample served as an appropriate specimen for this study and could probably be used as a proficiency test specimen for evaluating laboratory analyst performance in the bacteriological examination of sea water.

Organizational Identity Formation in Alternative Organizations: A Study of Three Benefit Corporations

2019 ◽  
Vol 33 (4) ◽  
pp. 484-511 ◽  
Author(s):  
Irina M. Kopaneva ◽  
George Cheney
Keyword(s):  
Identity Formation ◽  
Organizational Identity ◽  
Profit Maximization ◽  
The United States ◽  
Bottom Line ◽  
Social Mission ◽  
Benefit Corporation ◽  
Benefit Corporations ◽  
Multiple Case ◽  
New Type

The benefit corporation (BC) in the United States is a new type of corporation legally required to generate profit for its shareholders and to pursue public benefit. BCs explicitly work to balance profit maximization and social mission, which is an ongoing challenge for businesses with an expansive view of the bottom line. This multiple case study extends scholarship on identity formation (IF) in nontraditional organizations, such as BCs, by providing empirical evidence of how identities develop in relation to prevailing cultural sentiments. In particular, we demonstrate how BC struggles over organizational identity (OI) reference broader socioeconomic discourses, identify mechanisms through which perceived pressures suppress alternative interpretations of OI at a micro-level of member interaction, and expose tensions between dominant and alternative frames for business enterprise.

scholarly journals Improving Elevated-Temperature Strength of an Al–Mn–Si Alloy by Strain-Induced Precipitation

Metals ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 446 ◽  
Author(s):  
Yangyang Zhang ◽  
Wei Jin ◽  
Xuanzhang Hao ◽  
Feng Qiu ◽  
Qinglong Zhao
Keyword(s):  
Elevated Temperature ◽  
Elevated Temperature Strength
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