The Characterization and Conservation of Aged Aluminum Alloys: Buckminster Fuller's Dymaxion House

2002 ◽  
Vol 712 ◽  
Author(s):  
Karen A. Trentelman ◽  
James Ashby ◽  
William T. Donlon
Keyword(s):  
Aluminum Alloys ◽  
Structural Integrity ◽  
Primary Aluminum ◽  
Grain Structure ◽  
Age Hardening ◽  
Original Structure ◽  
Visual Appearance ◽  
Henry Ford ◽  
Buckminster Fuller ◽  
Cladding Layers

ABSTRACTThe Dymaxion House is a unique historic dwelling structure designed by Buckminster Fuller. Built in the 1940s, the house was constructed of modern materials, most notably aluminum, which formed the walls, roof and many of the structural elements. The challenge faced in reconstructing the Dymaxion House at Henry Ford Museum & Greenfield Village was to preserve the original structure as much as possible while simultaneously accommodating the needs of exhibition (i.e. to restore the visual appearance and ensure sufficient structural integrity to allow the entrance of visitors). The primary aluminum alloys used in the house are equivalent to the modern alloy designations 2014 and 2024; both extruded forms and Alclad sheets were used. The alloy composition, age-hardening characteristics, cladding layers, grain structure and corrosion products of the aged aluminum components of the Dymaxion House have been studied. The results of these studies were used in consultation with conservators, engineers and corrosion scientists to determine the most appropriate course of treatment.

Post-Fire Mechanical Properties and Hardness of 5083 and 6082 Aluminum Alloys

2012 ◽  
Author(s):  
P. T. Summers ◽  
R. D. Matulich ◽  
Scott W. Case ◽  
Brian Lattimer
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloys ◽  
Vickers Hardness ◽  
Structural Integrity ◽  
Elevated Temperatures ◽  
Mechanical Response ◽  
Primary Aluminum ◽  
Fire Exposure ◽  
Passenger Rail ◽  
Structural Applications

Aluminum alloys are being increasingly used in lightweight transportation applications such as naval vessels and passenger rail. The primary aluminum alloys considered are Al-Mg (5xxx) and Al-Mg-Si (6xxx) due to their mechanical strength, corrosion resistance, and weldability. A major concern in the use of aluminum alloys for lightweight structural applications is fire exposure. Aluminum mechanical properties begin to significantly degrade at temperatures above 300°C. After fire exposure, structural integrity will be governed by the residual, post-fire strength of the aluminum. However, scarce data is available regarding the post-fire mechanical response. The post-fire mechanical properties were characterized for several aluminum alloys: 5083-H116, 6082-T651 plate, and 6082-T6 extrusion. The alloys were exposed to elevated temperatures in a furnace to simulate a fire environment. Tension tests were performed to determine the mechanical response of the alloys. Vickers hardness measurements were also performed on specimens exposed for varying durations and temperatures to quantify the time and temperature-dependent behavior. The observed behaviors were explained in relation to the microstructural strengthening mechanisms for each alloy. Correlations were developed between the mechanical properties and Vickers hardness indentations.

Strong and ductile age-hardening Mg-Al-Ca-Mn alloy that can be extruded as fast as aluminum alloys

2017 ◽  
Vol 130 ◽  
pp. 261-270 ◽  
Author(s):  
T. Nakata ◽  
C. Xu ◽  
R. Ajima ◽  
K. Shimizu ◽  
S. Hanaki ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Age Hardening

FEASIBILITY STUDY ON JOINING DISSIMILAR ALUMINUM ALLOYS AA6061 AND AA7075 BY TUNGSTEN INERT GAS (TIG)

2015 ◽  
Vol 75 (7) ◽  
Author(s):  
Mahadzir Ishak ◽  
Nur Fakhriah Mohd Noordin ◽  
Luqman Hakim Ahmad Shah
Keyword(s):  
Aluminum Alloys ◽  
Butt Joint ◽  
Tig Welding ◽  
Inert Gas ◽  
Depth Of Penetration ◽  
Visual Appearance ◽  
Melted Zone ◽  
Dissimilar Aluminum Alloys ◽  
Aa 7075 ◽  
Filler Metals

The aim of this paper is to study the feasibility of welding dissimilar aluminum alloys AA6061 and AA7075 using different types of filler metals which are ER4043 and ER5356. The tungsten inert gas (TIG) welding method was used to butt joint these alloys. The effect of ER4043 (Si-rich) and ER5356 (Mg-rich) on weldability of the joint were studied through visual appearance, microstructures and hardness. It was found that, welding using filler ER5356 produced deeper penetration compared to filler ER4043. The depth of penetration obtained using filler ER5356 was 1.74 mm, while only 0.9 mm of penetration was obtained using ER4043. Microstructures at different zones of dissimilar TIG joints such as the fusion zone (FZ), the partially melted zone (PMZ) and the heat affected zone (HAZ) were identified. The grain size at FZ from filler ER5356 samples was finer compared to filler ER4043 which was 11.4 µm and 19.5 µm, respectively. The average hardness welding value of filler ER5356 samples was higher compared to filler ER4043 samples, which were 100HV and 86HV, respectively at HAZ of AA 6061, 110HV and 88HV, respectively at FZ, while 113HV and 85HV, respectively at HAZ of AA 7075. It can be concluded that TIG welding using the ER5356 filler yields better joint compared to ER4043.

Innovative Upgrading of Heritage Buildings: Structural Case Studies

2018 ◽  
Author(s):  
Kribanandan Gurusamy Naidu
Keyword(s):  
Case Studies ◽  
Structural Integrity ◽  
Adaptive Reuse ◽  
Urban Spaces ◽  
Masonry Buildings ◽  
Fair Share ◽  
Visual Appearance ◽  
Heritage Buildings ◽  
Proper Design ◽  
Structural Case

<p>The challenge of integrating old and new in the development of urban spaces is constrained by commercial realities and an ignorance of the value of maintaining historical relevance as society develops. Malaysia has had its fair share of such historical gems being destroyed without much consideration for heritage but there also exists significant projects where proper design and engineering have been applied for conservation and adaptive reuse.</p><p>In this paper innovative options for structural upgrading of masonry buildings is considered using techniques which provide a basis for achieving structural integrity without compromising the visual appearance and historical value. This includes examples of a shop house upgraded following significant settlement due to adjacent construction and an adaptive reuse of a school which was converted into a theatre.</p>

scholarly journals Recent advances in the metallurgy of aluminum alloys. Part II: Age hardening

2018 ◽  
Vol 19 (8) ◽  
pp. 688-709 ◽  
Author(s):  
Christophe Sigli ◽  
Frédéric De Geuser ◽  
Alexis Deschamps ◽  
Joël Lépinoux ◽  
Michel Perez
Keyword(s):  
Aluminum Alloys ◽  
Age Hardening ◽  
Recent Advances

Retrogression and Re-aging Heat Treatment: AA7XXX Aluminum Alloys

2019 ◽  
Author(s):  
V. Anil Kumar ◽  
S. Arjun ◽  
R.K. Gupta ◽  
P.V. Venkitakrishnan
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloys ◽  
Industrial Applications ◽  
Age Hardening ◽  
Large Cross Section ◽  
Structural Applications ◽  
The Matrix ◽  
Peak Aged ◽  
Aged Temper ◽  
Short Time

Retrogression and re-aging (RRA) treatment was introduced to increase the stress corrosion cracking (SCC) resistance while retaining the strength attainable in T6 (peak aged) temper. Retrogression is a short-term heat treatment at an elevated temperature wherein a partial dissolution of metastable precipitates occurs, which are responsible for the hardening. During the next step, the material is re-aged in the regime of typical age hardening parameters to restore the strength with improved ductility. Response of RRA treatment has been reported on AA7XXX series Aluminum alloys such as AA7075, AA7050, AA7150, AA7049, and AA7010. Studies have been done on the effect of RRA on microstructure, mechanical properties such as tensile and hardness, corrosion, exfoliation corrosion, and SCC resistance by various researchers. The key characteristic of RRA is retrogression, which makes the re-precipitation in the matrix and coarsening of grain boundary precipitates such as MgZn2, η′. The retrogression treatment however requires high temperature and a short time, which limits the industrial application of RRA, especially in the heat treatment of the components with large cross section, due to the inherent thermal conductivity limitations. Hence, further work needs to be done in this area to apply this specialized heat treatment for industrial applications. This article brings out a comprehension of the changes in microstructure, tensile properties, and corrosion resistance of the various commonly used AA7XXX Aluminum alloys in structural applications with RRA heat treatment. The future scope of the work in RRA heat treatment is also discussed in this article.

Three Strategies to Achieve Concurrent Strengthening by Ultrafine-Grained and Precipitation Hardenings for Severely Deformed Age-Hardnable Aluminum Alloys

2016 ◽  
Vol 1135 ◽  
pp. 161-166 ◽  
Author(s):  
Shoichi Hirosawa ◽  
Yong Peng Tang ◽  
Zenji Horita ◽  
Seung Won Lee ◽  
Kenji Matsuda ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Equivalent Strain ◽  
Age Hardening ◽  
Cu Alloy ◽  
Ultrafine Grained ◽  
Δ Phase ◽  
Microalloying Elements ◽  
Wrought Aluminum Alloys

In this paper, comprehensive studies on the age-hardening behavior and precipitate microstructures of severely deformed and then artificially aged aluminum alloys have been conducted to clarify whether or not concurrent strengthening by ultrafine-grained and precipitation hardenings can be achieved. From our graphically-illustrated equivalent strain dependence of both the attained hardness and increment/decrement in hardness during aging (i.e. age-hardenability), three strategies to maximize the combined processing of severe plastic deformation and age-hardening technique are proposed. (1) Lowering of aging temperature and (2) utilization of microalloying elements can improve not only the attained hardness but also the age-hardenability of high-pressure torsion (HPT) specimens of Al-Mg-Si (-Cu) alloy due to the increased volume fraction of transgranular precipitates. A further increase in hardness can be achieved by (3) taking advantage of spinodal decomposition for HPTed Al-Li-Cu alloy, in which nanoscale precipitates of δ’ phase are successfully formed within ultrafine grains, irrespective of the higher number density of grain boundaries. The attained hardness of >HV290 in the latter alloy is almost the highest among conventional wrought aluminum alloys, and therefore our proposed strategies will be useful for designing concurrently strengthened severely-deformed age-hardenable aluminum alloys.

scholarly journals Aesthetics and Gloss of Ground Surfaces: A Review on Measurement and Generation

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Barbara Linke ◽  
Jayanti Das
Keyword(s):  
Chemical Properties ◽  
Perceived Quality ◽  
Optical Quality ◽  
Grain Structure ◽  
Surface Generation ◽  
Free Form ◽  
Surface Appearance ◽  
Visual Appearance ◽  
Geometrical Properties ◽  
Free Form Surfaces

Visual appearance of an object significantly influences a consumer's choice and largely controls the market economy. The perceived quality of products is governed by surface's optical properties (reflection, refraction, etc.), geometrical properties (roughness, waviness, etc.), and chemical properties (oxide layer formation, thermal variation, etc.). Surface shininess attracts researchers from many different disciplines, in particular manufacturing, metrology, psychology, physiology, and computer science. Unfortunately, there are still huge knowledge gaps on characterizing and appraising shiny surfaces in a reproducible way. This paper introduces the main definitions and physics of shininess and gloss, methods of gloss sensing, and relates these definitions and methods to surface generation by grinding. Automated gloss measurement is difficult in particular for free-form surfaces, and optical quality is still often evaluated by human workers. Gloss models are often based on the bidirectional reflection distribution function (BRDF) of the surface, but the models are commonly not connected with the manufacturing process. This study proposes to consider the geometrical features (defects, waviness, lay, and roughness) of metal surfaces as well as the physical and chemical features (grain structure and microlayers) to understand surface appearance and manufacturing in a holistic way. Preliminary tests show that 2D roughness measurements are not connected well with measured gloss units (GUs) and subjective, perceived quality. More fundamental research on the generation and measurement of surface appearance is needed and would benefit many industries.

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