Recent developments in advanced aircraft aluminium alloys
TL;DR: In this paper, the authors cover the latest developments in enhanced mechanical properties of aluminium alloys, and high performance joining techniques, including laser beam welding and friction stir welding, and compare them with the traditional aluminum alloys.
About: This article is published in Materials & Design.The article was published on 2014-04-01. It has received 1726 citations till now. The article focuses on the topics: 5005 aluminium alloy & Aluminium.
Citations
More filters
TL;DR: A simple and effective strategy to transform bulk natural wood directly into a high-performance structural material with a more than tenfold increase in strength, toughness and ballistic resistance and with greater dimensional stability is reported.
Abstract: Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example, polymer-based and biomimetic composites) Natural wood is a low-cost and abundant material and has been used for millennia as a structural material for building and furniture construction However, the mechanical performance of natural wood (its strength and toughness) is unsatisfactory for many advanced engineering structures and applications Pre-treatment with steam, heat, ammonia or cold rolling followed by densification has led to the enhanced mechanical performance of natural wood However, the existing methods result in incomplete densification and lack dimensional stability, particularly in response to humid environments, and wood treated in these ways can expand and weaken Here we report a simple and effective strategy to transform bulk natural wood directly into a high-performance structural material with a more than tenfold increase in strength, toughness and ballistic resistance and with greater dimensional stability Our two-step process involves the partial removal of lignin and hemicellulose from the natural wood via a boiling process in an aqueous mixture of NaOH and Na2SO3 followed by hot-pressing, leading to the total collapse of cell walls and the complete densification of the natural wood with highly aligned cellulose nanofibres This strategy is shown to be universally effective for various species of wood Our processed wood has a specific strength higher than that of most structural metals and alloys, making it a low-cost, high-performance, lightweight alternative
830 citations
TL;DR: By a process of complete delignification and densification of wood, a structural material with a mechanical strength of 404.3 megapascals is developed, more than eight times that of natural wood, resulting in continuous subambient cooling during both day and night.
Abstract: Reducing human reliance on energy-inefficient cooling methods such as air conditioning would have a large impact on the global energy landscape. By a process of complete delignification and densification of wood, we developed a structural material with a mechanical strength of 404.3 megapascals, more than eight times that of natural wood. The cellulose nanofibers in our engineered material backscatter solar radiation and emit strongly in mid-infrared wavelengths, resulting in continuous subambient cooling during both day and night. We model the potential impact of our cooling wood and find energy savings between 20 and 60%, which is most pronounced in hot and dry climates.
710 citations
TL;DR: It is shown that an FeAl-type brittle but hard intermetallic compound (B2) can be effectively used as a strengthening second phase in high-aluminium low-density steel, while alleviating its harmful effect on ductility by controlling its morphology and dispersion.
Abstract: Although steel has been the workhorse of the automotive industry since the 1920s, the share by weight of steel and iron in an average light vehicle is now gradually decreasing, from 68.1 per cent in 1995 to 60.1 per cent in 2011 (refs 1, 2). This has been driven by the low strength-to-weight ratio (specific strength) of iron and steel, and the desire to improve such mechanical properties with other materials. Recently, high-aluminium low-density steels have been actively studied as a means of increasing the specific strength of an alloy by reducing its density. But with increasing aluminium content a problem is encountered: brittle intermetallic compounds can form in the resulting alloys, leading to poor ductility. Here we show that an FeAl-type brittle but hard intermetallic compound (B2) can be effectively used as a strengthening second phase in high-aluminium low-density steel, while alleviating its harmful effect on ductility by controlling its morphology and dispersion. The specific tensile strength and ductility of the developed steel improve on those of the lightest and strongest metallic materials known, titanium alloys. We found that alloying of nickel catalyses the precipitation of nanometre-sized B2 particles in the face-centred cubic matrix of high-aluminium low-density steel during heat treatment of cold-rolled sheet steel. Our results demonstrate how intermetallic compounds can be harnessed in the alloy design of lightweight steels for structural applications and others.
486 citations
TL;DR: In this paper, the authors focus on the following topics: (1) materials requirements in design of aircraft structures and engines, (2) recent advances in the development of aerospace materials, (3) challenges faced by recent aerospace materials and (4) future trends in aerospace materials.
477 citations
TL;DR: In this paper, the development history and applications of Al-Li alloys over the last few years are reviewed, and the main issue of anisotropic behavior of all the alloys is discussed.
360 citations
Cites background or methods from "Recent developments in advanced air..."
...33 0 years without a single documented fracture (crack or corrosion issues) [3,8]....
[...]
...However, Fe, Si, Na, and K have negative influence on AlLi alloys [3,8]....
[...]
...Additionally, using 2060-T8 for fuselage skin and lower wing structures instead of AA2524-T3 and 2024-T351 may save 7% and 14%, respectively [8,65]....
[...]
...This was attributed to their superior mechanical and physical properties compared with other alloys [8,65]....
[...]
...In the early 1990s, 3 generation Al-Li alloys were introduced to the market, and these alloys featured a reduced Li concentration (Li < 2 wt%) to overcome the previously mentioned limitations of former Al-Li alloys [3,8,65]....
[...]
References
More filters
TL;DR: In this article, the authors deal with the fundamental understanding of the process and its metallurgical consequences, focusing on heat generation, heat transfer and plastic flow during welding, elements of tool design, understanding defect formation and the structure and properties of the welded materials.
1,811 citations
TL;DR: The focus of this paper is aircraft and aircraft engines but the broader focus is on the role of materials in creating lightweight structures, and there are examples used that are relevant to automotive applications once they are adjusted for cost.
1,746 citations
TL;DR: Aluminum alloys have been the primary material of choice for structural components of aircraft since about 1930 as discussed by the authors and have been used extensively in high-performance military aircraft and are being specified for some applications in modern commercial aircraft, including the fuselage, wing, and supporting structure of commercial airliners and military cargo and transport.
1,077 citations
TL;DR: A technical review of the physical, mechanical, and metallurgical variables that have influenced performance of Al-Li based alloys over the last 50 years is presented in this article.
Abstract: A technical review of the physical, mechanical, and metallurgical variables that have influenced performance of Al-Li based alloys over the last 50 years is presented. First, the historic evolution of different alloys is discussed. Then, the microstructural features responsible for different mechanical properties are identified and discussed. The role of alloying additions is discussed. The shortcomings of a 2nd generation Al-Li alloys are introduced and the key alloy design principles used to overcome these are discussed. Finally, the performance parameters that play a major role in sizing several aircraft and space craft components are reviewed in a chronological perspective and compared with 3rd-generation Al–Li alloys. It is concluded that significant improvements have been made to position Al–Li alloys to enable improved performance of next generation of air and space craft.
715 citations
TL;DR: In this article, the combination of these aspects in one material is an extraordinary achievement, and it shows that GLARE is a unique material for aircraft applications, and that it is a strong candidate material for fuselage skin structures of the new generation of aircraft.
542 citations