Composites from Military Scrap
Utilization of Aircraft and Military Technique Scrap Based on Mechanical Alloying Technology for Producing Heat-Resistant Components
Tech Area / Field
3 Approved without Funding
MISIS (Steel and Alloys), Russia, Moscow
- Voronezh Aircraft Joint Stock Company (VASO), Russia, Voronezh reg., Voronezh\nVNIIKhT (Chemical Technology), Russia, Moscow\nIlyushin Aircraft Association, Russia, Moscow
- Sigma Prime, LLC, USA, MA, Holliston\nTU Delft, The Netherlands, Delft\nUniversity of Tokyo / Research Center for Advanced Science and Technology, Japan, Tokyo
Project summaryIntroduction and reserve.
Composite materials with ceramic particles produced by mechanical alloying show promise for work at elevated temperatures. Such materials strengthened by ceramic dispersoids (CDSM) are usually obtained by combined milling of matrix and ceramic powders (Al2O3, SiC, etc.) in high-energy mills. Strengthening particles can also be synthesized from powder and atmospheric components by combined milling of these components. However, mechanical alloying can also be of interest from different point of view, which, in our view, has still not received proper attention.
Our goal with this Project is to employ mechanical alloying for producing a new class of aluminum-base composite materials. As a secondary raw base material for producing new materials, we propose to use preliminarily comminuted, low-grade, oxidized and mixed aircraft and military scrap, as well as waste of civil machine-building production, for example, lathe or cutting chip. Strong impact-attrition effects in the process of mechanical alloying are supposed to reduce secondary phases of a multicomponent matrix, including intermetallic compounds of impurity origin and oxide inclusions, to nanocrystalline sizes or to dissolve them partly in the aluminum solid solution. It is also expected that dispersed ceramic particles, preliminarily entered and/or synthesized in the process of mechanical alloying, will be uniformly distributed in the matrix. Subsequent specified consolidation and/or plastic deformation of powder granules will make it possible to obtain semi-products with improved properties, in particular, with high heat resistance up to temperatures of 400-450 °C.
The fulfillment of the formulated problem will enable one not only to recycle efficiently low-grade scrap or waste, which is often difficult to process, but also turn its drawbacks - the impurity-contaminated and oxidized surface - into certain advantages. Preliminary laboratory investigations have shown that these tasks can be successfully solved. Two types of composite materials based on a commercial casting multicomponent Al-12%Si-1%Cu-1%Mg-1%Ni (AK12MMgN) alloy, which is destined for producing pistons of internal combustion engines, have been obtained. From a used piston of a truck we produced chip on a lathe. The material of the first type was obtained by combined milling, in an argon atmosphere, of chip and powder of Al2O3 with a volume fraction of 10 to 20% and an initial dispersity of 10 mm. The second material was obtained by processing chip in mills in an air medium to synthesize aluminum and magnesium oxides. Both materials showed high mechanical properties, which greatly exceed the properties of the original matrix alloy.
Program of work and expected results:
1. Analysis of the literary data on secondary metallurgy of aluminum alloys.
2. Analysis of the nomenclature of aircraft and military technical scrap, as well as preliminary selection of types and compositions of scrap for mechanical alloying.
3. Preparation, in high-energy mills, of model powder mixtures from Al-Cu, Al-Cu-Mg, Al-Zn-Mg-Cu, and Al-Si-Cu-Mg-Fe-Ni alloys for a wide range of compositions. Processing will be accomplished (i) in combination with ceramic particles (Al2O3, SiC, and others) in an inert atmosphere and (ii) in an oxidizing medium without preliminary introduction of particles.
4. Investigation of the effect of composition and preliminary structure of matrix alloys, as well as the structure, composition, and volume fraction of strengthening ceramic particles, on the structure of granules of composite materials formed in high-energy mills. This part of work suggests the construction of models that describes the effect of various parameters of the initial structure of the components and of the length of processing in a mill on the structure and properties of granules.
5. Preparation of consolidated laboratory samples under various conditions and investigation of the influence of temperature, pressure, and length of consolidation treatment on the structure. The assessment of basic mechanical and physical properties of materials.
6. Preparation of model and real powder mixtures from compositionally heterogeneous and oxidized raw materials. Analysis of the redistribution of alloying components caused by the mixing of heterogeneous aluminum solid solutions and second phases that entered the mixture from alloys of various compositions. As a consequence, recommendations will be given as to choose the compositions of starting powder mixtures.
7. Development of methods for preparing perse oxidized raw materials for producing CDSM by mechanical alloying. This part of work calls for optimization of technology of preparation of initial heterogeneous charge materials with respect to their dispersity and the level of refining from metallic and nonmetallic impurities.
8. Investigation of thermal stability of the structure and properties of composite materials.
9. Investigation of service characteristics, including heat and wear resistance. Elucidation of strengthening mechanisms at low and high temperatures.
10. Development of technology for obtaining deformed semi-finished products from new composite materials.
11. Production of experimental batch of deformed semi-finished products from new composite materials.
Project manager: Professor V.K. Portnoy, a specialist in the field of physical metallurgy of nonferrous alloys, superplasticity and composite materials, the author of more than 150 scientific publications.
Principal Researcher: A.A. Aksenov, PhD, a specialist in the area of physical metallurgy of nonferrous alloys and composite materials based on these alloys, the author of more than 70 scientific publications.
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