Authors: V.V. Vikulin, M. Yu. Rusin, L.N. Rusanova
Abstract: A new technology has been developed for making refractory products based on the
naturally occurring wollastonite (calcium metasilicate) intended for the aluminum industry.
The application of natural wollastonite requires no hydrothermal treatment in an autoclave,
which considerably simplifies the manufacturing process and reduces its cost. A qualitative
comparative analysis of natural wollastonite from different mineral deposits was made to
choose an optimal modification with consideration for its availability. The articles were made
by using steel-mold pressing, slip casting and vacuum forming methods. For the development
of technology for manufacturing large-sized complex-shaped products the slip casting method
was used and the slip basic composition was determined comprising 80% of wollastonite as a
basic solid phase and 20% of plasticizers. The improvement in the thermal resistance of
wollastonite-based ceramics is assured by applying special techniques, namely by addition of
course-grained fillers. Thus, addition of about 15% of a course-grained fraction into the fine
wollastonite-based slip improves the thermal resistance of ceramics and affords 2-3 times
increase in their service life. The efficient way to increase the wollastonite-based ceramics
thermal resistance is addition of inorganic fibers. With the use of an inorganic fiber, the
materials have been produced with an apparent density ranging from 0.5 to 1.5 g/cm3 and an
ultimate compressive strength of 0.5 to 10 MPa. The study has been made into ceramics
structure comprising inorganic fibers. The developed materials are chemically inert to
aluminum melt. They show no sticking, no mechanical erosion and they are thermal-resistant.
With the above methods, the following products are being made on the basis of the naturally
occurring wollastonite: spouts, lining plates, heat nozzles, stopper-rod devices, pipes and other
articles that have been operating successfully in the aluminum industry of Russia.
2272
Authors: Rodrigo Estevam Coelho, Paulo Jesus Costa Esteves, Jorge Ferreira Brito
Abstract: Recycle aluminum cans, an alternative route is presented in this work. The aluminum
cans are cut in little flakes with a shears, and then the materials were milled, obtained fine powders.
The weight ratio of the balls to powder was 10 to 1. Equipment of a horizontal high energy ball mill
was utilized. The powder mixture was processed during 0.5, 1 and 2 hours at 950 rpm and after
milling, the powders were directly hot extrusion. The extruder bars were submitted at a tensile tests
and samples microstructures were analyzed by optical microscope. Experimental results obtained
shows that the technique utilized in this work is very important for economized routes and
consequently, less expensive, as compared with conventional methods.
212
Authors: Xing Hua Liang, Xiao Hua Jie
Abstract: The microstructure and properties of brazing weld of 3003 Aluminum Alloy has been studied by using the methods of microstructure observation(SEM), and mechanical-ability was tested. The results showed that the tensile strength reaches 146.2MPa which is close to that of the parent metal. The metallographic structure is α(Al) and α(Al)+Si eutectic structure. The metallographic structure affect the tensile strength and rigidity of the weld joint.
3098
Authors: Fatahul Arifin, Iskandar, Azharuddin Azharuddin
Abstract: Fly ash is waste of coal combustion which can be used in Aluminum alloy. In this research Aluminum is mixed with fly ash that used powder metallurgy method. Aluminum powder is produced by Merck German which is in irregular form and has homogeneous particles, while fly ash is got from residual combustion coal in forging section of Politeknik Negeri Sriwijaya (Polsri) mechanical workshop which is processed until grains size 140 and 270 mesh. Aluminum Powder had mixed with weight fraction 5 % of fly ash for an hour then is pressed with holding time 60 and 120 seconds, compacting pressure are 139 N/mm2 and 275 N/mm2 using cold iso-static pressing. After that green body is resulted then is being sintered until 5500C. Taguchi Method orthogonal L4 is used to find out factors which influence optimum condition of Brinell’s hardness Aluminum/5% fly ash. The result of analysis using ANOVA is grains size factor, holding time, and compacting pressure has affected significantly to hardness of Aluminum/5% fly ash.
284
Authors: Hui Qin Cao, Ji Luo, Wei Wei Yang
Abstract: In order to develop a high-strength aluminum alloy, alumina dispersion strengthened aluminum alloy was prepared by high energy ball milling on 2024 aluminum alloy powder in ethanol. The microstructure, particle size and distribution of the Al2O3 particles in the alloy were analyzed by FE-SEM; the mechanical properties were investigated. Results showed that alumina dispersion strengthened aluminum alloy was prepared successfully by high energy ball milling, the Al2O3 particles of several tens of nm in diameter were homogeneously distributed in the matrix grain and the spatial distance between particles was about 50-100nm. The yield strength and elongation of alumina oxide dispersion strengthened aluminum alloy were 489MPa and 7.9%.
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