Semisolid processing of neareutectic and hypereutectic alsicu alloys. The cup master alloy has no or little modifying effect on eutectic silicon, even though it has obvious modification on primary silicon in the castings. In a hypereutectic solution, there will be a proeutectoid phase of species. Effect of insitu formation of alp on solidification of. As summarized in figure 1, the raw materials approximate 250 g were put in an alumina crucible i. Pdf hypereutectic alsi alloy castings with a completely eutectic. We have passed iso9001 qm system and national military stardard. Hypereutectic alloys are, in reality, insitu metal matrix composites mmc of hard silicon crystals disbursed throughout a eutectic. Microstructure and creep behavior of alsicumgni piston alloys. A hypereutectic piston is an internal combustion engine piston cast using a hypereutectic alloythat is, a metallic alloy which has a composition beyond the eutectic point.
Study of mechanical and wear behaviour of hypereutectic alsi. Structure formation of hypereutectic alsialloys produced. Eis results for hypereutectic alsicu alloys in naturally aerated csas at increasing immersion periods, showing nyquist and b ode phase diagrams for. Spray forming of hypereutectic alsi alloys request pdf. Pdf microstructure and mechanical property of alsi alloy. Microstructure evolution and high density of nanotwinned. The term hyper is rooted in greek, meaning above or over. Properties of eutectic and hypoeutectic alsi alloys. Properties of eutectic and hypoeutectic alsi alloys 1579 water and alcohol and then dried. Decomposition of metastable structures in hypereutectic alsi alloys.
Therefore, hypereutectic alsi alloys are widely used in aeronautic, astronautic, and automobile industries. Hypereutectic alsi alloys and their composites attract much attention for heat dissipation and electronic packaging applications due to their low density, high wear resistance, low thermal expansion coefficient and excellent thermal conductivity 1,2. Review of microstructure evolution in hypereutectic alsi. Thsindi cates that the cup master alloy has stronger modifying ef fect on the hypereutectic alsi alloy at a pouring tempera ture of above 800 after 30 min soaking. Recent work on the solidification of hypereutectic alsi alloys having between 1520% silicon has focused on the solubility of barium in the silicon phase.
It has been documented extensively that the microstructure of hypereutectic alsi alloys, prepared by conventional casting routines, usually consist of a coarse primary silicon phase in a fibrous eutectic matrix 4 6. However, microstructure and xrd showed refinement of the eutectic silicon phase in the lasertreated zone and induced precipitation of silicon in the alrich matrix. For examples, hypereutectic alsi alloys with a uniform distribution of fine primary silicon particles have higher strength and better wear resistance. Eutectic alloys have two or more materials and have a eutectic composition. Al phase, which does not occur in the microstructure of hypereutectic alsi alloys when using traditional alloying methods. Refinement of the cast microstructure of hypereutectic. Corrosion performance of alsicu hypereutectic alloys in a. The invention relates to a method for the heat treatment of a cast part a hypereutectic alsi alloy and a correspondingly manufactured one casting.
Baienwei is a expert manufacture specializing in alluminum silicon alloys production in china. Formation of hypereutectic silicon particles in hypoeutectic alsi. Friction and wear behaviour of hypereutectic alsi alloysteel. Microstructure and mechanical properties of hypohyper. Effect of insitu formation of alp on solidification of hypereutectic alsi alloy. Effect of al5tic master alloy on the microstructure and. Microstructure and mechanical properties of spray formed. Pdf semisolid processing of neareutectic and hypereutectic. When 30 % alsi alloy auto parts, dispal aluminum alloy auto parts, powder metallurgy auto parts, engine parts. Hypereutectic alsi alloy, wear, worn surfaces, sem. Each sample was then observed and photographed at a magnification of x300. Hypereutectic alloys page 1 of 6 now, consider a mixture of a and b so that the overall composition of the alloy places it to the right of the eutectic point. The liquidus and eutectic temperature were evaluated from the cooling curves. Refinement of the cast microstructure of hypereutectic aluminum.
Experiments with electrolytic alsi alloy deasa were conducted to produce the pure eutectic structure without impurityaddition in hypereutectic alloys castings. These alloys are an excellent engine piston material, which is widely used in aerospace, shipbuilding, and the automobile industry, in addition to. Corrosion performance of alsicu hypereutectic alloys in. For castings made of eutectic or hypoeutectic aluminum alloys it has long been known that this can be done through appropriate heat treatment can be cured. Formation of hypereutectic silicon particles in hypoeutectic alsi alloys under the influence of highintensity ultrasonic vibration xiaogang jian1 and qingyou han2 1. Several hypereutectic alsi alloys are in commercial use in. The alumina crucible was put in a resistance heating furnace with a proportionalintegral.
Typical uses of hypereutectic alsi alloys are pistons, cylinder liners, piston rings, connecting rods, pump and hydraulic components. In recent years, these alloys have drawn the attention. Pdf experiments with electrolytic alsi alloy deasa were conducted to produce the pure eutectic structure without impurityaddition in hypereutectic. The alloys were solidified with different cooling rates from different super heat temperatures. This invention relates to a eutectic or hypereutectic aluminiumsilicon alloy product suitable for thixoforming, comprising by weight 10 to 30% silicon and, if applicable, copper hypereutectic alloy increases with the addition of copper. Alsi alloys with silicon content more than % are termed as hypereutectic alloys. The thermal analysis results indicated that the addition of sm in al12si alloy caused a depression of eutectic temperature. Hypereutectic aluminiumsilicon alloys are used in applications that require high resistance to wear, corrosion, good mechanical properties. At the same time, the structure and mechanical properties of hypereutectic unmodi. The authors include a description of the manufacturing principles, thermodynamics, and other main characteristics of al. However, there is a growing interest in hypereutectic alsi alloys for.
When the composition of an alloy places it to the right of the eutectic point it is called hypereutectic. The modification of neareutectic alsi alloy with samarium additions 00. And it was found that sm was capable of breaking down the primary. Formation of hypereutectic silicon particles in hypoeutectic. Microstructure and mechanical property of alsi alloy. A1 phases, giving rise to an increment in the number of dendrites. Hypereutectic aluminumsilicon alsi alloys are widely used in the aerospace and automobile industries because of their low density, excellent wear and corrosion resistance, low coefficient of thermal expansion, good strength, and excellent castability. The compaction, sintering and heat treatment processing conditions for the commercial powder, ecka alumix 231 with the nominal. This book details aluminum alloys with special focus on the aluminum silicon al. When a noneutectic alloy solidifies, its components solidify at different temperatures, exhibiting a plastic melting range.
Microstructure and mechanical properties of hypereutectic alsi. Specifically, it appeared that the electric current changed the size distribution of the primary silicon particles by increasing the population of comparatively smaller size particles, although it did not affect the eutectic silicon particles. Dry and lubricated sliding tribological tests on hypereutectic al25si alloy was performed using a ball on disk configuration at room temperature. Alloy system and properties chemistry and microstructure. Precipitation of primary silicon was studied in alsi hypereutectic alloys with 15, 18, and 25 wt. It has been suggested that corrosion of alsi hypereutectic alloys starts at the matrixprecipitate interface9. In this study, the effect of sc addition on the microstructure and mechanical properties of al20si alloys fabricated by extrusion of powders was investigated. As electronic packaging strives continuously toward smaller size, higher integration and more complex geometries. A method for improving the mechanical properties of a. Development of hypereutectic alsi based pm alloys su, shei sia 2012. The effect of sc on the microstructure and mechanical.
Structure formation of hypereutectic alsialloys produced by. Efficiency of sr modification in hypereutectic alsi alloys manuscript id. The hypereutectic alsi alloy market revenue was xx. Hypereutectic alsi alloy is being used in the automobile industry and in other fields where high wear resistance, high specific stiffness. Hypereutectic alsi alloys are typically defined as those where the silicon content is equal or more than 17 wt %. Friction and wear behaviour of hypereutectic alsi alloy.
Machinability of hypereutectic cast alsi alloys processed by ssm processing technique p k sood1, rakesh sehgal1 and d k dwivedi2 1department of mechanical engineering, national institute of technology, hamirpur 177005, india. Microstructure and mechanical properties of spray formed and. Machinability of hypereutectic cast alsi alloys processed by. Hypereutectic alsi cast alloys are common materials used manufacturing lightweight and wearfor resistant components12. Influence of semisolid compression conditions on the. Microstructure and mechanical properties of hypereutectic. Hypereutectic alsi alloys have excellent properties such as low thermal expansion, high wear resistance, high corrosion resistance, small specific gravity, and good thermal conductivity 1,2. Modification of neareutectic alsi alloys with rare earth. The enlightenments provided in this article should remove some of the aura of mystery surrounding hypereutectic alloys and thus ease the concerns of foundries being offered opportunities to provide product cast from this interesting and useful family of alloys.
Pdf microstructural evolution and mechanical properties. Study on microstructure and mechanical properties of. Machinability of hypereutectic cast alsi alloys processed by ssm processing technique p k sood1, rakesh sehgal1 and d k dwivedi2 1department of mechanical engineering, national institute of technology, hamirpur 177005, india 2department of mechanical and industrial engineering, indian institute of technology, roorkee 247667, india email. Reinforcement of silicon particles improves the hardness, which further enhances the wear resistance property of alsi hypereutectic alloys warmuzek, 2004. In this study attention has been paid towards the microstructure, mechanical and tribological properties of. New approaches to casting hypereutectic alsi alloys to achieve. Hypereutectic alsi alloy microstructure compared to f3s20p metal matrix composite mmc. If the phase diagram had been drawn the other way around, with 100%a on the right and 100%b on the left, then the same alloy would be called hypoeutectic.
Phase evolution during the solidification process of the alloy subjected to ultrasonic vibration is described. Joshi abstractmodified al alloys are gaining emphasis in the past few years due to wide range of properties available for the engineering applications. Hypereutectic pistons are made of an aluminum alloy which has much more silicon present than. It has been proven that modification of eutectic silicon plays an important role in improving the mechanical properties of hypoeutectic alsi alloys. Hypereutectic aluminumsilicon alsi casting alloys have been widely employed in aerospace, automotive and general engineering industries due to their excellent casting and mechanical properties, such as high strength to weight ratio, good corrosion resistance, high wear resistance, low melting point, good thermal conductivity and low thermal expansion coefficient. Pdf alsi alloys with silicon content more than % are termed as hypereutectic alloys. Met department, purdue university, west lafayette, in 47906, usa a luminumsilicon alsi alloys are highly versatile. Structure formation of hypereutectic alsialloys produced by laser surface treatment 391 diffraction patterns from the pdf2 database 2010 showed that samples alsi30, alsi40 and alsi60 are twophase and contain 33, 44 and 67% wt. Data on the structure and mechanical properties of cast alsi alloys in a wide compositional range from hypoto high hypereutectic composition are scares. Hypereutectic alsi alloy with completely nodular eutectic. The properties of the hypereutectic alloy are greatly dependent on the morphology, size and distribution of primary silicon crystals in the alloy. It has also been suggested that the work material deposition occurs when the. Spray forming has been chosen as an efficient way to manufacture aluminum alloys, such as hypereutectic aluminum silicon alloys 2, with enhanced properties due to the rapid solidification, which is very helpful to the generation of the fine, uniform and macrosegregationfree microstructures 14.
Structural and mechanical properties of alsi alloys. Machinability of hypereutectic cast alsi alloys processed. Accepted manuscript performance of different tig remelting. The alsisc powders produced by high pressure gas atomization were used in. On temperatures and tool wear in machining hypereutectic al. Hypereutectic alsi systems such as 390 alloy became popular in the early 1970s in premium german engines and compressors, and grew in popularity in north america for use in pumps, compressors, transmission components, pistons and similar wear applications. Synthesis and characterization of hypoeutectic alsi alloys. Structural and mechanical properties of alsi alloys obtained by fast. Coarse silicon particles give poor mechanical properties.
Study on microstructure and mechanical properties of hypereutectic. Boosting aluminumsilicons strength, ductility in a permanent mold casting. Debinding and sintering of an injectionmoulded hypereutectic. Hypereutectic definition of hypereutectic by the free. Ep1239054a1 heat treatment of hypereutectic alsi alloys. Spray deposition process of hypereutectic alsi alloys. Alsi alloys automotive, aeronautical, and aerospace. Thixoforming of hypereutectic alsi automotive pistons.