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A356 Aluminum Alloy To Strengthen Over The Semi-solid Research To Prepare A Slurry Flow Cooling Method

Posted on:2014-10-30Degree:MasterType:Thesis
Country:ChinaCandidate:Z L JinFull Text:PDF
GTID:2261330401472509Subject:Materials Processing Engineering
Abstract/Summary:PDF Full Text Request
The first, as well as crucial, step of semi-solid processing is to prepare semi-solid slurry. This paper bases on the basis of SSR, combine with chilling and shear centrifugal. Design a new method of nucleation by chilling and centrifugation of cooled club. This technique can be achieved by the cooled club with the ability to produce nucleation, shear centrifugal and the slurry’s since fall type mixing. The author devises a new device by the method of nucleation by chilling and centrifugation of cooled club. The semi-solid slurry of A356aluminium alloy was prepared by the device. The temperature of pouring, the temperature of furnace in the middle of the device, the material of the cooled club, the rotation rate of the cooled club and the time of thermal insulation of slurry were analyzed to the microstructure and grain size of primary a-Al. Author inquires into the mechanism of non-branch crystal’s formation of semi-solid.The liquid state of alloy will come out refinement and spheroidizing mechanism primary a-Al by the way of nucleation by chilling and centrifugation of cooled club. This paper shows that the pouring temperature is low degree of superheat at the exit of the running channel. The low aluminium alloy drains out of the running channel connect with the revolved cooled club. The cooled club makes out large numbers of nucleation from aluminium alloy rapidly. The revolved cooled club centrifugal the aluminium alloy to the face of graphite crucibles which was handed in the middle of the heat insulation furnace. As a result of inertness, gravity and graphite crucibles have a low temperature. Molten aluminium alloy hit each other. The number of crystal nucleus increases more than before. With the same time, the shape of the crystal nucleus changes to more round off.The material of cooled club is stainless steel and fine copper that have same size. Fine copper is just for contrast with stainless steel. Cooled club’s rotating speed decisive the time and area where on the surface of cooled club. Under the others factors are same. Cooled club’s rotating speed is300r/min, the semi-solid primary α-Al are more small, round and homogeneous than other rotating speeds. When the rotating speed is lower than300r/min, the time and area where on the surface of cooled club became more than300r/min. The semi-solid primary a-Al is thickening, not round and couple with the shape of rose. When the rotating speed surpasses300r/min, the time and area where on the surface of cooled club became less than300r/min. But the shearing force is bigger than300r/min. The semi-solid primary a-Al are small and round, however, the second a-Al are thickening, not round and couple with the shape of rose and branch.The heat insulation temperature of slurry is595℃which during the solid line and liquid line. The heat insulation time of slurry is5min or10min. The semi-solid primary a-Al change to more big and round by heat insulation than without heat insulation. The primary a-Al keeps the tendency of growing up. The process of heat insulation of slurry is primary a-Al’s maturation and growth. Primary a-Al’s maturation is chief and growth is secondary when the heat insulation time of slurry is5min. The primary a-Al unites others around it and grows up clearly by10min’s heat insulation time. Consequently, the heat insulation time of slurry can’t be long.The result of A356aluminium alloy of the paper establish the best technique to get the slurry of semi-solid. The pouring temperature is640℃, the temperature of middle thermal insulation, cooled club’s rotating speed is300r/min and the heat insulation time of slurry is5min will obtain primary a-Al are more small, round and homogeneous in the semi-solid.
Keywords/Search Tags:A356Aluminum Alloy, A new method of reinforced inclinedcooling., Semi-solid Slurry, Primary α-Al
PDF Full Text Request
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