Process for obtaining a low silicon aluminium alloy part

Abstract

The part made of low-silicon aluminum alloy contains magnesium, copper, manganese, titanium, and strontium. Said part is obtained by a method that consists in: casting said alloy in a mold so as to obtain the part; after the casting, demolding the part constituting a preform that is still hot; cooling said preform and then subjecting it to an operation suitable for reheating it to a temperature lying in the range 470° C. to 550° C.; positioning said part between two shells of a die that defines a cavity of dimensions substantially equal to but less than the dimensions of the cavity of the mold; and strongly pressing the two shells together to exert on the part disposed between said shells a combined pressing and surface kneading effect.

1 . A method of obtaining a part made of low-silicon aluminum alloy, containing the alloy comprising:
 silicon at a content lying in the range of 0.5% to 3%;   magnesium at a content lying in the range of 0.65% to 1%;   copper at a content lying in the range of 0.20% to 0.40%;   manganese at a content lying in the range of 0.15% to 0.25%;   titanium at a content lying in the range of 0.10% to 0.20%; and   strontium at a content lying in the range of 0 ppm to 120 ppm; said method including:   casting said alloy in a mold so as to obtain the part;   after the casting, demolding the part constituting a preform that is still hot;   cooling said preform and then subjecting said preform to an operation adapted for reheating saisd preform to a temperature lying in the range of 470° C. to 550° C.;   positioning said part between two shells of a die that defines a cavity of dimensions substantially equal to but less than the dimensions of the cavity of the mold; and   strongly pressing the two shells together to exert on the part disposed between said shells a combined effect of pressing and surface kneading.   
     
     
         2 . An automobile part comprising the Use of a part obtained by the method according to  claim 1 . 
     
     
         3 . An aviation part comprising the part obtained by the method according to  claim 1 .