Method for preparation of aluminum matrix composite

Abstract

Disclosed is a method for preparation of an aluminum matrix composite including preparation of in-situ reaction mixed salt, preparation of a TiB2 enhanced 6061 aluminum matrix composite and ultrasonic treatment of a composite melt. The obtained composite contains TiB2 enhancing particles which are fine in size and uniform in distribution and may remarkably improve the mechanical performance indicators of a matrix alloy. In the TiB2 enhanced 6061 aluminum matrix composite according to the present disclosure, the size of the TiB2 enhancing particles is 200-500 nm and the particles are uniform in distribution in the matrix alloy.

What is claimed is: 
     
         1 . A method for preparation of an aluminum matrix composite, where in the method comprises the following steps:
 S 1 , evenly mixing a reaction salt KBF 4  powder, a reaction salt K 2 TiF 6  powder and a reaction auxiliary Na 3 AlF 6  powder in a V-type mixer;   S 2 , drying the powder mixed in the step S 1 ;   S 3 , putting commercial purity aluminum in a resistant furnace, heating and melting the commercial purity aluminum and overheating to 800-810° C.;   S 4 , upon stripping off oxide scale on the surface of the melt, evenly scattering the mixed powder in the step S 2  onto the surface of the melt by a powder sprayer, melting the mixed powder to form a flux layer that floats on the surface of the melt, controlling reaction temperature, and maintaining the temperature for a certain period;   S 5 , upon stripping off reaction salt residues on the surface, performing mechanical agitation on the melt;   S 6 , sequentially adding alloys of Si, Cu, Cr, Mn, Ti, Zn and Mg, and maintaining the temperature for a certain period to completely melt the elements of the alloys;   S 7 , evenly scattering a slag-cleaning agent onto the surface of the melt by a powder sprayer, introducing high-purity argon with a flow rate of 3 L/h, performing mechanical agitation, stirring and degassing for a certain period, and then stripping off scum on the surface;   S 8 , performing ultrasonic treatment on the melt in the step S 7  at an ultrasonic frequency for a certain period; and   S 9 , pouring the melt into a metal mold.   
     
     
         2 . The method for preparation of the aluminum matrix composite according to  claim 1 , wherein in the step S2, the mixed powder is dried at 200-250° C. for 2-3 h. 
     
     
         3 . The method for preparation of the aluminum matrix composite according to  claim 1 , wherein in the step S 1 , an atomic ratio of Ti to B in the K 2 TiF 6  powder and the KBF 4  powder is preferably 1:2, and an addition amount of the reaction auxiliary Na 3 AlF 6  powder is 10-20% of the total mass of the reaction salt K 2 TiF 6  and the reaction salt KBF 4 . 
     
     
         4 . The method for preparation of the aluminum matrix composite according to  claim 1 , wherein in the step S 4 , the reaction temperature is maintained in the range of 830-850° C. for 30-60 min. 
     
     
         5 . The method for preparation of the aluminum matrix composite according to  claim 1 , wherein in the step S 5 , the speed of the mechanical agitation is 250-350 r/min, and the time for the mechanical agitation is 3-5 min 
     
     
         6 . The method for preparation of the aluminum matrix composite according to  claim 1 , wherein in the step S 6 , the elements Si, Cr and Mn are respectively added in the form of intermediate alloys AlSi20, AlCr10, AlMn10 and AlTi20, the elements Cu, Zn and Mg are added in the form of pure metals, and the temperature is maintained in the range of 730-750° C. 
     
     
         7 . The method for preparation of the aluminum matrix composite according to  claim 1 , wherein in the step S 7 , the speed of the mechanical agitation is 250-350 r/min. 
     
     
         8 . The method for preparation of the aluminum matrix composite according to  claim 1 , wherein in the step S 9 , the pouring temperature is in the range of 705-710° C. 
     
     
         9 . The method for preparation of the aluminum matrix composite according to  claim 1 , wherein in the step S 7 , stirring and degassing for 5 min, and in the step S 8 , performing ultrasonic treatment on the melt in the step S 7  at an ultrasonic frequency of 20.1 KHz for 10 min.