Aluminium-titanium-niobium-boron intermediate alloy and preparation method and application thereof

Abstract

A preparation method of an Al—Ti—Nb—B intermediate alloy includes following steps. KBF4 powder, Nb powder, and Ti powder are ball milled to obtain mixed powder, the mixed powder is pressed to obtain a ball-milled block, an Al block is melted to obtain an Al melt, the ball-milled block is added to the Al melt followed by smelting to obtain alloy liquid, and the alloy liquid is cast to obtain the Al—Ti—Nb—B intermediate alloy as a refining agent. A high-energy ball milling process is introduced into the preparation method of the Al—Ti—Nb—B intermediate alloy, improving reaction activity and lowering a reaction threshold. An α-Al grain can be refined to be less than 90 μm due to uniform dispersion of refining nucleation particles of the refining agent, the refining agent has a great refining effect. The preparation method is simple with easy steps and operations, the Al—Ti—Nb—B intermediate alloy has high purity.

The invention claimed is: 
     
         1 . A preparation method of an aluminium (Al)-titanium (Ti)-niobium (Nb)-boron (B) intermediate alloy, comprising:
 ball milling potassium tetrafluoroborate (KBF 4 ) powder, Nb powder, and Ti powder to obtain mixed powder; pressing the mixed powder to obtain a ball-milled block; melting an Al block at 750-800 degree Celsius (° C.) to obtain an Al melt; adding the ball-milled block to the Al melt followed by smelting to obtain alloy liquid; and casting the alloy liquid to obtain the Al—Ti—Nb—B intermediate alloy;   wherein a particle size of the Nb powder is in a range of 30 micrometers (m) to 50 μm, and a particle size of the Ti powder is in a range of 1 μm to 50 μm;   wherein a rotation speed in the ball milling is in a range of 200 revolutions per minute (r/min) to 300 r/min, and time of the ball milling is in a range of 4 hours (h) to 6 h;   wherein a temperature of the smelting is in a range of 750° C. to 800° C., and time of the smelting is in a range of 20 minutes (min) to 60 min;   wherein the Al—Ti—Nb—B intermediate alloy comprises the following compositions in percentage by weight: Al: 94.9%-96.7%, Ti: 0.5%-1.5%, Nb: 2.5%-4%, B: 0.3%-0.8%; and   wherein the Al—Ti—Nb—B intermediate alloy comprises refined nucleating phases, the refined nucleating phases are (Nb/Ti)Al 3  and (Nb/Ti)B 2 , a weight percentage of the refined nucleating phases in the Al—Ti—Nb—B intermediate alloy is in a range of 1% to 6%, a particle size of the refined nucleating phases is in a range from 1 m to 80 μm, and a particle size of the (Nb/Ti)B 2  is not greater than 5 μm.   
     
     
         2 . The preparation method of the Al—Ti—Nb—B intermediate alloy as claimed in  claim 1 , wherein the ball milling is wet milling, a milling medium is anhydrous ethanol, and a ball-to-material ratio is in a range of 5 to 15:1. 
     
     
         3 . The preparation method of the Al—Ti—Nb—B intermediate alloy as claimed in  claim 1 , wherein the adding the ball-milled block to the Al melt comprises:
 adding the ball-milled block wrapped in Al foil to the Al melt. 
 
     
     
         4 . The preparation method of the Al—Ti—Nb—B intermediate alloy as claimed in  claim 1 , wherein the smelting comprises: stirring the ball-milled block and the Al melt for 0.5-1 min each time at time intervals of 10-20 min. 
     
     
         5 - 6 . (canceled)