Aluminum-zirconium-titanium-carbon grain refiner and method for producing the same

Abstract

The present invention pertains to the field of metal alloy, and discloses an aluminum-zirconium-titanium-carbon grain refiner for magnesium and magnesium alloys, having a chemical composition of: 0.01%10% Zr, 0.01%10% Ti, 0.01%0.3% C, and Al in balance, based on weight percentage. Also, the present invention discloses the method for preparing the grain refiner. The grain refiner according to the present invention is an AlZrTiC intermediate alloy having great nucleation ability and in turn excellent grain refining performance for magnesium and magnesium alloys, and is industrially applicable in the casting and rolling of magnesium and magnesium alloy profiles, enabling the wide use of magnesium in industries.

Claims

1. A method comprising the steps of: a. melting commercially pure aluminum, heating to a temperature of 1000-1300 Celsius, and adding zirconium, titanium and graphite powder thereto to be dissolved therein, and b. keeping the temperature under agitation for 15-20 minutes, and performing casting molding to obtain an aluminum-zirconium-titanium-carbon (AlZrTiC) intermediate alloy having dispersed ZrC and Al.sub.4C.sub.3 mass points and a chemical composition consisting of: 0.01%10% Zr, 0.01%10% Ti, 0.01%0.3% C, and Al in balance, based on weight percentage.

2. A method comprising the steps of: a. melting commercially pure aluminum, heating to a temperature of 1000-1300 Celsius, and adding zirconium, titanium and graphite powder thereto to be dissolved therein, and b. keeping the temperature under agitation for 15-20 minutes, and performing casting molding to obtain an aluminum-zirconium-titanium-carbon (AlZrTiC) intermediate alloy having dispersed ZrC and Al.sub.4C.sub.3 mass points and a chemical composition consisting of: 0.1%10% Zr, 0.1%10% Ti, 0.01%0.3% C, and Al in balance, based on weight percentage.

3. A method comprising the steps of: a. melting commercially pure aluminum, heating to a temperature of 1000-1300 Celsius, and adding zirconium, titanium and graphite powder thereto to be dissolved therein, and b. keeping the temperature under agitation for 15-20 minutes, and performing casting molding to obtain an aluminum-zirconium-titanium-carbon (AlZrTiC) intermediate alloy having dispersed ZrC and Al.sub.4C.sub.3 mass points and a chemical composition consisting of: 1%5% Zr, 1%5% Ti, 0.1%0.3% C, and Al in balance, based on weight percentage.

4. The method of claim 1, wherein mAl.sub.4C.sub.3.nZrC.pTiC particle agglomerates are present in the intermediate alloy wherein m:n:p is within the ranges (0.6-0.75):(0.1-0.2):(0.1-0.2) respectively.

5. The method of claim 2, wherein mAl.sub.4C.sub.3.nZrC.pTiC particle agglomerates are present in the intermediate alloy wherein m:n:p is within the ranges (0.6-0.75):(0.1-0.2):(0.1-0.2) respectively.

6. The method of claim 3, wherein mAl.sub.4C.sub.3.nZrC.pTiC particle agglomerates are present in the intermediate alloy wherein m:n:p is within the ranges (0.6-0.75):(0.1-0.2):(0.1-0.2) respectively.

7. The method of claim 1, further comprising: c. melting pure magnesium under protection of a gas mixture of SF.sub.6 and CO.sub.2 and heating to 710 C.; d. adding 1% of the AlZrTiC intermediate alloy; e. holding the magnesium and AlZrTiC intermediate alloy mixture at 710 C. under agitation; and f. casting the magnesium and AlZrTiC intermediate alloy mixture.

8. The method of claim 2, further comprising: c. melting pure magnesium under protection of a gas mixture of SF.sub.6 and CO.sub.2 and heating to 710 C.; d. adding 1% of the AlZrTiC intermediate alloy; e. holding the magnesium and AlZrTiC intermediate alloy mixture at 710 C. under agitation; and f. casting the magnesium and AlZrTiC intermediate alloy mixture.

9. The method of claim 3, further comprising: c. melting pure magnesium under protection of a gas mixture of SF.sub.6 and CO.sub.2 and heating to 710 C.; d. adding 1% of the AlZrTiC intermediate alloy; e. holding the magnesium and AlZrTiC intermediate alloy mixture at 710 C. under agitation; and f. casting the magnesium and AlZrTiC intermediate alloy mixture.

Description

BRIEF DESCRIPTION OF DRAWING

(1) FIG. 1 is the SEM calibration graph of AlZrTiC intermediate alloys magnified by 3000;

(2) FIG. 2 is the energy spectrum of point A in FIG. 1;

(3) FIG. 3 is the grain microstructure of pure magnesium; and

(4) FIG. 4 is the grain microstructure of pure magnesium subjected to grain refining by the AlZrTiC intermediate alloy.

DETAILED DESCRIPTION

(5) The present invention can be further clearly understood in combination with the particular examples given below, which, however, are not intended to limit the scope of the present invention.

Example 1

(6) 948.5 kg commercially pure aluminum (Al), 30 kg zirconium (Zr) scrap, 20 kg titanium (Ti) scrap and 1.5 kg graphite powder were weighed. The aluminum was added to an induction furnace, melt therein, and heated to a temperature of 1050 C.10 C., in which the zirconium scrap, the titanium scrap and the graphite powder were then added and dissolved. The resultant mixture was kept at the temperature under mechanical agitation for 100 minutes, and directly cast into Waffle ingots, i.e., aluminum-zirconium-titanium-carbon (AlZrTiC) intermediate alloy. FIG. 1 shows the SEM photographs of AlZrTiC intermediate alloy at 3000 magnification, in which the gray blocks are larger particles, having a particle size of 20 m100 m; and the polygonal thin sheets are smaller particles, having a particle size of 110 m.

(7) FIG. 2 is an energy spectrum of A area in FIG. 1. The standard samples used in the test were Al:Al.sub.2O.sub.3; Zr:Zr; Ti:Ti; C:CaCO.sub.3, and Zr:Zr, and the atom percentages were 51.56% C, 37.45% Al, 7.52% Zr and 3.47% Ti, respectively.

Example 2

(8) 942.3 kg commercially pure aluminum (Al), 45 kg zirconium (Zr) scrap, 10 kg titanium (Ti) scrap and 2.7 kg graphite powder were weighed. The aluminum was added to an induction furnace, melt therein, and heated to a temperature of 1200 C.10 C., in which the zirconium scrap, the titanium scrap and the graphite powder were then added and dissolved. The resultant mixture was kept at the temperature under mechanical agitation for 30 minutes, and directly cast into Waffle ingots, i.e., an aluminum-zirconium-titanium-carbon (AlZrTiC) intermediate alloy.

Example 3

(9) 978 kg commercially pure aluminum (Al), 10 kg zirconium (Zr) scrap, 11 kg titanium (Ti) scrap, and 1 kg graphite powder were weighed. The aluminum was added to an induction furnace, melt therein, and heated to a temperature of 1100 C.10 C., in which the zirconium scrap, the titanium scrap and the graphite powder were then added and dissolved. The resultant mixture was kept at the temperature under mechanical agitation for 45 minutes, and directly cast into Waffle ingots, i.e., an aluminum-zirconium-titanium-carbon (AlZrTiC) intermediate alloy.

Example 4

(10) 972.6 kg commercially pure aluminum (Al), 25 kg zirconium (Zr) scrap, 1.4 kg titanium (Ti) scrap, and 1 kg graphite powder were weighed. The aluminum was added to an induction furnace, melt therein, and heated to a temperature of 1300 C.10 C., in which the zirconium scrap, the titanium scrap and the graphite powder were then added and dissolved. The resultant mixture was kept at the temperature under mechanical agitation for 25 minutes, and directly cast into Waffle ingots, i.e., an aluminum-zirconium-titanium-carbon (AlZrTiC) intermediate alloy.

Example 5

(11) 817 kg commercially pure aluminum (Al), 97 kg zirconium (Zr) scrap, 83 kg titanium (Ti) scrap, and 3 kg graphite powder were weighed. The aluminum was added to an induction furnace, melt therein, and heated to a temperature of 1270 C.10 C., in which the zirconium scrap, the titanium scrap and the graphite powder were then added and dissolved. The resultant mixture was kept at the temperature under mechanical agitation for 80 minutes, and directly cast into Waffle ingots, i.e., an aluminum-zirconium-titanium-carbon (AlZrTiC) intermediate alloy.

Example 6

(12) 997.5 kg commercially pure aluminum (Al), 1 kg zirconium (Zr) scrap, 1.2 kg titanium (Ti) scrap, and 0.3 kg graphite powder were weighed. The aluminum was added to an induction furnace, melt therein, and heated to a temperature of 1270 C.10 C., in which the zirconium scrap, the titanium scrap and the graphite powder were then added and dissolved. The resultant mixture was kept at the temperature under mechanical agitation for 120 minutes, and cast and rolled into coiled wires of aluminum-zirconium-titanium-carbon (AlZrTiC) intermediate alloy having a diameter of 9.5 mm.

Example 7

(13) Pure magnesium was melt in an induction furnace under the protection of a mixture gas of SF.sub.6 and CO.sub.2, and heated to a temperature of 710 C., to which 1% AlZrTiC intermediate alloy prepared according to examples 1-6 were respectively added to perform grain refining. The resultant mixture was kept at the temperature under mechanical agitation for 30 minutes, and directly cast into ingots to provide 6 groups of magnesium alloy sample subjected to grain refining.

(14) The grain size of the samples were evaluated under GB/T 6394-2002 for the circular range defined by a radius of to from the center of the samples. Two fields of view were defined in each of the four quadrants over the circular range, that is, 8 in total, and the grain size was calculated by cut-off point method.

(15) Referring to FIG. 3, it shows the grain microstructure of pure magnesium without grain refining. The pure magnesium without grain refining exhibited columnar grains having a width of 300 m2000 m and in scattering state. FIG. 4 shows the grain microstructure of pure magnesium subjected to grain refining. The 6 groups of magnesium alloys subjected to grain refining exhibited equiaxed grains with a width of 50 m200 m.

(16) The results of the tests show that the AlZrTiC intermediate alloys according to the present invention have very good effect in refining the grains of pure magnesium.

(17) The AlZrTiC intermediate alloy has great nucleation ability and in turn excellent ability in refining the grains of magnesium and magnesium alloys. It has good wrought processing performance, and can be easily rolled into a wire material of 910 mm for industrial production. As a grain refiner, the intermediate alloy is industrially applicable in the casting and rolling of magnesium and magnesium alloy profiles.