Method for eliminating hollow defect in atomized alloy powder

Abstract

The invention relates to a method for eliminating hollow defects in atomized superalloy powder, and pertains to the field of powder metallurgy materials. A ball-milling processing is conducted on the atomized alloy powder to eliminate the hollow defect, obtain solid powder and increase powder utilization efficiency. By controlling mill ball diameters, mass ratio of mill balls with different diameters, mass ratio of ball to powder and ball milling time, a multi-directional impact on the powder is achieved, thereby control powder shape and obtain solid spherical powder. The invention eliminates powder hollow defect by using ball milling process and equipment. This invention with high powder utilization efficiency, short ball milling time and simple operating process, can be used for large-scale preparation and application.

Claims

1. A method for eliminating hollow defect in atomized alloy powder, wherein the method comprises mechanical ball milling on the atomized alloy powder to eliminate the powder hollow defect, wherein four kinds of mill balls characterized by having different diameters are used in the mechanical ball milling process, the four diameters of the mill balls are in ranges of 9-11 mm, 7-9 mm, 5-7 mm, and 4-6 mm respectively, and all of the mill balls are combined according to mass ratio of 1:2.5-3.5:0.5-1.5:4-6 in descending order of the diameters.

2. The method for eliminating the hollow defect in atomized alloy powder according to claim 1, wherein the ball milling is under the protection of an inert gas.

3. The method for eliminating the hollow defect in atomized alloy powder according to claim 2, wherein the mechanical ball milling is carried out in any one of a planetary ball mill, stirring ball mill, or drum-type ball mill.

4. The method for eliminating the hollow defect in atomized alloy powder according to claim 3, wherein the atomized alloy powder is loaded into a ball milling tank with a mass ratio of the balls to powder as (812):1, and the ball milling is performed in the planetary ball mill with a ball mill rotating speed of 250350 r/min and ball milling time of 14 h under the protection of an inert gas.

5. The method for eliminating the hollow defect in atomized alloy powder according to claim 3, wherein the atomized alloy powder is loaded into a ball milling tank with a mass ratio of the balls to powder mass ratio is (815):1, and the ball milling is performed in the stirring ball mill with a ball mill rotating speed of 60150 r/min and ball milling time of 26 h under the protection of an inert gas.

6. The method for eliminating the hollow defect in atomized alloy powder according to claim 1, wherein the four diameters of the mill balls are 10 mm, 8 mm, 6 mm, and 5 mm respectively, which are combined according to mass ratio of 1:3:1:5 in descending order of the diameters.

7. The method for eliminating the hollow defect in atomized alloy powder according to claim 6, wherein the atomized alloy powder is loaded into a ball milling tank with the balls to powder mass ratio is (812):1, the ball milling is performed in the planetary ball mill with a ball mill rotating speed of 250350 r/min, and ball milling time of 14 h under the protection of an inert gas.

8. The method for eliminating the hollow defect in atomized alloy powder according to claim 6, wherein the atomized alloy powder is loaded into a ball milling tank with the balls to powder mass ratio of (815):1, the ball milling is performed in the stirring ball mill with a ball mill rotating speed of 60150 r/min, and ball milling time of 26 h under the protection of an inert gas.

9. The method for eliminating the hollow defect in atomized alloy powder according to claim 1, wherein the atomized alloy powder is loaded into a ball milling tank with the balls to powder mass ratio of (812):1, the ball milling is performed in the planetary ball mill with a ball mill rotating speed of 250350 r/min and ball milling time of 14 h under the protection of an inert gas.

10. The method for eliminating the hollow defect in atomized alloy powder according to claim 1, wherein the atomized alloy powder is loaded into a ball milling tank with the balls to powder mass ratio of (815):1, the ball milling is performed in the stirring ball mill with a ball mill rotating speed of 60150 r/min, and ball milling time of 26 h under the protection of an inert gas.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a scanning electron microscope (SEM) image of cross-section of gas-atomized nickel-base superalloy powder according to embodiment 1 of the present invention.

(2) FIG. 2 is a SEM image of cross-section of mechanical ball-milling gas-atomized nickel-base superalloy powder according to embodiment 1 of the present invention.

(3) From the SEM observation in FIG. 1, some gas-atomized powder in embodiment 1 exhibits obvious hollow defects. For powder particle sample 1, 2, 3, and 4 in FIG. 1, the powder hollow defects are obvious, and the powder particle sizes show no difference compared to other powder in a same field of view.

(4) From the SEM observation in FIG. 2, no hollow defects are observed in gas-atomized powder by mechanical ball-milling in Embodiment 1. That is, the powder hollow defects are eliminated, and the powder sphericity is preferably kept.

DESCRIPTION OF THE EMBODIMENTS

(5) The following further describes the technical solution to the present invention with reference to specific embodiments and drawings.

Embodiment 1

(6) A gas-atomized nickel-base superalloy powder (the composition is Ni-20.6Co-13Cr-3.8Mo-2.1W-3.4Al-3.9Ti-2.4Ta-0.9Nb (wt. %)) is loaded into a ball milling tank with a ball to powder mass ratio as 8:1. Mill balls with different diameters of 10 mm, 8 mm, 6 mm, and 5 mm are used, and all of mill balls are combined according to a mass ratio of 1:3:1:5. The process is conducted under an argon gas as atmosphere as a protective gas after vacuumed. Ball milling is performed in a planetary ball mill with a ball-milling rotating speed of 250 r/min and ball-milling time of 3 h to obtain nickel-base superalloy powder without hollow defect.

(7) FIG. 1 is a SEM image of cross-section of gas-atomized nickel-base superalloy powder before ball-milling processing in this embodiment. In FIG. 1, significant hollow defects can be observed in some powders, and particle sizes of those powder presents no difference compared to other powder in a same field of view. FIG. 2 is a SEM image of cross-section of mechanical ball milling powder in this embodiment, and no hollow powder is observed. It indicates that mechanical ball-milling can eliminate powder hollow defect, and obtain completely solid powder.

Embodiment 2

(8) A Gas-atomized nickel-base superalloy powder (the composition is Ni-20.6Co-13Cr-3.8Mo-2.1W-3.4Al-3.9Ti-2.4Ta-0.9Nb (wt. %)) is loaded into a ball milling tank with a mass ratio of ball to powder as 10:1. Mill balls with different diameters of 9 mm, 7 mm, 5 mm, and 4 mm are used, and all of mill balls are combined according to a mass ratio of 1:3.5:1.5:6. The process is conducted under an argon gas as atmosphere as a protective gas after vacuumed. Ball milling is performed in a planetary ball mill with a ball-milling rotating speed of 300 r/min, and ball-milling time of 2 h to obtain nickel-base superalloy powder without hollow defect.

Embodiment 3

(9) A gas-atomized nickel-base superalloy powder (the composition is Ni-20.6Co-13Cr-3.8Mo-2.1W-3.4Al-3.9Ti-2.4Ta-0.9Nb (wt. %)) is loaded into a ball milling tank with a mass ratio of ball to powder as 10:1. Mill balls with different diameters of 11 mm, 9 mm, 7 mm, and 6 mm are used, and all of mill balls are combined according to a mass ratio of 1:2.5:0.5:4. The process is conducted under an argon gas as atmosphere as a protective gas after vacuumed. Ball milling is performed in a stirring ball mill with a ball-milling rotating speed of 100 r/min, and ball milling time of 3 h to obtain nickel-base superalloy powder without hollow defect.