Powder blank with self-healing nature and method and related devices for making the same

Abstract

This case discloses a powder preform with self-healing properties and a method and related apparatus for preparing it. The method includes: filling the powder into a container with a conical wall; shaping the powder so that the central portion of the upper surface of the powder is raised relative to the peripheral portion; and pressing the powder in the container to form a powder preform in which the peripheral portion of the upper surface is curved downward and the peripheral portion of the lower surface is tapered downward.

Claims

1. A method for preparing a powder preform with self-healing properties, the method comprising: A container is provided having a bottom plane, an annular sidewall, a conical wall, and an opening, wherein the diameter of the annular sidewall is larger than the diameter of the bottom plane, the conical wall tapers from the bottom end of the annular sidewall to the outer periphery of the bottom plane, and the opening is provided on the opposite side of the bottom plane; an appropriate amount of powder is filled into the container; the powder is shaped to make the center of the upper surface of the powder bulge relative to the periphery; and the powder is pressed to form a powder blank in the container with the periphery of the upper surface curved downward and the periphery of the lower surface tapering downward; wherein the powder shaping is performed before or during the powder pressing process.

2. The method of claim 1, wherein the bottom plane of the container has a region that can hold powder thereon but allows fluid to pass through, and wherein the peripheral portion of the upper surface of the powder blank transitions into a planar portion at the edge corresponding to the region.

3. The method of claim 1, wherein shaping the powder is achieved by agitating the powder or vibrating the container or a pressing device for pressing the powder to cause lateral displacement of the powder.

4. The method of claim 1, wherein shaping the powder is performed by operating a shaping device comprising: A blade assembly configured to rotate relative to the container, the blade assembly including at least one blade, the at least one blade including a vertical curved surface and a curved surface located below the vertical curved surface, wherein the vertical curved surface is configured to push powder in the container toward the center portion of the container, and wherein the curved surface is configured to compact the powder in the container.

5. The method of claim 1, wherein pressing the powder is performed by operating a pressing device, the pressing device comprising: A pressing member having a pressing surface below, wherein the pressing surface includes a curved portion located at the edge of the pressing surface and a flat portion surrounded by the curved portion and recessed relative to the curved portion.

6. The method of claim 2, further comprising: injecting fluid into the container through the opening, wherein the fluid creates uniform pressure on the upper surface of the powder preform and permeates through the powder preform.

7. A powder preform with self-healing properties, the powder preform comprising: The upper surface; The upper surface has a downward-curving periphery, and the lower surface has a downward-tapering cone shape.

8. The powder preform of claim 8, wherein the lower surface has a shape complementary to a container for extraction of the powder preform, a bottom plane of the container having a region through which fluid can flow, and wherein the radius of curvature of the peripheral portion of the upper surface is equal to the length of the shortest distance from the edge of the region through which fluid can flow to the edge of the upper surface.

9. The powder preform of claim 9, wherein the upper surface transitions into a planar portion vertically above the edge of the region through which the container allows fluid to flow, wherein the planar portion is at a distance from the bottom plane equal to the radius of curvature.

10. The powder preform of claim 8, wherein the powder preform has a uniform density.

Images