SU1722690A1 - Unit for compacting rapidly cooled metal powders - Google Patents

Abstract

The invention relates to devices for compacting metal powders. The purpose of the invention is to improve the quality of products by improving their physico-mechanical properties. An aluminum alloy of composition AI-SI, obtained at a cooling rate of 106 K / s in the form of ribbons and fibers with a thickness of 20-80 µm and having a microcrystalline structure, was pressed. The blank 5 was molded at room temperature and a pressure of 500 MPa, heated to a temperature of 400 ° C and, at a given temperature, the axial force was extruded using a punch 1 through a conical matrix 3 with a taper angle of 2 a 90 °, the truncated cone of the extrusion point of which on the side of the punch, it is formed by an inclined cutting plane located at an angle to the horizontal of / 20 °. The degree of stretching was A 6.25, and the tensile strength of the compacted alloy during stretching was Ov 200 MPa. 1 il.

Description

The invention relates to powder metallurgy, in particular to devices for compressing articles from powder materials.

The purpose of the invention is to improve the quality of products by improving their physico-mechanical properties.

The drawing shows the proposed device, the cut.

The device consists of a punch 1, a container 2 installed in the cavity of the container of the matrix 3 with an extruding cone

4. The raw material is indicated by

5. The truncated cone of the extrusion point of the matrix 3 from the side of the punch is formed by an inclined cutting plane, and the inclination angle ft is within

I / ji arctg

(one)

where a is a half-angle of a truncated cone of a matrix formed by parallel horizontal cutting planes;

2

I 1-7G-1 - the degree of stretching;

No) d is the diameter of the calibration channel of the matrix;

D is the diameter of the cavity of the container.

The device works as follows.

In the heated container 2 is placed pre-molded and heated to a predetermined temperature, the workpiece 5. With the help of the punch 1 put pressure along the axis of the container, thereby compaction of the powder billet by extrusion through the matrix 3 with the extruded truncated cone 4.

Since the extruded truncated cone 4 is formed from the side of the punch by an inclined secant plane with an angle of inclination I, then they appear in the deformation zone. asymmetrical non-uniform fields of external friction and radial compression forces. This leads to an increase in the non-uniformity of the flow rates of the microvolumes of the material in the deformation zone, as a result of which more intense frictional forces arise at the interparticle contacts, which, in turn, generate additional shear deformations. Shear deformations contribute to the destruction of oxide films on the surface of the material particles, the adhesion interaction of the particles, the mixing of the material layers, the better development of the material in the deformation zone, and, consequently, the improvement of the physicomechanical properties of the blanks and products.

The angle of inclination / 3 of the section plane depends on many factors, the main of which are: the physicomechanical properties of the material being compacted, the state of the oxide films on the surface of the particles and their geometry; compaction temperature, degree of drawdown. However, the angle θ / 3 should not exceed the value defined by formula (1).

Otherwise, the technical solution loses its meaning.

Example. An aluminum alloy of composition AI-SI, obtained at a cooling rate of 106 K / s in the form of ribbons and

fibers with a thickness of 20-80 μm, having a microcrystalline structure; Pre-molded preform at room temperature under a pressure of 500 MPa. Then, the billet was heated (by one of the known methods) to a temperature of 400 ° C, placed in a heated container to maintain the set temperature. Pressure was applied (punch) along the pre-compaction axis of the workpiece,

thus carried out the extrusion through a conical matrix with an inclined secant plane from the side of the punch, located at an angle / 3 20 ° and the angle of the cone 2 and 90 °. The degree of stretching was I 6.25.

An alloy compacted with a known device has a tensile strength when stretched to ø 155 MPa. When compacting an alloy with the proposed device

tensile strength is increased to Ov 200 MPa, i.e. by 29%.

From the example it is seen that the compacting of fast-cooling microcrystalline powders in accordance with the invention

improves product quality by improving

nor physicomechanical properties in comparison with the known.

The output and calibration parts of the matrix can have different profiles. 5 The application of the proposed device for compacting predominantly rapidly cooled microcrystalline and amorphous alloys is due to their special physicomechanical and structural properties, as well as the nature

compaction. Such powders are rigid, not sufficiently compactable under normal conditions, do not allow to increase their plasticity by heating to high temperatures, since there is an irreversible change in the structure and therefore these powder materials require additional deformation shifts, which is done this device.

The technical and economic efficiency of the invention is to improve the quality of products from rapidly cooled metal powders and fibers, including amorphous ones, by creating intense shear deformations in the volume of the deformation zone, improving the physicomechanical properties 1.3-1.5 times, expanding the nomenclature of products obtained by powder metallurgy.

Formula a b b shadow

A device for compacting rapidly cooled metal powders, comprising a punch, a container and a die with an extrusion point in the form of a truncated

cone, different from that. what. in order to improve the quality of products by improving their physico-mechanical properties, the truncated cone of the die extrusion point on the side of the punch is formed by an inclined cutting plane, and its angle of inclination is within yST I

  where a- half angle

| Ј | arctgH j-ctga

a truncated cone of a matrix formed by parallel horizontal cutting planes;

A (D / d) 2 — degree of stretching; d is the diameter of the calibration channel of the matrix;

D is the diameter of the cavity of the container.

Claims (1)

A device for compacting rapidly cooled metal powders containing a punch, a container and a die with an extrusion point in the form of a truncated cone, characterized in that. that, in order to improve the quality of products by improving their physical and mechanical properties, the truncated cone of the extrusion point of the matrix on the side of the punch is formed by an inclined secant plane, and its angle of inclination β is within l / Jl <arctan Γ ^ -_ μ | ctg a, where a is the half-angle 10 of the truncated cone of the matrix formed by parallel horizontal secant planes; And "(D / d) ² - the degree of drawing; d is the diameter of the calibrating channel of the matrix15; D is the diameter of the container cavity.