Deformation-driven solid-phase extrusion device and one-step alloy bar preparation method by using same

Abstract

A deformation-driven solid-phase extrusion device and a one-step alloy bar preparation method by using the same are provided. The device includes a stir tool, an extrusion container and an ejector rod. The stir tool has an integral structure composed of an upper mounting part and a lower working part and having a hollow channel. The lower working part is disposed in a groove of the extrusion container, and the ejector rod is disposed in the hollow channel of the stir tool. The method includes adding alloy powder to the extrusion container, enabling the stir tool to exert a pressure and revolve at a high speed to cause large plastic deformation of the powder and generate heat by friction and deform among powder and the friction working surface of the working part, sintering the alloy powder and extruding the same through the hollow channel of the stir tool.

Claims

1. A one-step alloy bar preparation method by using a deformation-driven solid-phase extrusion device, the deformation-driven solid-phase extrusion device comprising a stir tool, an extrusion container and an ejector rod, wherein the stir tool has an integral structure composed of an upper mounting part and a lower working part and having a hollow channel; an anti-drag groove is formed in an outer surface of the lower working part; the lower working part is disposed in a groove of the extrusion container; and the ejector rod is disposed in the hollow channel of the stir tool; the method comprising following steps of: adding alloy powder to the extrusion container; setting a rotating speed of the stir tool to a range of 50 rpm to 10000 rpm, setting a pressing speed of the stir tool to a range of 0.1 mm/min to 10 mm/min and an upsetting pressure of the ejector rod to a range of 5 MPa to 50 MPa; simultaneously performing operations of exerting the upsetting pressure with the range of 5 MPa to 50 MPa on the ejector rod, and enabling the stir tool to revolve at the rotating speed with the range of 50 rpm to 10000 rpm and to be pressed downwards at the pressing speed with the range of 0.1 mm/min to 10 mm/min, so as to sinter the alloy powder in the extrusion container to produce sintered products and extrude the sintered products through the hollow channel of the stir tool against the upsetting pressure on the ejector rod, such that one-step deformation-driven solid-phase extrusion is carried out to obtain the alloy bar.

2. The method according to claim 1, wherein a ratio of diameters of the lower working part and the hollow channel is 2:1 to 10:1.

3. The method according to claim 1, wherein a mounting surface is formed in an outer surface of the upper mounting part.

4. The method according to claim 1, wherein a friction working surface in a bottom of the lower working part is an inner concave ring surface.

5. The method according to claim 4, wherein the inner concave ring surface is sunken inwardly by 5?.

6. The method according to claim 1, wherein the stir tool is made of a steel, a cemented carbide, a tungsten-rhenium alloy or ceramics.

7. The method according to claim 1, wherein the extrusion container is made of a magnesium alloy, an aluminum alloy, a zinc alloy, a copper alloy, a titanium alloy or a steel.

8. The method according to claim 1, wherein the ejector rod is made of a steel, a cemented carbide, a tungsten-rhenium alloy or ceramics.

9. The method according to claim 1, wherein one end of the ejector rod is an expanded end.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic structural diagram of a deformation-driven solid-phase extrusion device according to the present disclosure.

(2) FIG. 2 is a schematic structural diagram of a stir tool according to the present disclosure.

(3) FIG. 3 is a schematic structural diagram of an extrusion container according to the present disclosure.

(4) FIG. 4 is a schematic structural diagram of an ejector rod according to the present disclosure.

(5) FIG. 5 is an electron back-scattered diffraction (EBSD) image of an alloy bar obtained according to specific embodiment 1 of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Specific Embodiment 1

(6) A deformation-driven solid-phase extrusion device provided in this embodiment includes a stir tool 1, an extrusion container 2 and an ejector rod 3. The stir tool has an integral structure composed of an upper mounting part 1-1 and a lower working part 1-2, and having a hollow channel 1-3. An anti-drag groove 1-2-1 is formed in an outer surface of the lower working part 1-2. The lower working part 1-2 is disposed in a groove 2-1 of the extrusion container 2, and the ejector rod 3 is disposed in the hollow channel 1-3 of the stir tool 1. The upper mounting part 1-1 and the lower working part 1-2 are cylinders. A mounting surface 1-1-1 is formed in an outer surface of the upper mounting part 1-1. A friction working surface 1-2-2 in a bottom of the lower working part 1-2 is an inner concave ring surface. One end of the ejector rod 3 is an expanded end 3-1. As show in FIG. 1, the reference character 4 denotes alloy powder, and the reference character 5 denotes the alloy bar.

(7) The upper mounting part 1-1 has a diameter of 19.9 mm.

(8) The lower working part 1-2 has a diameter of 24 mm.

(9) The hollow channel 1-3 has a diameter of 5 mm.

(10) The inner concave ring surface is sunken inwardly by 5?.

(11) The extrusion container 2 has an inner diameter equal to the diameter of the lower working part 1-2.

(12) The expanded end 3-1 has a diameter equal to the diameter of the hollow channel 1-3.

(13) The stir tool 1 is made of W6Mo5Cr4V2 steel with Vickers microhardness of 850 HV.

(14) The extrusion container 2 is made of 6082-T6 aluminum alloy with Vickers hardness of 103 HV.

(15) The ejector rod 3 is made of W6Mo5Cr4V2 steel with Vickers microhardness of 850 HV.

(16) The device operates according to the following principle: the extrusion container 2 is clamped on a fixture, and the stir tool 1 is clamped on a spindle of a machine with the mounting surface 1-1-1 of the upper mounting part 1-1 being clamped. The ejector rod 3 is arranged in the hollow channel 1-3 of the stir tool 1 through the spindle of the machine. The stir tool 1 is enabled to revolve at a high speed and exert a pressure under displacement control. The ejector rod 3 exerts an upsetting pressure under the control of the pressure to cause large plastic deformation of the powder and generate heat by friction and deform among powder and the friction working surface of the working part, so that the alloy powder in the extrusion container 2 is sintered and extruded through the hollow channel 1-3 of the stir tool 1 against the upsetting pressure of the ejector rod 3. Thus, an ultrafine-grained alloy bar is prepared by one step.

(17) A one-step alloy bar preparation method by using the above-described deformation-driven solid-phase extrusion device provided in this embodiment includes the following steps of: adding the alloy powder 4 to the extrusion container 2, setting a rotating speed of the stir tool 1 to 800 rpm, a pressing speed of the stir tool 1 to 2 mm/min and the upsetting pressure of the ejector rod 3 to 15 MPa, and then carrying out one-step deformation-driven solid-phase extrusion to obtain the alloy bar 5.

(18) The alloy powder is 6082 aluminum alloy powder.

(19) The one-step deformation-driven solid-phase extrusion is carried out in argon atmosphere.

(20) Tests

(21) Tests were conducted on the alloy bar obtained according to the above embodiment with respect to porosity, tensile strength and grain size, and results are as follows:

(22) 1. By the method provided in this embodiment, the porosity of the alloy bar was reduced to 0.05%, and the obtained alloy bar 5 has a tensile strength of 375 MPa and elongation of 15.2%.

(23) 2. FIG. 5 shows the EBSD image of the ultrafine-grained structure of the alloy bar. From FIG. 5, it could be seen that the alloy bar obtained according to this embodiment has an average grain diameter of 1.2 ?m.