CN1332058C - Prepn of rod superfine crystal material - Google Patents

Abstract

The invention discloses a method for preparing a rod-shaped ultrafine-grained material, which is characterized in that: the rod-shaped metal material (1) to be refined is stuck between a fixing fixture (10) and a rotating fixture (3), and is passed through an intermediate frequency power supply ( 6) and the induction coil (7) to locally heat the rod-shaped metal material (1); when the temperature reaches the set value, the servo motor (4) drives the rotating fixture (3) to rotate, and under the action of torsional shear stress, the deformation The metal grains at the zone (9) are broken and refined; the induction coil (7) is gradually moved along the axial direction of the material (1); at the same time, the cooling ring (45) moves synchronously with the induction coil (7), cooling the deformation zone (9 ) maintains the refined fine-grain structure; when the induction coil (7) moves to the other end of the rod-shaped metal material (1), a section of ultra-fine-grain structure rod can be obtained. The invention has one-time forming, high degree of deformation, low tonnage of equipment used, and can reduce the cost of ultra-fine crystal materials.

Description

Preparation method of rod-shaped ultrafine-grained material

Technical field:

The invention relates to a preparation method of a rod-shaped ultrafine crystal material.

Background technique:

The general methods for preparing ultrafine-grained materials include: inert gas condensation method, gas phase precipitation method, mechanical method, mechanical alloying method, strong plastic deformation method, etc. The strong plastic deformation method is divided into two types, one is the high-pressure torsional plastic deformation method, and the other is the S-type equal radial extrusion method.

See Figure 6. In the fourth issue of "Materials Herald" in 1999, Shen Hui's article "Preparation of Nanomaterials Ni and Ni/SiO ₂ by Severe Plastic Deformation" used high-pressure torsional plastic deformation method, for thickness 0.2mm, diameter An ultra-fine-grained material with an average grain size of about 52nm was prepared by high-pressure torsion for an 8mm disc-shaped Ni sample. VRGertsman recorded in "scripta metallurgica and mechanical" 1994, page 229, "On the structure and strength of ultrafine-grained copper produced by severe plastic deformation" the use of high-pressure torsional plastic deformation method, for the thickness of 200μm, the diameter of 3mm The metal disc material is twisted under high pressure to prepare an ultra-fine grain structure with an average grain diameter of 170nm. The defect of this method is that only small pieces of material can be processed, and no large-area or massive ultra-fine-grained structure material can be prepared, so it cannot be applied to industrial production.

See Figure 7, Z.Y.Liu in "Materials science and Engineering" 1998 A242 volume 137-140 pages "The effect of cumulative large plastic strain on the structure and properties of a Cu-Znalloy", recorded the use of S-type equal diameter In the lateral extrusion method, the copper-zinc alloy bar containing 38% zinc is extruded several times under high temperature conditions, and finally an ultra-fine-grained material with an average grain diameter of 0.3-0.4 μm is produced. The disadvantage of this method is that the tonnage of the equipment is high, the degree of deformation is low, and it needs to be repeated many times.

Invention content:

The purpose of the present invention is to provide a method for preparing rod-shaped ultrafine-grained material.

The technical solution adopted by the present invention to solve the technical problem is: a preparation method of a rod-shaped ultrafine-grained material, characterized in that:

1) The rod-shaped metal material (1) to be refined is clamped between the fixed fixture (10) and the rotating fixture (3), and the rod-shaped metal material (1) is locally processed by the intermediate frequency power supply (6) and the induction coil (7). Heating, the heating temperature is lower than the dynamic recrystallization temperature of the material;

2) When the temperature reaches the set value, the servo motor (4) drives the rotating fixture (3) to rotate, and under the action of torsional shear stress, the metal grains in the deformation zone (9) are broken and refined;

3) By controlling the movement of the sliding table (44), the induction coil (7) gradually moves along the axial direction of the material (1) to change the heating area; at the same time, the cooling ring (45) moves synchronously with the induction coil (7), cooling the rod-shaped The area behind the deformation zone (9) on the metal material (1) maintains the refined fine-grain structure;

4) When the induction coil (7) moves from one end of the rod-shaped metal material (1) to be thinned to the other end, stop heating, cooling and twisting in sequence to obtain a section of ultra-fine-grained rod;

5) Perform annealing treatment on the formed rod with ultra-fine grain structure.

Compared with the prior art, the present invention has the advantages that, due to the thermal torsion offset method, a whole block of rod-shaped ultra-fine-grained material can be prepared, and it can be formed once, with high degree of deformation and low tonnage of the equipment used. The cost of ultrafine-grained materials is reduced.

Description of drawings:

Figure 1 is a schematic diagram of the preparation of rod-shaped ultrafine-grained materials by the thermal torsion migration method

Figure 2 is a schematic diagram of the preparation of ultrafine-grained materials by high-pressure torsional plastic deformation

Figure 3 is a schematic diagram of the preparation of ultrafine-grained materials by S-type equal diameter lateral extrusion method

Fig. 2 and Fig. 3 are accompanying drawings of background technology

In the figure 1-material, 2-bearing, 3-rotary fixture, -4-servo motor, 5-temperature sensor, 6-intermediate frequency power supply, 7-induction coil, 8-cooling system, 9-deformation zone, 10-fixing fixture, 61-press torsion die, 71-pressure head, 72-extrusion die.

Detailed ways:

Embodiment 1: Referring to Fig. 1, this example is to prepare rod-shaped ultra-fine-grained material by thermal torsion migration method, which belongs to a method for preparing rod (block)-shaped ultra-fine-grained material by deformation zone transfer method. The specific process is as follows: the rod-shaped metal material 1 to be refined is stuck between the fixed fixture 10 and the rotating fixture 3 . The rotary clamp 3 is driven by a servo motor 4 , and a torque sensor 41 is installed between the rotary clamp 3 and the servo motor 4 . The induction coil 7 and the intermediate frequency power supply 6 can locally heat the rod-shaped metal material 1 . The cooling ring 45 and the cooling system 8 can locally cool the rod-shaped metal material 1 . The temperature sensor 5 is used to measure the temperature of the heating zone.

The rod-shaped metal material 1 is locally heated by the intermediate frequency power supply 6 and the induction coil 7, and the heating temperature is lower than the dynamic recrystallization temperature of the material;

When the temperature reaches the set value, the rotary fixture 3 is driven by the servo motor 4 to rotate. Since the temperature of the induction heating area is higher than that of other areas and the deformation resistance is small, the plastic deformation is concentrated in the heating deformation area 9 . Due to the concentration of deformation, the deformation rate of the deformation zone 9 is high, and it is easy to reach a large strain degree. Under the action of torsional shear stress, the metal grains are easily broken to form fine grains. At the same time, due to the local deformation, the requirements for the loading capacity of the equipment are low, and the deformation process is easy to control.

When the temperature and degree of deformation of the initial heating deformation zone 9 reach the set value, and the grains are refined to a certain extent, by controlling the movement of the sliding table 44, the induction coil 7 is gradually moved along the axial direction of the material 1, and the heating area is changed. . Simultaneously, the cooling ring 45 moves synchronously with the induction coil 7 with the movement of the sliding table 44, starts the cooling system 8, cools the area behind the deformation zone 9 on the rod-shaped metal material 1, and maintains the refined fine-grain structure. In this way, with the movement of the slide table 44, the heated deformation zone 9 on the rod-shaped metal material 1 moves together with the induction coil 7, so that the crystal grains in the new heated deformation zone 9 are refined and maintained. Along with the continuous movement of the heated deformation zone 9, a continuous rod (block)-shaped refined metal body will be formed.

When the induction coil 7 moves from one end to the other end of the rod-shaped metal material 1 to be thinned, heating, cooling and twisting are stopped sequentially. The rod-shaped metal material 1 is removed from the fixture, and the transition sections at both ends are removed to obtain a rod with an ultra-fine grain structure.

By controlling the heating temperature, twisting speed and moving speed, the degree of deformation and the degree of dynamic recrystallization in the torsional deformation process can be adjusted to obtain different degrees of refined grains inside the rod-shaped metal material 1 .

Finally, the rod-shaped metal material 1 with refined grains is properly tempered to reduce residual stress and stabilize the structure.

Claims (1)

1, a kind of preparation method of rod superfine crystal material is characterized in that:

1) bar-shaped metal materials (1) for the treatment of thinning microstructure is stuck between stationary fixture (10) and the rolling clamp (3), by intermediate frequency power supply (6) and ruhmkorff coil (7) bar-shaped metal materials (1) is carried out local heating, Heating temperature is lower than the dynamic recrystallization temperature of material;

2) after temperature reaches set(ting)value, by servomotor (4) driven rotary anchor clamps (3) rotation, under the torsional shear stress, the broken refinement of the metal grain that distorted area (9) are located;

3) by controlling moving of slide unit (44), make ruhmkorff coil (7) move axially the conversion heating region gradually along material (1); Simultaneously, cooling ring (45) and the same moved further of ruhmkorff coil (7), cooling bar-shaped metal materials (1) goes up the zone at rear, distorted area (9), keeps the fine grained texture of refinement;

4) when ruhmkorff coil (7) when an end of the bar-shaped metal materials (1) for the treatment of refinement moves to the other end, stop heating successively, cool off and reverse, can obtain one section ultrafine-grained's bar;

5) in type ultrafine-grained (UFG) microstructure bar is carried out anneal.

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