CN1410561A - Deep cold rolling method of nano crystal metal material - Google Patents

Abstract

The invention discloses a method for deep cold rolling of nanocrystalline metal materials. It selects ordinary industrial metal materials and operates as follows: 1) hot rolling; 2) high temperature annealing, the temperature is in the γ region, that is, in the range of 940-950 ℃, and the time is 0.5-2 hours; 3) deep cold rolling, cold rolling The degree of deformation is above 90%, and the nanocrystalline metal material is obtained. The invention has the characteristics of wide selection range of materials, simple method, convenient operation, large size samples can be made, suitable for industrialization requirements and the like.

Description

Deep cold rolling method of nanocrystalline metal material

technical field

The invention relates to the cold rolling technology of nano crystal and metal material, in particular to a deep cold rolling method of nano crystal metal material.

Background technique

In the existing high-tech, the preparation of nanocrystalline materials is popular at home and abroad. The method is mainly inert gas evaporation and in-situ pressure preparation. Consistent, unstable performance, some people think that the elastic modulus of nanocrystalline materials is reduced by more than 50% compared with bulk samples, others think that the elastic modulus of nanocrystalline materials is reduced by no more than 8%, and some people think that there is no reduction. In addition, to turn nanocrystalline materials into structural materials, large samples need to be made, which is difficult to achieve with current methods, so most of their mechanical properties can only be measured by Vickers hardness, and it is difficult to do tensile performance experiments, making structural materials application is limited. In recent years, Russia R.Z.Valiev advocated (R.Z.Valiev, et al.Prog.Mater Sci., 45 (2000) 103-189)) to prepare nanocrystalline metal materials by deep cold working method, and found after only forging test: its structure The structure is very inhomogeneous, and it is considered that all traditional processing techniques are not suitable for preparing nanocrystalline materials. But in fact, the preparation of nanocrystalline metal materials by deep cold rolling method has not been reported yet.

Contents of the invention

In order to overcome the above-mentioned shortcomings, the object of the present invention is to provide a deep cold rolling method for nanocrystalline metal materials with a wide range of material choices, a simple method, and suitable for industrialization requirements.

In order to achieve the above object, the technical solution of the present invention is to select common industrial metal materials, and operate as follows: 1) hot rolling; 3) Deep cold rolling, the degree of cold rolling deformation is more than 90%, to obtain nanocrystalline metal materials.

The present invention has the following advantages:

1. Wide selection of materials. Since any metal can be rolled and processed, compared with the method of preparing nanocrystalline materials only with special materials in the prior art, the present invention is not limited to the selection of metal materials, which not only greatly broadens the application field, but also breaks R.Z.Valiev's traditional method of using Craftsmanship cannot make the perception of nanomaterials.

2. The method is simple and easy to operate. Since the cold processing of steel has been produced since the 1940s and 1950s, and the process is mature, the present invention is applicable to the conventional rolling method, and it does not involve some problems caused by other processes, such as the stability of the powder process, compaction density, etc., so it is very convenient .

3. It can make large size samples, which is suitable for industrialization requirements. The size of the samples produced by conventional heat treatment and cold rolling in the present invention can meet the needs of users (only related to the rolling mill used). Compared with the prior art, the mechanical property of the product of the present invention is better, and the sample size can be used for ordinary tensile property experiments.

4. The present invention adopts traditional technology, so the cost is low.

Detailed ways

Example 1

Follow the steps below:

1. Hot rolling: select ordinary industrial metal materials such as ordinary industrial process pure iron, and roll the pure iron to a thickness of 4 mm;

2. Heat treatment: high temperature annealing, high temperature to the γ region, that is, 940 ° C, keep for 1 hour;

3. Cold rolling: cold rolling the pure iron material with a thickness of 4 mm to 0.8 mm, and its cold rolling deformation is calculated as 98% according to the length, that is, the nanocrystalline pure iron material is obtained.

[(0.8～1.0)×74mm×arbitrary length] nanocrystalline pure iron can be made in the embodiment of the present invention. According to X-ray and transmission electron microscope analysis, the crystal grains of the present invention have reached the nanoscale range, and the grain size test results are shown in Table 1.

Table 1 is embodiment 1 grain size test result Grain size ^* Test Methods test unit 77～92nm X-ray Institute of Solid State, Chinese Academy of Sciences 22.5～49.6nm X-ray Institute of Metal Research, Chinese Academy of Sciences ~50nm TEM Northeastern University

Among them: ^* The effect of residual stress in the sample is deducted.

The inventive method has 3 characteristics:

(1) Adopt ordinary materials (iron: it is the basic element of steel; there is also ferromagnetism); (2) Ordinary processing technology (rolling), the grain size of the present invention has been processed with RZValiev's special processing, that is, deep plastic deformation (Sever The size obtained by Plastic Deformation (abbreviation: SPD) method is equivalent, that is, 100-200 nm, and the sample used by the SPD method is generally Φ20×(70-100) mm ³ ; (3) Larger samples can be made. The samples of the present invention are ready for tensile testing. As long as the capacity of the cold processing equipment is large enough, it is possible to make much larger nanomaterials. Compared with the limited application of surface nano-processing materials in the world, the invention is not limited by the processing materials.

Claims (1)

1. the deep cold rolling method of a nano crystal metal material is selected the general industry metallic substance, it is characterized in that: operation as follows: 1) hot rolling; 2) high temperature annealing, temperature be in the γ district, and promptly in 940～950 ℃ of scopes, the time is 0.5～2 hour; 3) deep cold rolling, cold roller and deformed degree are more than 90%, obtain nano crystal metal material.