Multi-scale gradient composite structure high-strength and high-toughness metal material and preparation method thereof

Abstract

The invention provides a high-strength and high-toughness metal material with a multi-scale gradient composite structure and a preparation method thereof, and belongs to the technical field of composite metal materials. Comprising preparation of a micro gradient structure and preparation of a macro laminated structure. The microscopic gradient structure preparation and the macroscopic laminated structure preparation are in an explosion hardening mode and an explosion welding mode respectively. The method provided by the invention is expected to synergistically exert the advantages of a nano gradient structure and a layered structure in the aspects of strengthening and toughening, and a feasible and efficient structural material design strategy is provided for the high-strength and high-toughness requirements of materials and structures in extreme loading environments such as high strain rate and the like.

Description

Technical Field

[0001] The invention provides a high-strength and high-toughness metal material with a multi-scale gradient composite structure and a preparation method thereof, belonging to the technical field of composite metal materials. Background Art

[0002] Metal materials are widely used in engineering fields such as shipbuilding and national defense. However, with the development of technology, a single homogeneous metal plate can no longer fully meet engineering needs. First, with the improvement of strength and toughness, the preparation cost of metal materials often increases significantly; second, homogeneous materials cannot solve the antagonistic effect of strength and toughness. While the strength is increased, the brittleness often increases simultaneously, which restricts the application scope of the material.

[0003] The main shortcomings of current technology are:

[0004] (1) Single preparation method. Most research and applications are only for gradient structures or laminated structures. The design in the present invention fully combines the two, and improves the performance of the material matrix while ensuring the surface strength and hardness.

[0005] (2) Engineering applications are relatively limited. Affected by the thickness of the gradient layer, the size of metal materials with nano-gradient structures is often small. The increase in size leads to a decrease in the concentration of the gradient layer, which results in the problem of reduced effect of the gradient layer not being fully solved. The laminated structure can adjust the material properties on a macro scale, but it cannot solve or reduce the antagonistic effect between material strength and toughness. Summary of the invention

[0006] The present invention aims to reduce the material preparation cost while regulating the strength and toughness of the material, so that the metal material can meet more working conditions. The multi-scale gradient composite material is prepared by coupling explosive hardening and explosive welding. On the one hand, the surface gradient structure and the laminated structure are used to solve the strength-toughness antagonism. On the other hand, the composite structure is used to regulate the materials used, and some high-cost metal materials are replaced by low-cost metal materials, thereby achieving the purpose of reducing the preparation cost.

[0007] The method provided by the present invention mainly consists of two parts. The first part is the preparation of microscopic gradient structure, and the second part is the preparation of macroscopic laminated structure.

[0008] The invention adopts explosive hardening and explosive welding to prepare multi-scale gradient composite structure metal materials, wherein the former is used to prepare microscopic gradient structures; and the latter is used to prepare macroscopic laminated structures.

[0009] The specific technical solution is:

[0010] First, the cover plate is loaded with 4 mm thick C-4 explosive to produce a gradient layer; the cover plate material is 10CrNi3MoV, and the base plate material is 30CrMnSiNi2MoVE;

[0011] Subsequently, expanded ammonium nitrate explosives were used for lamination, with the spacing between the cover plate and the base plate being 8 mm, and finally a multi-scale gradient composite structure high-strength and high-toughness metal material was obtained.

[0012] Among them, the detonation speed of C-4 explosive is 8000m / s and the density is 1.6g / cm 3 ; The detonation velocity of expanded ammonium nitrate explosive is 2700m / s and the density is 1.05g / cm 3 .

[0013] The method provided by the present invention is expected to synergistically leverage the advantages of nano-gradient structures and layered structures in terms of enhancement and toughness, and provide a feasible and efficient structural material design strategy for the high strength and toughness requirements of materials and structures under extreme loading environments such as high strain rates. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The stress-strain curve of the material of the embodiment is

[0015] Figure 2 It is a schematic diagram of the preparation method of the multi-scale gradient composite structure material of the present invention. DETAILED DESCRIPTION

[0016] The specific technical solution of the present invention is described in conjunction with the accompanying drawings.

[0017] The design method of the present invention mainly consists of two parts. The first part is the preparation of the microscopic gradient structure, and the second part is the preparation of the macroscopic laminated structure.

[0018] The design method of the present invention adopts explosive hardening and explosive welding to prepare multi-scale gradient composite structure metal materials, wherein the former is used to prepare microscopic gradient structures; and the latter is used to prepare macroscopic laminated structures.

[0019] After a long period of research, the explosion hardening technology has become relatively mature and is mainly used for metal materials, including titanium, steel, copper, etc. During preparation, high-detonation-velocity (8000m / s) explosives are attached to the surface of the material. The loading generated by the explosion of the explosives causes the surface of the material to deform at a high strain rate, thereby achieving the effect of grain refinement. Affected by the depth of load propagation, a gradient structure from nanocrystalline to coarse crystal can be achieved inside the material. Grain refinement can significantly improve the strength, hardness, corrosion resistance and other properties of the material, and the resulting gradient structure effectively reduces the antagonistic effect of strength-toughness. Compared with other preparation methods, explosion hardening can increase the thickness of the gradient layer and has higher engineering application value.

[0020] Due to the differences in performance between different metal materials, traditional welding methods often affect material properties and even lead to ineffective welding. Explosion welding is widely used in engineering manufacturing because it can better combine different metal materials due to its different welding mechanisms, and has a higher energy density during the explosion process, which can achieve high surface area welding.

[0021] Explosive hardening technology mainly uses high-detonation-velocity explosives such as C-4, and the hardening effect is controlled by adjusting the amount of explosives and the number of loadings. Explosive welding technology mainly uses low-detonation-velocity explosives such as expanded ammonium nitrate explosives, and the welding conditions are adjusted to meet the explosion window by adjusting the amount of explosives and the spacing between the parent materials to complete the welding process. The specific parameters of the above two technical solutions are different due to the influence of material properties.

[0022] The materials of the cover plate and the base plate used in this embodiment are both steel, the cover plate material is 10CrNi3MoV, and the base plate material is 30CrMnSiNi2MoVE; the material used for the cover plate has lower strength and better toughness, and the material used for the base plate has higher strength and poorer toughness. The tensile properties of the two are as follows Figure 1 shown.

[0023] Considering that the explosion hardening process may damage the weld structure, the cover plate is first subjected to explosion hardening. Figure 2 shown.

[0024] First, 4 mm thick C-4 explosive (detonation velocity 8000 m / s, density 1.6 g / cm 3 ) to load the cover plate to produce a gradient layer. Then, expanded ammonium nitrate explosive (detonation velocity 2700m / s, density 1.05g / cm 3 ) are laminated, and the spacing between the cover plate and the base plate is 8mm.

[0025] After the cladding plate is loaded with high explosive speed, it needs to be cold rolled. After the laminate is prepared by explosive welding, it also needs to be cold rolled. Since the steel plate will bend after explosive loading, it needs to be cold rolled. The purpose of the two cold rollings is to flatten it. The purpose of the former is to facilitate subsequent welding; the purpose of the latter is to obtain a regular, flat composite steel plate, which is convenient for heat treatment and subsequent engineering applications.

[0026] After all processing is completed, heat treatment is carried out. The process is as follows: place the composite plate in a heating furnace, heat it to 650°C, keep it warm for 2 hours, cool it to 150°C with the heating furnace, take out the composite plate, and air-cool it to finally obtain a multi-scale gradient composite structure metal material.

Claims

1. A method for preparing a high-strength and high-toughness metal material with a multi-scale gradient composite structure, characterized in that: Including the preparation of microscopic gradient structure and macroscopic laminated structure; The preparation of micro gradient structure and macro laminated structure are carried out by explosion hardening and explosion welding respectively.

2. The method for preparing a high-strength and high-toughness metal material with a multi-scale gradient composite structure according to claim 1, characterized in that: The specific technical solution is: First, the cover plate is loaded with 4 mm thick C-4 explosive to produce a gradient layer; the cover plate material is 10CrNi3MoV, and the base plate material is 30CrMnSiNi2MoVE; Subsequently, expanded ammonium nitrate explosives were used for lamination, with the spacing between the cover plate and the base plate being 8 mm, and finally a multi-scale gradient composite structure high-strength and high-toughness metal material was obtained.

3. The method for preparing a high-strength and high-toughness metal material with a multi-scale gradient composite structure according to claim 2, characterized in that: The detonation velocity of C-4 explosive is 8000m / s and the density is 1.6g / cm 3 ; The detonation velocity of expanded ammonium nitrate explosive is 2700m / s and the density is 1.05g / cm 3 .

4. A multi-scale gradient composite structure high-strength and high-toughness metal material obtained by the preparation method described in any one of claims 1 to 3.

Images