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

Abstract

This invention provides a high-strength, high-toughness metallic material with a multi-scale gradient composite structure and its preparation method, belonging to the field of composite metallic materials technology. It includes the preparation of micro-gradient structures and macro-laminated structures; the preparation of micro-gradient structures and macro-laminated structures are carried out using explosion hardening and explosion welding methods, respectively. The method provided by this invention is expected to synergistically leverage the advantages of nano-gradient structures and layered structures in terms of reinforcement and toughening, providing a feasible and efficient structural material design strategy for addressing the high strength and high toughness requirements of materials and structures under extreme loading environments such as high strain rates.

Description

Technical Field

[0001] This invention provides a high-strength and high-toughness metallic material with a multi-scale gradient composite structure and its preparation method, belonging to the field of composite metallic materials technology. Background Technology

[0002] Metallic materials are widely used in engineering fields such as shipbuilding and national defense. However, with the development of technology, single homogeneous metal plates can no longer fully meet engineering needs. Firstly, with the increase in strength and toughness, the preparation cost of metallic materials often increases significantly. Secondly, homogeneous materials cannot solve the antagonistic effect of strength and toughness. While the strength increases, the brittleness often increases simultaneously, which restricts the application range of materials.

[0003] The main drawback of the current technology is:

[0004] (1) Limited preparation methods. Most research and applications focus only on gradient structures or laminated structures. The design in this invention fully combines the two, improving the performance of the material matrix while ensuring surface strength and hardness.

[0005] (2) Limited engineering applications. Due to the influence of gradient layer thickness, the size of metallic materials with nanogradient structures is often small. The decrease in gradient layer concentration caused by size increase cannot fully solve the problem of reduced gradient layer effect. Laminated structures can adjust material properties on a macroscopic scale, but cannot solve or reduce the antagonistic effect between material strength and toughness. Summary of the Invention

[0006] This invention aims to reduce material preparation costs while controlling the strength and toughness of materials, enabling metallic materials to meet a wider range of working conditions. The multi-scale gradient composite material is prepared using a coupled method of explosive hardening and explosive welding. On one hand, it utilizes surface gradient structures and laminated structures to resolve the strength-toughness antagonism; on the other hand, it uses the composite structure to control the materials used, replacing some high-cost metallic materials with low-cost ones, thereby achieving the goal of reducing preparation costs.

[0007] The method provided by this invention mainly consists of two parts: the first part is the preparation of micro-gradient structures, and the second part is the preparation of macro-layered structures.

[0008] The invention employs explosive hardening and explosive welding to prepare multi-scale gradient composite structure metallic materials, with the former used to prepare micro-gradient structures and the latter used to prepare macro-layered structures.

[0009] The specific technical solution is as follows:

[0010] First, a 4mm thick C-4 explosive is used to load the cladding plate to create a gradient layer; the cladding plate material is 10CrNi3MoV, and the substrate material is 30CrMnSiNi2MoVE.

[0011] Subsequently, expanded ammonium nitrate explosive was used for lamination, with a spacing of 8 mm between the two plates of the cladding and the substrate, finally resulting in a high-strength and high-toughness metal material with a multi-scale gradient composite structure.

[0012] The C-4 explosive has a detonation velocity of 8000 m / s and a density of 1.6 g / cm³. 3 The detonation velocity of expanded ammonium nitrate explosive is 2700 m / s, and its density is 1.05 g / cm³. 3 .

[0013] The method provided by this invention is expected to synergistically leverage the advantages of nanogradient structures and layered structures in terms of reinforcement and toughening, and provide a feasible and efficient structural material design strategy for the high strength and high toughness requirements of materials and structures under extreme loading environments such as high strain rates. Attached Figure Description

[0014] Figure 1 The material stress-strain curve diagram for the embodiment.

[0015] Figure 2 This is a schematic diagram of the preparation method of the multi-scale gradient composite structure material of the present invention. Detailed Implementation

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

[0017] The design method in this invention mainly consists of two parts: the first part is the preparation of micro-gradient structures, and the second part is the preparation of macro-layered structures.

[0018] The design method in this invention employs explosive hardening and explosive welding to prepare multi-scale gradient composite structure metallic materials, wherein the former is used to prepare micro-gradient structures and the latter is used to prepare macro-layered structures.

[0019] Explosive hardening technology, after extensive research, is relatively mature and primarily focuses on metallic materials, including titanium, steel, and copper. During preparation, a high-velocity (8000 m / s) explosive is attached to the material surface. The loading generated by the explosion causes high strain rate deformation on the material surface, achieving grain refinement. Influenced by the depth of load propagation, a gradient structure from nanocrystalline to coarse-grained can be achieved within the material. Grain refinement significantly improves the material's strength, hardness, corrosion resistance, and other properties, while the resulting gradient structure effectively reduces the antagonistic effect between strength and toughness. Compared to other preparation methods, explosive hardening can increase the thickness of the gradient layer, making it more valuable for engineering applications.

[0020] Because different metal materials have certain performance differences, traditional welding methods often affect material properties and may even lead to ineffective welding. Explosive welding, due to its different welding mechanism, can better bond different metal materials and has a high energy density during the explosion process, enabling high surface area welding. Therefore, it is widely used in engineering manufacturing.

[0021] Explosive hardening technology primarily utilizes high-velocity explosives such as C-4, controlling the hardening effect by adjusting the charge and the number of loading cycles. Explosive welding technology mainly utilizes low-velocity explosives such as expanded ammonium nitrate, adjusting the charge and the spacing between the base materials to ensure the welding conditions meet the explosion window, thus completing the welding process. The specific parameters of these two technologies differ due to the influence of material properties.

[0022] In this embodiment, both the cladding plate and the substrate are made of steel. The cladding plate is made of 10CrNi3MoV, and the substrate is made of 30CrMnSiNi2MoVE. The cladding plate material has lower strength but better toughness, while the substrate material has higher strength but poorer toughness. Their tensile properties are as follows: Figure 1 As shown.

[0023] Considering that the explosive hardening process may damage the weld structure, the cladding plate is first subjected to explosive hardening. The specific design scheme is as follows: Figure 2 As shown.

[0024] First, a 4mm thick layer of C-4 explosive (detonation velocity 8000m / s, density 1.6g / cm³) was used. 3 A gradient layer is created by loading the cladding plate. Subsequently, expanded ammonium nitrate explosive (detonation velocity 2700 m / s, density 1.05 g / cm³) is used. 3 The two plates are laminated together, with a spacing of 8mm between the cover plate and the substrate.

[0025] After the cladding plate is subjected to high-velocity explosive loading, it needs to be cold-rolled. Similarly, after explosive welding to prepare the laminate, it also needs to be cold-rolled. Because the steel plate will bend after explosive loading, cold rolling is necessary. The purpose of both cold rolling processes is to flatten the plate; the former facilitates subsequent welding, while the latter aims to obtain a regular, flat composite steel plate for easier heat treatment and subsequent engineering applications.

[0026] After all processing is completed, heat treatment is performed. The process is as follows: the composite plate is placed in a heating furnace, heated to 650°C, held for 2 hours, and then cooled to 150°C with the heating furnace. The composite plate is then removed and air-cooled to obtain a multi-scale gradient composite structure metal material.

Claims

1. A method for preparing high-strength and high-toughness metallic materials with multi-scale gradient composite structures, characterized in that, This includes the preparation of micro-gradient structures and the preparation of macro-layered structures; Micro-gradient structures and macro-laminated structures are prepared by explosive hardening and explosive welding, respectively. The specific technical solution is as follows: First, a 4mm thick layer of C-4 explosive is applied to the cladding plate to create a gradient layer; the detonation velocity of C-4 explosive is 8000 m / s, and its density is 1.6 g / cm³. 3 The cladding material is 10CrNi3MoV, and the substrate material is 30CrMnSiNi2MoVE. During preparation, a high-velocity explosive is attached to the surface of the material. The loading generated by the explosion of the explosive causes the surface of the material to undergo high strain rate deformation, thereby achieving the effect of grain refinement. Due to the influence of the loading propagation depth, a gradient structure from nanocrystals to coarse grains is achieved inside the material. After the cladding is subjected to high-velocity loading, it needs to be cold-rolled. Subsequently, expanded ammonium nitrate explosive was used for lamination. The expanded ammonium nitrate explosive had a detonation velocity of 2700 m / s and a density of 1.05 g / cm³. 3 The gap between the two plates of the cladding and the substrate is 8mm. After the laminate is prepared by explosive welding, the laminate must also be cold rolled. After all processing is completed, heat treatment is performed. The process is as follows: the composite plate is placed in a heating furnace, heated to 650°C, held for 2 hours, and then cooled to 150°C with the heating furnace. The composite plate is then removed and air-cooled to obtain a high-strength and high-toughness metal material with a multi-scale gradient composite structure.

2. A high-strength and high-toughness metallic material with a multi-scale gradient composite structure, obtained by the preparation method described in claim 1.

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