Nickel net chain structure nickel-aluminum composite material and preparation process

Abstract

The invention relates to a method for preparing a nickel-aluminum net chain structure material by compounding multi-branch nickel powder and spherical aluminum powder. High-specific-surface-area multi-branch-shaped reduced nickel powder is adopted as a framework material, and a spatial network is formed by utilizing the vertical crossing characteristic of branches of the framework material; and the spherical aluminum powder plastically deforms under high pressure and fills network gaps, so that a concrete-like structure of a nickel framework-aluminum matrix is formed. According to the structure, the interface bonding strength is improved through nickel branch mechanical interlocking, meanwhile, aluminum phase plastic flow coordinates stress concentration, and the toughness and strength of the composite material are remarkably improved. The preparation process adopts gradient pressing, and is compatible with cold spraying additive manufacturing or tablet press pressurization and other technologies. The material is suitable for the fields of nickel-aluminum-based active composite materials for welding, shaped charge liners and the like.

Description

Technical Field

[0001] This invention belongs to the field of metal matrix composite technology, specifically relating to the innovative design and efficient preparation process of a high-strength and tough nickel-aluminum mesh structure material, which is particularly suitable for preparing nickel-aluminum based active composite materials and can be used for welding, propellant liner, etc. Background Technology

[0002] Analysis of existing technological deficiencies: 1. Weak interfacial bonding: Traditional nickel-aluminum composite materials are made by mixing and pressing spherical powders, and the particles are only physically bonded at the interface, resulting in low interfacial bonding strength. 2. Insufficient ductility and toughness: Significant tendency towards brittle fracture, prone to delamination failure under high pressure; 3. Structural limitations: Although layered rolled composites (such as CN119753427A) improve bonding strength, they exhibit significant anisotropy, making it difficult to achieve three-dimensional uniform reinforcement. 4. Areas for technological breakthroughs: A continuous reinforcement network is constructed by replacing mechanical mixing with dendritic nickel powder topological interlocking; Aluminum powder is used to fill micro-gaps through plastic flow, forming a stress buffer layer; Cold isostatic pressing reduces porosity and suppresses interfacial cracks. Summary of the Invention

[0003] Core innovation points: 1. Mesh Chain Structure Design: A three-dimensional interpenetrating mesh chain structure is formed by mixing and pressing multi-branched nickel powder (high hardness) and spherical aluminum powder (low hardness); 2. Nickel framework: Multiple branches of nickel powder intersect to form a three-dimensional interpenetrating network, and the contact points of the branches achieve interlocking bonding through mechanical interlocking; 3. Aluminum filler phase: Spherical aluminum powder deforms into polyhedra under high pressure, with a filling rate >95%; 4. Synergistic reinforcement and toughening mechanism: The nickel skeleton bears the main load, while the aluminum phase absorbs impact energy through plastic deformation.

[0004] Technological Innovation: Cold isostatic pressing: 100~150 MPa pre-compression → 300~800 MPa gradient compression, the partial pressure gradient eliminates pores (final porosity <5%). The greater the pressure gradient and the higher the pressure, the lower the porosity. Detailed Implementation

[0005] Example 1: Preparation of oxide scale by ball milling.

[0006] Raw material processing: Under the protective atmosphere of inert gases such as argon, spherical aluminum powder (D... 50(1~40 μm, oxygen content <0.5wt%) is ball-milled and mixed with Y2O3 and other nanoparticles to remove the oxide scale on the surface of aluminum powder and improve reactivity. Nickel powder has a branched structure and is not suitable for ball milling to remove the oxide scale, as this may cause the branches to break. In addition, the oxide scale of nickel powder is very thin, and it can still react with aluminum powder even without descaling.

[0007] 1. Initial cold isostatic pressing: Hold at 100~150 MPa for 5 min, preform density ≥85%; 2. Gradient pressing: Apply pressure at different steps from 10 to 100 MPa / min to 300 to 800 MPa, and hold for 3 to 20 minutes each, so that the final green body has a density >95%; Example 2: Cold Spray Additive Manufacturing 1. Mix pure dendritic nickel powder with aluminum powder (nickel-aluminum mass ratio 0.72~6.53, corresponding to a nickel-aluminum molar ratio of 1:3~3:1) and feed the mixture into a cold spraying equipment; 2. Carrier gas pressure 4 MPa, temperature 500℃, deposition rate 50 g / min.

Claims

1. A nickel-aluminum composite material with a nickel mesh structure, characterized in that: A three-dimensional interpenetrating network structure is formed by mixing and pressing multi-branched nickel powder (high hardness) and spherical aluminum powder (low hardness); the branches of the multi-branched nickel powder are mechanically interlocked to form a skeleton, and the spherical aluminum powder plastically fills the gaps in the skeleton; the aspect ratio of the branched nickel powder is ≥5, and the particle size of the aluminum powder is ≤50% of the minimum gap between the nickel powder branches.

2. The composite material according to claim 1, characterized in that: The dendritic nickel powder is in a reduced state, with a specific surface area of ​​1.5~3.0 m² / g, a branch length of 10~200 μm, and an aspect ratio ≥5, ensuring that the branches interlock to form a continuous network (when the aspect ratio of the dendritic nickel powder is <5, it is difficult to form a stable continuous framework); the aluminum powder is atomized spherical powder with an oxygen content ≤0.5% and a particle size of 1~40 μm. To make it easier for the aluminum powder to be squeezed into the gaps between the nickel powder branches, the ratio of the aluminum powder diameter to the nickel powder branch length is limited to less than 1:

5.

3. A preparation process for the composite material according to claim 1, characterized in that... Includes the following steps: Mixing: Ball milling and mixing powder under an inert atmosphere for 1-4 hours, with a nickel-aluminum mass ratio of 0.72-6.53, corresponding to a nickel-aluminum molar ratio of 1:3-3:1; Pressing: Pre-pressing (cold isostatic pressing 100~150MPa, holding pressure for 3~20min) + cold isostatic pressing gradient pressing (300~800 MPa gradient pressing, holding pressure for 3~20min per pressure gradient). It is particularly important to note that, to ensure the aluminum powder fully fills the gaps and improves density and interfacial bonding strength, the final pressure of the gradient pressing is set to 300~800 MPa. When the final pressure of the gradient pressing is <300 MPa, the porosity is too high, the material density is too low, and the plasticity and toughness are compromised.

4. The preparation process according to claim 3, characterized in that: Before pressing, the mixed powder is subjected to cold isostatic pressing pretreatment (pressure 100~150 MPa), and a settling tank structure is preset in the mold to enhance the positioning of the powder.