Ways Of Strengthening Metal Material

As we all know, the application of metal materials involves many fields of life and production - industry, agriculture, aviation and so on. The most common processing technologies of metal materials are casting, pressure processing and welding. The forming materials are inspected by appropriate detection methods for their defects in structure and performance, and then processed to meet the requirements of use and performance. The first step in manufacturing any product is material selection. The most common failure modes of materials are wear, corrosion and fracture. Failure usually comes from the surface. In order to improve the strength, hardness, rigidity, wear resistance, corrosion resistance and other properties of metal materials, it is generally necessary to modify and strengthen the metal surface.

1 Metal Alloying

Alloying is an effective measure to strengthen metal surface and improve its comprehensive properties. There are two correlations between dissolution and reaction among different metal components

The different interactions between components lead to the formation of solid solutions, compounds and mechanical mixtures. The surface atomic and crystal structures of two or more components are adjusted or changed to some extent by diffusion, permeation, physical adsorption and chemical changes.

1.1 Plasticization

Plasticization is a process of microalloying by adding alloying elements such as Fe, B, Al and controlling the amount of them to less than 1%. Adding appropriate plasticizing elements to NiAl single crystal can increase its elongation at room temperature significantly; adding grain boundary toughening elements such as B can promote the segregation of alloy elements to grain boundary, and the failure mode changes from intragranular fracture to transgranular fracture, thus improving room temperature plasticization; adding active elements such as La can hinder crack propagation and increase material strength, reduce surface tension and refine grain size. Strengthen metals while improving their toughness.

1.2 Solid Solution

A solid solution with metallic properties is formed between alloy components by dissolution without reaction. If the two components have the same structure and are close to each other on the periodic table of elements,

The former is infinite solid solution, infinite intersolubility between components, lattice distortion and enhancement of alloy properties; the latter is finite solid solution, but through its surface and internal line defects, solid solution elements are easy to pin defects, resulting in solid solution strengthening effect and strength. The hardness is improved obviously.

1.3 Surface Atomic Diffusion

Diffusion refers to the dynamic movement of atoms, ions, molecules and atomic groups on metal surface through thermal action. Metal surface diffusion includes the movement of parallel surface and vertical surface. Atom vibrates at its equilibrium position when heated. The higher the temperature, the easier the excitation of the atom and the larger the amplitude. When the energy of atom exceeds its transition barrier, it will depart from its original position. If the motion is unbalanced, more and more surface atoms become active atoms, and the chemical bonds between atoms break and produce the trend of surface movement; or because of internal structural reasons, the atoms have higher energy and unstable system when there are internal defects such as holes, step vacancies, interstitial atoms, dislocations, stacking faults and so on in places with abrupt size change, usually when the temperature is not high, the atoms can be used. In order to obtain enough activation energy and promote atom diffusion. The diffusion mechanism is used to restructure the surface structure and strengthen the metal itself.

1.4 Preparation of Multiphase Alloys

It is one of the common methods to improve the comprehensive properties of metal materials to prepare multiphase alloys by adding second phase to metal materials. By adding to the tough matrix

The addition of brittle second phase reduces its toughness, increases its hardness and strength, and adds tough second phase softening matrix to the brittle matrix to achieve the purpose of strengthening. At present, the high-temperature oxidation resistance and corrosion resistance of metal materials are relatively weak. Generally, the high-temperature and low-temperature activity of metal materials can be reduced by adding composite components such as ceramic matrix.

2. Surface Finishing Technology-Weill Ultrasound Mirror Processing

Will's ultrasonic mirror processing technology utilizes the cold plasticity of metal materials at room temperature to carry out high frequency and high focus energy impact on the surface of parts tens of thousands of times per second, so as to extend the processing trace such as turning, grinding and milling to achieve mirror effect. This is a new processing technology, which does not remove materials, does not affect the dimensional accuracy and position tolerance of the workpiece, and greatly improves the performance of the parts. The results are as follows:

1. Without turnaround process, the surface roughness of parts can directly reach below Ra0.2.

2. The hardness, wear resistance and other comprehensive properties of the parts are significantly improved, and the service life is more than twice as long as that of the traditional process.