Metallography plays a fundamental role in quality control and the development of new materials. At the St. Petersburg Precision Alloys Plant (PZPS), metallographic examinations are an integral part of the production process. Thanks to modern equipment and highly qualified specialists, the company provides accurate analysis of the structure of steels and alloys, which directly affects the quality, reliability and durability of its products.
What is metallography and why is it needed?
Metallography is a branch of metal science that studies the structure of metals and alloys using microscopic methods. It allows you to analyze the microstructural features of materials, such as:
- grain size and shape;
- presence of phases;
- defects and heterogeneity;
- other characteristics affecting mechanical and physical properties.
The importance of metallography in materials science can hardly be overestimated. It allows you to establish a relationship between the structure and properties of materials, which is important for optimizing the production and processing of steels and alloys, as well as for predicting the behavior of materials under various operating conditions.
At PZPS, metallography is used for:
- analysis of the macro- and microstructure of steels and alloys;
- quality control of finished products;
- assessing the impact of heat treatment.
Modern metallographic research is unthinkable without precise and sensitive microscopes. Each type of such equipment has its own unique features, advantages and applications.
Microscopes are a key tool for metallography
Microscopes play a critical role in metallographic research by providing high-resolution images of microstructure. With their help, it is possible to study in detail the morphology of grains, phase distribution, the presence of defects and other important parameters that determine the properties of materials.
Optical microscopes
An optical microscope uses visible light to create a magnified image of an object. It allows microstructure to be observed through reflected light.
Operating principle
- Light passes through the sample and then through a lens system that magnifies the image.
- The microscope lens collects light from the sample and forms a primary magnified image, which is then further magnified by the eyepiece.
- As a result, the observer sees a detailed image of the structure of the sample.
Key Features
Optical microscopes are actively used at PZPS, since they allow you to quickly and efficiently solve a number of problems:
- Determine grain size, which allows you to evaluate the strength, ductility and other mechanical properties of alloys.
- Phase identification — different phases in the material have different optical properties, which makes it possible to analyze their distribution.
- Microstructural defect analysis — with appropriate magnification, it is easy to detect and study defects such as cracks, voids and inclusions.
Advantages
- Ease of use — optical microscopes are relatively easy to use and do not require complex sample preparation.
- Availability - They are widely available and affordable, making them a popular choice for many laboratories.
Restrictions
- Permission — optical microscopes are limited in resolution due to light diffraction. The maximum magnification is usually about 2 thousand times, which may not be enough to study very small structures.
- Depth of field - Limited depth of field can make it difficult to obtain clear images of layers located at different depths in the sample.
Working with optical microscopes requires preliminary preparation of sections and etching of the surface: the plane under study must be smooth, without scratches, marks, pits and dirt. It is also worth considering that using such equipment it is impossible to analyze structures smaller than 1 micrometer.
Electron microscopes: transmission and scanning
Electron microscopes make it possible to study materials at the nanometer level, which opens up new horizons in metallographic analysis.
Advantages
- High resolution — images with a resolution of several nanometers make electron microscopes indispensable for studying fine structures and defects.
- High depth of field — allows you to obtain clear images of objects with uneven surfaces.
- Wide range of applications, including chemical analysis — used in various fields of science and technology, including materials science, solid state physics, chemistry, biology and medicine.
Restrictions
- Difficulty in sample preparation — for examination in an electron microscope, samples must be carefully prepared, which requires special skills and equipment.
- Limitations on sample size and shape — only samples that can be placed in a vacuum chamber can be examined.
- High cost of equipment and maintenance — this limits the availability of electron microscopes for some laboratories.
Key Features
- Investigation of fine structures and defects — makes electron microscopes indispensable for studying the crystal structure, microstructure and defects in metals, semiconductors and other materials.
- Point analysis of chemical composition and structure — various detectors with which electron microscopes are equipped make it possible to accurately determine the chemical composition, distribution and concentration of elements in the samples under study.
Transmission electron microscopes (TEM)
A transmission electron microscope is an instrument for producing images of ultra-thin objects using a beam of electrons passed through a sample. In TEM, electrons pass through a thin film of a sample, interacting with its atoms and changing their trajectory. The detector catches the transmitted electrons and an image is formed based on their distribution.
FEM capabilities:
- crystal structure analysis at the atomic level;
- dislocation detection, vacancies, micropores and other defects;
- film thickness measurement and layers in multilayer materials.
TEM produces high-resolution images, making it an indispensable tool for studying the structure, defects and thin layers of materials. It is widely used in materials science, solid state physics, chemistry and biology.
Scanning electron microscopes (SEM)
Scanning electron microscope is a device that creates an image of an object by scanning its surface with a beam of electrons.
Application of SEM:
- relief research high precision surfaces;
- chemical analysis points and zones on the surface;
- identification of microcracks and inclusions in metal.
In an SEM, an electron beam is focused on the surface of a sample and moves along it in a raster pattern. When electrons interact with sample atoms, secondary electrons are generated, which are captured by the detector and converted into an image.
Atomic force microscopes (AFM)
The atomic force microscope is a unique tool for analyzing surfaces at the atomic level without the need to create a vacuum. Allows you to obtain images with high spatial resolution. The microscope uses a cantilever (arm) with a sharp probe that "probes" the surface of the material. The laser tracks the probe's deviations and builds a three-dimensional model of the terrain.
Operating principle
- The probe is brought to the sample surface at a distance of several nanometers.
- Interaction forces arise between the probe and the surface, which can be either attractive or repulsive forces.
- The resulting forces are measured by certain methods, for example, using a laser beam reflected from a cantilever.
- Based on the obtained measurements, a three-dimensional model of the surface relief is constructed.
Main features of AFM
- Study of surface topography — AFM allows you to obtain detailed images of a surface with high resolution, which helps to study surface topography, identify defects, irregularities and other features. Images can be presented in the form of three-dimensional graphs, which clearly show the surface relief.
- Measuring mechanical properties at the micro and nano level — including measurement of rigidity, adhesion, elasticity, friction and more. Measuring properties is especially important when studying materials after heat treatment, development of new alloys and steels and optimization of technological processes.
Advantages
- High spatial resolution, which makes it possible to analyze structures of several nanometers.
- Ability to study surfaces in various modes: contact, semi-contact and non-contact.
- Ability to measure mechanical properties surfaces.
- No special sample preparation, allowing you to examine the surface in its natural state.
Restrictions
- Complexity and high cost equipment.
- Limited scanning area, which depends on the size of the cantilever and the sample.
- Influence of external factors (temperature, humidity and vibration) on image quality.
- Difficulty of interpretation received data, which requires highly qualified operator.
PZPS products: alloys tested under a microscope
Strict metallographic inspection is carried out at the PZPS using reflected light optical microscopes. This allows you to quickly identify deviations and ensure stability of characteristics products.
Assortment of cold rolled strips from:
- precision soft magnetic alloys grades 49K2FA-VI, 27KH, 50N, 50NP, 79NM, 80NM, 81NMA;
- precision alloys for elastic elements of grades 40KHNM, 36NHTY, 17ХНГТ;
- precision alloys with high electrical resistance grades Х15У5, Х23У5, Х23У5Т, Х15Н60-Н, Х20Н80-Н;
- corrosion-resistant steel grades 12Х18Н9, 12Х18Н10Т, 10Х17Н13М3Т;
- heat-resistant alloys grades 20Х13 And ХН78Т.
This range of products covers a wide range of needs in instrumentation, electronics, aviation, petrochemicals and other industries. For questions regarding cooperation, please call +7 (812) 740-76-87 or leave application on the website. Our specialists will select precision alloys or special steels for any technical task.
