Analysis of the microstructure of alloys
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Analysis of the microstructure of alloys: ensuring the quality and durability of materials

Metallographic studies help assess the structure of steels and alloys and predict their behavior under various operating conditions. Using this technique, material defects are detected. Below we will look at the main stages of metallographic analysis, its applications and importance for production.

What is metallography

Metallography is a science that studies structure of metals and alloys at the micro and macro levels using various methods of analysis.

The main types of metallographic studies:

  • Macrostructural analysis — studying the structure of the material with the naked eye or at low magnification (using a magnifying glass), which makes it possible to identify major defects and features of the material.
  • Microstructure analysis — studying the structure under a microscope, where optical and electronic methods can be used to see microscopic details and reveal more subtle characteristics of the material.

During metallographic analysis, the following are determined:

  • The shape and size of the grains that make up the metal or alloy.
  • The presence and nature of non-metallic inclusions.
  • The presence of defects such as cracks, pores and other discontinuities.
  • Type and distribution of phases in the alloy.
  • The degree of uniformity of the structure.
  • Character heat treatment.

Metallographic studies are actively used in various industries, including metallurgy, mechanical engineering, aircraft construction and others.

Stages of metallographic research

Sample preparation

The metallographic analysis process begins with sample preparation. This stage is essential for obtaining accurate and reliable results.

Sample preparation includes:

  1. Sample selection. Samples that reflect the properties of the entire material are selected for the study. These may be areas with possible defects or with the most typical structure.
  2. Sample cutting. At this stage, cutting machines or EDM units are used to accurately cut the sample with minimal damage. It is important that the sample shape is convenient for further processing and analysis.
  3. Mechanical processing. Using grinding machines and abrasive materials such as sandpaper, the sample is adjusted to the desired shape and size. Grinding should be uniform, free from scratches and other defects.
  4. Polishing. After grinding, the sample surface is polished using special polishing pastes. This makes it possible to obtain a smooth surface that will ensure good image quality during microscopic analysis.
  5. Quality control. Check whether the sample is free of defects, such as scratches or irregularities. If necessary, additional polishing is performed to achieve an ideal surface.
  6. Pickling. To identify the microstructure, the sample is chemically or electrolytically etched. This makes it possible to obtain different shades on the sample surface, corresponding to different phases and structural features of the material.

Conducting a study

The main equipment for metallographic analysis is an optical reflected light microscope. Depending on the objectives of the study, different microscopy methods can be used. Let's consider the two most common ones: research in a bright field and in a dark field.

Research in the bright field

The basic and most commonly used method of metallographic analysis. In this mode, the microscope illuminates the object of study from above, and light is reflected from the sample surface. The resulting enlarged image shows the metal structure in light colors against a dark background.

The advantages of the method:

  • Overall assessment of the structure. The bright field makes it possible to study large structural elements: grains, phase boundaries and large inclusions. And also see defects (pores, cracks and voids) that may be present in the metal structure.
  • Easy and affordable. The method is the most common and is used in most metallographic laboratories due to its simplicity and high efficiency.
  • Contrasting. The use of phase contrast or differential interference contrast helps highlight fine details of the structure, such as grain boundaries or defects that may not be visible under normal light.

Brightfield research is usually used to analyze the granular structure of metals and alloys. It is used to evaluate the quality of alloys and identify defects (cracks, pores, slag inclusions) and analyze the phase distributions and grain boundaries in materials.

Research in the dark field

They are used to identify details that are difficult to see in a bright field due to their low contrast or size. In a dark field, the microscope illuminates the sample from the side, and light is scattered from the uneven surface of the sample. This creates an image of the structure in dark tones on a light background.

The advantages of the method:

  • Identification of small details. The method makes it possible to detect minor defects and structural features, such as grain boundaries, microcracks or inclusions that are difficult to see in a bright field.
  • Better contrast for highly reflective materials. The dark field is ideal for studying highly reflective samples.
  • Difference from the bright field. The dark field helps to highlight areas of the structure that may be too small or have little contrast in the bright field.

The method is used for a detailed analysis of the structure of high-quality alloys or metals with a fine-grained structure.

The purpose of metallographic analysis

Metallographic studies make it possible to:

  • Evaluate quality of materials, identifying cracks, pores or inclusions that can significantly affect strength characteristics.
  • Identify alloy structure, evaluate their mechanical and physical properties.
  • Explore material behavior during operation, including its changes after heat treatment, cooling and other technological processes.

Metallographic studies at PZPS are mandatory in the production of the following steels:

  • Corrosion resistant steels stamps 10X17N13M3T, 12X18N9, 12X18H10T, which are actively used in the chemical, petrochemical and food industries.
  • Low-carbon steelsincluding stamps 08KP, 08PS.
  • Carbon steels U8A, U10A, 65G, 70S2HA, 70, 60S2A, which are used in the production of automotive parts and other elements that require high strength.

In addition, the company is actively using this method to work with materials such as:

Metallographic analysis is especially important when developing new grades of steels and alloys and in improving technological processes, which is an integral part of the activity NICE PZPS.

At the PZPS you can buy cold-rolled strip made of nichrome, low-carbon steel in accordance with GOST 503-81, precision alloys 27KH, 49K2FA-VI and others, as well as analogues of foreign alloys. The use of the latest equipment for metallographic analysis allows us explore at the highest level and with high accuracy and guarantee consistent quality and compliance products international standards.

Published by:
11.06.2025
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