Introduction to the Analysis of Various Metal Microstructures Under a Metallurgical Microscope
For many years, metallographic obligors have qualitatively drawn the microstructure characteristics of metal materials from the polished surface of metallographic specimens through microscopic observation, or evaluated the microstructure, grain size, non-metallic admixtures, and * * phase particles by comparing them with various standard images. This method is not highly systematic and involves a lot of subjectivity in evaluation. The reproducibility of the results is also unsatisfactory, and they are all measured on the two-dimensional plane of the polished surface of metallographic specimens. The measurement results are somewhat different from the true microstructure description in three-dimensional space. The emergence of modern stereology has provided people with a science of extrapolating two-dimensional images to three-dimensional space, which links the data measured on a two-dimensional plane with the theoretical microstructure, size, quantity, and distribution of metal materials in three-dimensional space. It can also establish an inherent connection between the three-dimensional structure, size, quantity, and distribution of materials and their mechanical functions, providing reliable analytical data for scientifically evaluating materials.
Due to the uneven distribution of visible microstructure and non-metallic additives in metallic materials, the determination of any parameter cannot be determined solely by measuring one or several fields of view with the human eye under a microscope. It is necessary to use accounting methods to perform many accounting tasks on a sufficient number of fields of view in order to ensure the reliability of the measurement results. Assuming that visual evaluation is solely based on human eyes under a microscope, its accuracy, consistency, and reproducibility are poor, and the measurement speed is slow, with some even being unable to proceed due to excessive workload. The image analyzer replaced human observation and accounting with electronic optics and computer skills to improve the skills of elders. It can quickly and accurately perform meaningful measurements and data processing, and has high accuracy, good reproducibility, and avoids the influence of treatment factors on metallographic evaluation results. It is also simple to operate and can directly print measurement declarations. At that time, it had become an indispensable means in quantitative metallographic analysis.
