The status and role of physical and chemical testing in the study of metallic materials

  Research content of physical and chemical testing in the study of metallic materials

  The science of metallic materials science group if the study of the interrelationship between the composition, structure and properties of metallic materials and their laws of change. Thermodynamics, kinetics, homogeneous physics, solid state chemistry, chemical physics and other basic disciplines provide the theoretical basis for the science of metallic materials. The properties of metallic materials mainly depend on the internal structure of metallic materials, and the structure of metallic materials depends on the composition of metallic materials, process parameters and other factors.

Therefore, in the study of metallic materials, the performance of metallic materials and their composition, structure, process parameters and other factors must be explored in depth to determine the reasonable composition of metallic materials and the best preparation process, processing technology and treatment process, so as to obtain the most ideal internal structure and performance to meet the requirements of use.

  In the composition study of metallic materials, the determination of the main and trace elements of metallic metal materials and inorganic non-metallic metal materials, the more commonly applied methods are atomic spectroscopy, molecular spectroscopy, electrochemical methods and conventional chemical methods; for the analysis of polymers, there is a need for such aspects as conventional elemental analysis of organic compounds, infrared spectroscopy, nuclear magnetic resonance, mass spectrometry, fluorescence spectroscopy Raman spectroscopy and so on.

For its structural study, the matrix organization and morphology are usually observed by optical microscopy; the morphology of micro-solitary holes, cracks and inclusions inside the metallic material are observed by industrial CT; the morphology of the fracture morphology, the morphology of the precipitated phases are observed by transmission electron microscopy, and the approximate composition of each phase is also given with the help of energy spectrum or wave spectrum detection; the crystal structure, orientation and stress of the second phase are identified by x-ray diffraction and selected area electron diffraction electron microprobe to link the morphology of the phase to the composition and to characterize the relative changes in the composition of the microregion; X-ray photoelectron spectroscopy, X-ray fluorescence spectroscopy, and X-ray diffraction techniques to study the crystalline and heterogeneous view of metallic materials and the valence of the elements in them; autoradiography to study the distribution of the elements and their forming phases in the matrix; thermal analysis to understand the relationship between the crystalline and amorphous structure of metallic materials.

Mass spectrometry can accurately determine the molecular weight of organic macromolecules and give molecular formulae and other institutional information; NMR spectroscopy, the combination of mass spectrometry and chromatography, the tandem of mass spectrometry itself, laser Raman spectroscopy and infrared spectroscopy to study organic structures; the combination of Fourier transform infrared spectroscopy and chromatography, known as the identification of organic structure “fingerprints”. Laser microprobe mass spectrometry can obtain the local morphology of organic elements and information on the structure of organic matter; electron spectroscopy, secondary ion mass spectrometry, pulsed laser atomic probe, OSCE, x-ray photoelectron spectroscopy, x-ray diffraction and x-ray absorption fine structure techniques, etc., to study the geometric structure of atoms at the surface and heterogeneous interface, migration and diffusion of atoms at the surface and interface, surface electronic states, heterogeneous interface chemical bonding, diffusion reflection at the heterogeneous interface and kinetics of interfacial compound formation, wettability of the heterogeneous interface, film formation mechanism and interfacial failure, etc.

  In the field of physical and chemical testing, there is still a science of physical and chemical phase analysis that studies the type, structure, composition, number, morphology, distribution state and distribution of alloying elements between phases in metallic materials, and then establishes the relationship between its alloy system and phase composition and alloy properties, and can be applied to other types of metallic materials. Of course, in the study of metallic materials, metallic material scientists are relying on scientific theories and with efficient computer tools to explore the design of metallic material structures and performance prediction, and from its chemical elemental composition to predict certain properties of high-temperature alloys, molecular design of organic macromolecules, tissue design of composite metallic materials, and linear elastic fracture mechanics based on the growth and propagation of cracks above a certain scale The method of predicting the life time based on the linear elastic fracture mechanics of crack growth and propagation above a certain scale has gained some success.

However, due to the complexity of the factors affecting the structure and properties of metallic materials and the limitations of pure theory, it is impossible to completely replace the actual physical and chemical testing research and testing work with “design” and “prediction”.

  Examples of solving specific problems in the study of metallic materials

  (1) Through the study of the type, structure, composition and content of the precipitated phases, the precipitation, dissolution and phase change laws of various high-temperature alloys during the aging process and the relationship between the composition and the relevant phases, and the relationship between each phase and its properties have been quantitatively studied. In the study of these relationships and laws, the amount of certain high-temperature alloying elements and heat treatment systems were selected and determined, and the stability of the organization, the alloying and strengthening mechanisms, and the causes of failure were discussed.

(2) for 50 boron steel embrittlement phenomenon, through the presence of boron in the steel state and distribution, the boron phase structure, composition and formation, dissolution law, boron measurement method of systematic research, put forward the Fe23 (C, B) 6 phase along the grain boundary precipitation of boron embrittlement mechanism and by higher than 9500C homolytic treatment, and combined with rapid cooling, in order to achieve the elimination or improvement of boron embrittlement measures. According to this situation, the state boron measurement method to unify, and reformulated the 50 boron steel standard.

(3) through the change of manganese addition to 93W-Ni-Fe-Co alloy mechanical properties, as well as the content and composition of tungsten particles and bonding phase in the alloy, the alloy microstructure and fracture morphology, manganese with oxygen, sulfur and other atomic distribution of the state and the type of inclusions formed, the structure, morphology, size and distribution of the alloy. A systematic study of the structure, morphology, size and distribution of the inclusions was carried out, and the mechanism of manganese purification at the grain boundary in the w-Ni-Fe-co heavy alloy was proposed, as well as the addition of one or some alloying elements that can purify the tungsten particle/bonded phase interface. To improve the bonding strength of tungsten particles with the bonding phase is an effective way to improve the plasticity and toughness of the alloy.


Physico-chemical testing is the science of establishing test methods for the composition, structure and properties of substances and providing information on their results. It provides accurate results of the composition, structure and properties of metallic materials in the study of metallic materials, and participates in the study and establishment of the interrelationships between the composition, structure and properties of metallic materials and their change laws. Therefore, physical and chemical testing is an important part of the study of metallic materials.