A A Shatsov

doi:10.19080/JOJMS.2024.09.555752

Short Communication

The Prospects in the Field of Powder Materials and Low-Carbon Martensitic Steels

A A Shatsov*

Perm National Research Polytechnic University, Perm, Russia

Submitted: August 02, 2024; Published: October 10, 2024

*Corresponding author: A A Shatsov, Perm National Research Polytechnic University, Perm, Russia

How to cite this article: A Shatsov. The Prospects in the Field of Powder Materials and Low-Carbon Martensitic Steels. JOJ Material Sci. 2024; 9(1): 555752. DOI: 10.19080/JOJMS.2024.09.555752

Keywords: Powder materials; Low-carbon martensitic steels; Pure carbonyl iron

Short Communication

Powder steels and alloys (PS) and low-carbon martensitic steels (LCMS) are well-known materials with far from exhausted potential for realizing their properties. The two main differences of PS from cast and deformed materials are porosity and concentration inhomogeneity. It is widely accepted that porosity reduces mechanical properties, but for highly pure carbonyl iron, there is no strict monotonic decrease in K1c in the intervals of 4-7%. The result obtained was explained by the dazing of the crack in the pores and subsequent bending of its front [1,2]. This approach is possible only for dispersed pores in pure materials. The transfer of impurities from the surface of pores to the surface of grains in samples during the formation of an impermeable structure explains the dependence of fracture toughness on porosity with a minimum when forming an impermeable porous structure.

The wide possibilities of using powder antifriction materials are presented by the introduction of lubricants into the pores. In this case, there is a competition between the lubricant and the matrix in terms of the filling of pores and maintaining their shape. The developed composite materials with a porous structure showed the possibility of creating materials with improved anti-friction properties and wear resistance, which makes them promising for a wide range of industrial applications [2,3].

It is evident that the use of poly component cokes, which may contain strengthening phases such as titanium carbide or hard alloys, expands the application of PMIs (powder metallurgical materials). A simple way of creating carbosteels and ferrotics is by infiltrating copper alloys into composites [4]. The best combinations of mechanical and tribotechnical characteristics are achieved when copper-infiltrated steel provides deformation during loading. The Trip-effect is due to relatively low concentration inhomogeneity, as sintering takes place in the presence of a liquid phase based on copper [4].

The specified concentration non-uniformity can be obtained in nickel steels using bidisperse powders. The idea behind this approach is to divide the regions with increased and decreased content of nickel and carbon. During cooling, the metastable austenite is formed in the regions with increased nickel and carbon content, while martensite is formed in regions with lower concentration of these elements. The composition and cooling rate should prevent the formation of other phases in the steel. The carbon segregation observed during Bainite transformation, often called the stasis, can be considered as a concentration non-uniform steel, but the advantages of powder TRIP steels are obvious since their strength exceeds 2000 MPa with a combination of impact viscosity of more than 1.2 MJ/m2, fracture toughness K1C= 63 MPam3/2 and hardness of 50 HRC. By varying the composition and casting (homogenization) technology, the fracture toughness can be increased to K1c= 88 MPam3/2, but the strength then decreases to 1500-1600 MPa.

It should be noted that the aforementioned mechanical properties were obtained using traditional powder metallurgy technology without the use of cyclic and dynamic loads or particularly pure materials [5]. The tri-effect is also possible in composite materials based on infiltrated copper steels [6]. The most important direction in metallurgy is the production of precision alloys and parts from them. The new approach to creating powder alloys is to obtain billets that are not inferior in uniformity of nickel and chromium distribution to industrial alloys.

The required homogeneity can be obtained using dispersive carbonyl powders and high-temperature long-term sintering regimes (1300°C, 5 hours). The subsequent thermal treatment regimes are not much different from traditional analogs [7]. Significantly higher values of magnetic permeability for electrical steel and sendust can be obtained using polycomponent active iron, ferroalloy powders, and the introduction of additions that form a liquid phase during sintering. It is important to note that sendust is the only alloy studied where the concentration heterogeneity of aluminum and silicon increased sharply with an increase in the duration of sintering. Therefore, elements were added to expand the regions of the liquid phase’s existence. As a result, density increased during short-term regimes, and concentration heterogeneity changed weakly. The maximum magnetic permeability of steel was 8000-10000 Gauss/Oersted, sendust was 11000-13500 Gauss/Oersted. A pre-heat treatment of the scrap in hydrogen was an essential operation [8].

Materials based on Fe-Cr-Co(Mo) system are most interesting in the case of use of the rib concentration of the alloying elements because they have the highest temperature of the start of alphaphase formation and alloys with high cobalt content (23Co, 30Cr). Both can be obtained by sintering in the presence of a liquid phase formed by additives that form eutectics. Further improvement of rib alloys properties is possible by adding Sm-Co magnet powder, but the optimal amount and composition of samarium-cobalt alloy is not yet clear. High cobalt alloys can be significantly improved by adding small amounts of ferroboron, which increases the amount of liquid phase during sintering and also hinders the formation of sigma phase. The result is that the cobalt content can be increased by 4% with an increase in magnetic properties [9].

Low-carbon martensitic steels (LCMS) are of great practical interest in the field of modern construction materials. The structural inheritance phenomenon has been observed in LCMS when they are alloyed with strong carbide-forming elements, which manifests in the preservation of the re-crystallized structure during heating in the intercritical temperature range and in the austenitic region [10]. As a result, steels with strengths of 750- 1500MPa and impact toughness KCV of 3-0.9MJ/m² have been created based on the structural inheritance. Thus, simple and inexpensive technologies and materials have been proposed based on new approaches to achieve higher performance characteristics for parts made from precision, tribotechnical, and construction materials.