ENGINEERING TECHNOLOGY

Metal materials with wear resistance in a wide temperature range have been improved


Metal materials with low friction and wear characteristics in a wide temperature range (room temperature to 800°C) have important application prospects and values in aerospace, nuclear energy and other advanced equipment sports and transmission systems. The new high-entropy alloy materials developed in recent years have many novel characteristics, which provide new space for the design and preparation of high-performance metal-based lubrication and wear-resistant materials, and are the hot spots and frontiers of materials science and tribology research.

Recently, the high-temperature tribology research group of the State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, has carried out systematic research on the design, preparation and performance regulation of new lubrication, wear-resistant high-entropy/medium-entropy alloys, and has made a series of progress. The results were published in Research.

“The friction and wear properties of metal materials are closely related to temperature, which will affect the mechanical properties of materials such as strength, plasticity and hardness and the friction chemical reaction at the surface interface, which makes it difficult for metal materials to have low friction coefficient and wear rate in a wide temperature range.” Cheng Jun, a researcher at the Lanzhou Institute of Chemicals, told China Science News.

Aiming at the problem of lubrication and wear resistance in wide temperature range and high temperature, the research team prepared several types of high-entropy and medium-entropy alloy lubrication and wear-resistant materials such as cobalt-chromium-nickel, cobalt-chromium-iron-nickel-aluminum, cobalt-chromium-nickel-nickel-aluminum, cobalt-chromium-nickel-nickel-titanium-boron, etc., and designed and prepared aluminum-cobalt-chromium-iron-nickel-copper reinforced high-entropy alloys for marine corrosion environments. At the same time, the mechanism of material composition and structure on the lubrication and wear resistance of high-entropy/medium-entropy alloy is revealed, and the related materials are demonstrated and applied, which solves the key technical problems of high-temperature lubrication and wear resistance of the core motion system. Recently, the research team designed and prepared a new nickel-aluminum-niobium-titanium-vanadium medium-entropy alloy with multi-level nano-heterostructure and composition fluctuation characteristics, which is a metal with the best wear resistance in the wide temperature range and has important application value as a high-temperature anti-wear material. The law and mechanism of the anti-wear friction layer formed on the surface of the alloy during the friction process were revealed.

The new high-entropy alloy material has unique heterogeneous phase structure, composition fluctuation, multi-level nano-precipitation phase and other microstructure and multi-component characteristics, showing excellent strength-plastic combination, high-temperature structural stability, friction interface self-protection, high-temperature oxidation resistance and other novel characteristics.

“Compared with traditional alloys, it has a very broad space for composition control, and some microstructure and heterogeneous phases with special properties can be obtained by replacing or increasing or decreasing elements in the high-entropy alloy system, so it provides a new space for the design and preparation of high-performance metal-based lubrication and wear-resistant materials.” Cheng Jun said.

In the field of lubrication and wear resistance, the service conditions of high-end equipment motion and transmission components are complex and harsh, often involving a wide temperature range, high load/alternating load, irradiation, micro-motion, corrosion media and other extreme coupling conditions, which has an urgent need for advanced lubrication and wear-resistant materials that cross environment and cross-temperature and other variable working conditions.

The above progress also provides new inspiration and new direction for researchers to design new high-performance metal lubrication and wear-resistant materials.

“In the future, it is hoped that new methods such as machine learning and material genetic engineering will be used to innovate the design, preparation and application research mode of lubricated and wear-resistant materials of high-entropy alloys, and explore the structure-activity relationship between composition-structure-properties of high-entropy alloys.”

Cheng Jun said that the development of related businesses in wear models and life prediction will further promote the bench assessment and industrialization application research of advanced high-entropy alloy lubrication and wear-resistant materials in the field of high-end equipment, and promote the transfer and transformation of scientific and technological achievements. (Source: Ye Manshan, China Science News)

Related paper information:https://spj.science.org/doi/10.34133/research.0160

Nano-graded heterogeneous grain structure 50 alloy and its wear resistance in wide temperature range. Photo courtesy of Lanzhou Chemical Institute.



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