Improvement of chemical composition, structure and mechanical properties of heat-resistant chromium-nickel alloy

Abstract

View the article online for updates and enhancements. Related contentForming patterns and mechanical properties of austenitic chromium-nickel steel due to strain aging N V Kamyshanchenko, V V Krasilnikov, I S Nikulin et al. A thermodynamic analysis of a multicomponent system of the Cr-Ni alloy (Cr-32Ni-1,5W-0,25V-0,5Ti) with small additions of refractory metals was carried out. The microstructure and phase composition of the base alloy (I) and alloy with additional alloying (II) were studied. The effect of additives on the mechanical properties of the Cr-Ni alloy at 20, 900 and 1080 °С was shown. The microstructure of alloys I and II was studied in the fracture zone of samples after tensile tests at different temperatures. We studied the effect of small additives on the microstructure of alloys and changes in the morphology of the structural components (phases) as a function of temperature and degree of deformation. IntroductionDevelopment and improvement of hot-strength and heat-resistant materials is one of the key issues of metal science. The use of new modern materials is a necessary condition for achieving the required tactical, technical and operational characteristics of material for space application. Extreme operating conditions of products are forced to tighten the requirements to the level and stability of the properties for materials being developed [1]. High-temperature chromium-based alloys due to significant high-temperature strength at temperatures above 1000 °C, thermal stability and high corrosion resistance are promising substitutes for nickel alloys for aerospace and power engineering application [2].At present, high-temperature Сr-based alloys has a limited employing in industry. The known alloy Cr-(31-35) Ni (1-3) W-(0.1-0.4) V-(0.05-0.3) Ti mass. % used to manufacture fuel decomposition chambers and nozzle of satellite's thrusters that operate in an impulse power setting.However, from the point of view of the ongoing update of the requirements to mechanical properties and high-temperature strength, particularly, the potential of the existing alloy is almost exhausted and its further improvement is required.The grain boundaries are the "weakest" elements of the structure in polycrystalline alloys in terms of creep resistance and a tendency to embrittlement. It is known that the properties of grain boundaries depend on their chemical composition that differs from the average chemical composition of the alloy due to segregation phenomenon [3]. Low-alloying is a well-known hardening method at which the structure and properties of alloys are changed due to local formation on borders of grains and sub-grains of the strengthening phases with limited solubility in α-γ solid solutions of alloy. The specific state of