Structure-Phase Composition and Properties of Mechanically Alloyed High-Nitrogen Powder Steels

摘要

The structure and properties of the Fe-21% Cr-N and Fe-18% Cr-7% Ni-0.8% Mn-0.5% C-N powder systems mechanically alloyed in nitrogen atmosphere and steels sintered from the powders in dissociated ammonia at t = 1170°C have been investigated. The thermodynamic calculations of the phase compositions of the steels are carried on the basis of searching the Gibbs integral energy minimum for the system. In comparing the obtained experimental data with the results of thermodynamic calculations for the Fe-Cr-C-N and Fe-Cr-N systems, it is found that the equilibrium phase composition is not reached. The resulted steels contain increased nitrogen quantity (1.6 to 2.1%) distributed in austenite and/or nitrides. The steels have high strength, wear and corrosion resistance.