Double-Glow Plasma Surface Alloying of BTi-62421S Alloys: Regulation of Microstructure Properties

Abstract

In order to meet the design requirements of lightweight artillery and adopt the method of double-glow plasma nitriding to solve the problem of low hardness and poor abrasion resistance of Ti alloy, the BTi-62421S high-performance titanium (Ti) alloy was selected as the experimental material to replace gun steel. To study the effect of different nitrogen (N) concentrations on the heat resistance scouring performance of BTi-62421S high-performance Ti alloy and investigate the influence of alloying elements on the heat resistance scouring performance under the same parameters compared with the commonly used TC4 Ti alloy, argon was used as the protective gas by continuously increasing the N concentration (Ar/N2 = 1:1, 1:2, 1:3). It was found that the honeycomb structure on the surface of the sample and the thickness of the coating increased continuously, reaching a thickness of 15 μm, while the depth of the nitride particles extending from the coating to the substrate also increased, reaching a maximum depth of 26 μm. The orientation of TiN changed from 37° to 62°. The hardness of the coating showed a negative correlation with the coefficient of frictional abrasion, which significantly improved the heat-resistant scouring performance of BTi-62421S high-performance Ti alloy.