An Investigation on the Effects of Boronizing Process on Microstructure and Microhardness of NiTi Alloy Produced by P/M Technique

Abstract

In this study, samples were produced by the powder metallurgy method from pre-alloyed NiTi powders. The pressing process was carried out at 300 degrees C temperature under 700MPa pressure. The pressed samples were sintered at 1200 degrees C for 120 minutes in high temperature resistant Quartz glass tube under a high purity Argon atmosphere. Sintered samples were boronized at 900 degrees C and 1000 degrees C for 6 and 12 hours. FESEM, EDS, MAP and Optical Microscope analyzes were carried out for the microstructure analysis. In addition, microhardness measurements and microhardness images were taken for hardness measurements. The surface hardness of the samples increased in all applied boronizing parameters. The largest layer thickness and highest hardness value were obtained at 1000 degrees C for 12 hours as 50 mu m and 2074.9 HV respectively.