Influence of Ageing Time and Different Ni wt.% on Triplex Steel

Abstract

This paper presents a study of three types of Triples steel, where containing 16 to 28 wt.% manganese, 0.8 to 0.89 wt.% Carbon, 9.9 to 11.21 wt.% Aluminum, and with different Nickel content. We investigated the aging effect on properties of Triplex steel by using an optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). The used temperature in the ageing process is 550°C and we take three different times in that process (1min, 1hr, and 5hrs). The microstructure shows one austenite phase of an as-rolled sample without Ni and shows two austenite phases of an as-rolled sample with Ni content. The k-carbide, intermetallic phase (Ni3Al) and annealing twins formation will appear after adding Ni element. Furthermore, those phases will be increased with aging time. X-ray diffraction shows a competitive formation between the k-carbides and intermetallic phase formation during the aging time. It's confirmed that K-carbides will be formed first after that intermetallic phase, where k-carbides were formed at low temperature. Finally, we can conclude from these results that adding Ni in Triplex steel improves the ductility with 1hr aging time.