Estudo da estabilidade da austenita revertida em um aço maraging 18%Ni grau 300

Abstract

Maraging steels have low carbon and have a body-centered cubic martensitic (BCC) crystalline structure. These steels offer a unique combination of high mechanical strength and good fracture toughness. In this work, a study in situ synchrotron radiation in seeking to assess the stability of reversed austenite in maraging steel grade 18%Ni 300. A flat bar sample with standard dimensions was solution treated at 840°C for 1 h and cooled in air. Then heated at a rate of 10°C per second to 630°C, keeping this temperature for 12 minutes. Subsequent to this treatment the sample was cooled to room temperature at a rate of 15°C per second. Measurements of synchrotron radiation with a wavelength (λ = 1.0332 Å) were performed at each stage of the heating cycle. The volume fraction of martensite and austenite phases present in each stage of the thermal cycle were calculated using the method of direct comparison and through the integrated area of the peak for the phases. The mechanical stability of the reverted austenite under external load was studied using synchrotron radiation-situ.