EFEITO DO TEOR DE MOLIBDÊNIO NAS CURVAS DE ENDURECIMENTO POR PRECIPITAÇÃO E NA RESISTÊNCIA À OXIDAÇÃO A ALTAS TEMPERATURAS DE AÇOS MARAGING DE ULTRA ALTA RESISTÊNCIA MECÂNICA

Abstract

Five non-commercial compositions of ultra high strength maraging steels were studied within a project aiming to obtain materials with yield strength around 3 GPa. In total, five alloys with varying amounts of molybdenum were studied. The aging curves for the solubilized and cold worked conditions, were obtained. The effect of chemical composition on the high temperature oxidation resistance of the alloys was studied. Several complementary techniques for microstructural analysis were used, such as optical microscopy, X-ray diffraction and Vickers microhardness. The variation in the molybdenum content in the range from 7.5 to 15%, had a marked effect on the Ms temperature and on the oxidation resistance at high temperatures. The cold work after solubilization caused considerable effect on precipitation hardening phenomena.