Corrosion, microstructural and mechanical characteristics of advanced aluminum-magnesium alloys with scandium and zirconium additions at elevated temperatures

Abstract

Aluminum alloys are very economical and attractive for a wide variety of applications because of their lightweight, ease of fabrication, optimum combination of physical properties, improved mechanical properties and superior corrosion resistance. Scandium, with its unique strength and weight saving characteristics has been introduced as a potential alloying element in several aluminum alloys. Sc addition brings about dramatic improvements in the mechanical and physical characteristics of aluminum alloys. Scandium provides highest increase in strength per atomic percent of any alloying element has created a great deal of interest in the aluminum industry. To explore the high performance capabilities, one of the most vital parameter---corrosion which affects the service performance has been left unaddressed by researchers and needed to be investigated to determine the application potential of these alloys. The work conducted involved the corrosion studies of Al-Mg-Sc-Zr alloys in corrosive environment on which relatively little work has been done. Al-Mg-Sc-Zr alloys containing scandium ranging from 0-0.9 wt% Sc and 0.14 wt% Zr were used for corrosion studies in 3.5 wt% NaCl. Corrosion studies included weight loss, electrochemical studies, impingement test, velocity test and elevated temperature polarization studies. Micro structural studies include SEM and EDS analysis to identify the constituents. Mechanical properties of the alloys were determined by conducting tensile tests at room temperature and elevated temperatures.