Intergranular Corrosion and Microstructural Evolution in a Newly Designed Al-6Mg Alloy

Abstract

In this work, the microstructure and corrosion behavior of a novel Al-6Mg alloy were investigated. The alloy was prepared by casting from pure Al and Mg+Al2Ca master alloy. The ingots were homogenized at 420 °C for 8 h, hot-extruded and cold-rolled with 20% reduction (CR20 alloy) and 50% reduction (CR50 alloy). The CR50 alloy exhibited a higher value of intergranular misorientation due to a higher cold rolling reduction ratio. The average grain sizes were 19 ± 7 μm and 17 ± 9 μm for the CR20 and CR50 alloys, respectively. An intergranular corrosion (IGC) behavior was investigated after sensitization by a nitric acid mass-loss test (ASTM G67). The mass losses of both the CR20 and CR50 alloys were similar at early periods of sensitization, however, the CR20 alloy became more susceptible to IGC as the sensitization time increased. Grain size and β phase precipitation were two critical factors influencing the IGC behavior of this alloy system.

Effects of Sc Microalloying on Microstructure and Properties of As-Extruded Al-5Mg Alloy

“…Al-Mg alloys are usually preferred as welding fillers for high-strength aluminum alloys due to their suitable weldability and strength [8][9][10]. A combination of high strength and suitable formability in non-heat treatment strengthening Al-Mg alloys can be achieved by refining the grain size and introducing precipitates in the microstructure.…”