Microstructure-corrosion interrelations in new low-lead and lead-free brass alloys

• Main Author: Stålnacke, Emil
• Format: Others
• Language: English
• Published: KTH, Materialvetenskap 2017
• Subjects: Brass; dezincification; annealing; detrimental phases; heat treatment; microstructure; Metallurgy and Metallic Materials; Metallurgi och metalliska material; Corrosion Engineering; Korrosionsteknik
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-217355

In new low-lead and lead-free brass alloys, it is not understood how the corrosion properties,such as dezincification, are related to material composition as well as annealing temperatureand duration. This study aims to fill this knowledge gap by mapping sixteen annealingconditions and three different brass alloy compositions to their respective microstructure anddezincification performance. It was found that high dezincification depth was a result ofannealing temperatures at 300°C – 400°C, which promoted precipitation of intermetallicAlAs-particles along grain boundaries, twins and lead particles as well as precipitation of β-phase along grain boundaries. Their presence was correlated to high micro additions ofaluminium or iron in the material composition. An additional compositional factorcontributing to precipitation of high amount of β-phase was low copper/zinc-ratio.