Master thesis: Microstructure-corrosion interrelations in new lead-free brass alloys
Master thesis: Microstructure-corrosion interrelations in new lead-free brass alloys
Background
Brass is an alloy containing copper and zinc as main alloying elements. Other elements are added to improve specific properties, for example 2-3% lead for machinability or 0,1% arsenic for corrosion resistance. Brass is widely used in Sweden for drinking water distribution products, like faucets, couplings, valves etc. However, the brass industry is presently undergoing a major transition switching to low-lead and lead-free materials, due to new health and environmental regulations and pressure from the customers. This implies the use of new materials and need to address challenges related to these. Among others, there are corrosion concerns related to several of the new alloys used, which need to be addressed. The influence of the different alloying elements and processing parameters on the corrosion properties need to be understood in order to allow a safe production of brass components, which will be the aim of the proposed diploma work. This work is related to a larger industrial project involving the Swedish brass manufacturers.
The work will be performed at Swerea KIMAB AB, which is a Swedish research institute active within the fields of metallic materials and corrosion. We are located in Kista, Stockholm and employ around 150 persons.
Aim
The aim of this work is to determine the influence of chemical composition and heat treatments (at first hand stress relieving treatments) on the microstructure and corrosion properties of new and traditional brass alloys.
Description
This work will address these issues by combining alloy production, corrosion testing, microstructure study and analysis of the results.
The proposed diploma work will consist in following parts:
- Literature study – learning about the topic
- Production of samples for 4 different alloys through casting at laboratory scale and different heat treatments in order to obtain different microstructures
- Analysis of the microstructure of the samples (LOM and SEM)
- Corrosion testing of the samples obtained using at least two different methods (dezincification, grain boundary attack and possibly stress corrosion cracking)
- Analysis of the results through microscopy (LOM and SEM)
- Interpretation and reporting
The expected output is an understanding of the microstructures variables influencing corrosion properties and how they are determined by alloy composition and processing parameters.
Profile
Engineer studies within materials, chemistry or technical physics. Knowledge within metallic materials is expected. Knowledge related to corrosion is positive.
Application and time
Application to be done no later than February 22, by using the form below. The diploma work is to be started in March or April 2017 and has duration of 20 weeks.
Contact
David Lindell, +46 (0)8 440 48 52
david.lindell@swerea.se