A systematic study has been performed on the effect of alloying elements arsenic (As), antimony (Sb) and phosphorus (P) on the dezincification resistance of α-phase in brass. The result showed that P formed particles with Al and Fe already at relatively high temperatures, leaving no P in solid solution and thus no protection against dezincification. Arsenic only formed particles at lower temperatures and offers a satisfactory protecting. However, with increasing As levels grain boundary attack was observed. Samples alloyed with Sb show a satisfactory resistance to dezincification and no grain boundary attack. Finally, a combination of As and Sb at low alloying levels provided an excellent dezincification resistance for brass containing typical impurity levels. This paper is part of a Themed Issue on Brass Alloys.

Stress relieving heat treatment has been reported to deplete the corrosion resistance of new low-lead and lead-free brass alloys. How the heat treatment, processing and material composition relates to the microstructure and corrosion performance is not well understood. The present study aims to fill this knowledge gap by mapping stress relieving annealing conditions and different standardized compositions to their respective microstructures and dezincification performance.It was found that loss of corrosion resistance was only the most severe for alloys with higher aluminium and iron content. These alloys displayed significant precipitation of intermetallic AlAs-particles on grain boundaries, twins and lead particles, as well as the formation of β-phase along grain boundaries.

The thematic issue of Materials Science and Technology contains a selection of papers hand-picked from the 2016 Brass Alloys conference held in Stockholm 25-27 May 2016.Brass is one of the oldest alloys in widespread use today and for this reason it is often considered that there is little new to say about it. Conferences on copper alloys are few and far between; the last was in France in 2006 and we are not able to recall any previous meeting that was specifically devoted to brasses. This situation is seriously neglectful of an industry that turns over some $18 billion per annum and which is currently transforming itself in the face of various challenges.Brass has several attributes that make it almost indispensable in industrial production. It is relatively inexpensive and can be readily formed by casting, forging and machining processes. Correctly alloyed, it presents excellent resistance to corrosion, finding innumerable uses in hydraulics of most kinds. It also possesses good mechanical properties, in particular remarkable ductility in sheet forming. This latter feature is a result of very fine scale mechanical twinning whereby brass preceded the now so fashionable TWIP steels by many centuries.What, then, are the questions which are so pressing that they attracted more than seventy international attendees for three days of discussions in Stockholm? The most evident and urgent is the concern regarding lead as an alloying element in brass. Lead, in additions up to about 3%, remarkably improves the hot-workability and, in particular, the machinability of brass, with significant benefit to its economic competitiveness. However, environmental concerns are raising a large question mark over the use of lead in any circumstances so alternative solutions are very actively being sought with many different approaches. Authorities in the EU and elsewhere have not yet banned lead in these applications but they award approvals over limited periods of time with no guarantee of their renewal. Lead in brass is, accordingly, living on borrowed time.