Microstructure and castability of lead‐free silicon brass alloys

Development of lead free brass alloys is an important subject due to the environmental demands and new regulations and standards that restrict lead contamination to decrease the toxicity. Pb‐free Si brasses are interesting alloys for this application, due to economical aspects and promising properties. In this work four Pb‐free brasses prepared with 1, 2, 3 and 4 wt% Si, based on Cu60/Zn40 alloy, are characterized. Their microstructure is examined and phases formed are identified. Castabilty indicated by fluidity and porosity is studied and correlated with the phases formed and their volume fraction.     

Zur Produktgestaltung kohäsiver Pulver – Mechanische Eigenschaften,Kompressions‐ und Fließverhalten

Product Design of Cohesive Powders – Mechanical Properties, Compression and Flow Behavior The three yield conditions of a powder continuum (incipient yield, stationary flow, consolidation) are formulated on basis of particle mechanics by the model ?stiff particles with soft contacts“. So that the direct influence of contact behaviour on flow behaviour is analytically shown. The powder compression behaviour is characterised by a compressibility index. Additionally the compression rate and the specific compression work are explained. So that the correlation between contact compliance, adhesion force intensification and powder flowability can be physically consistent evaluated. The response functions of extreme stressing and flow conditions at material conversion processes, storage and transport can be sufficiently described by these models. Obviously, suitable conclusions may be also drawn to design marketable products of processing industries.