Comparative Considerations on the Microstructures of Cast and Spray
Formed Complex Aluminium Bronzes
Gunter Benkißer ( Sp ), Universität Rostock, Institut für Werkstoffkunde,
J.Eberlein, R.Kaps, Mecklenburger Metallguss Waren,
K.Ohla, Wieland — Werke Ulm
1.Introduction
Complex aluminium bronzes with high aluminium contents ( more than about 10 mass - % )
posses low friction coefficients and low wear losses in contact with other metallic alloys,
especially in contact with ferritic and austenitic stainless steels / 1, 2 /. Therefore these alloys
are suitable for the production of some wear loaded engineering parts and tools. In Table 1 a
collection is presented of such applications.
Wrought alloys ' applications a nn
Cu Al10 Fe3 Mn2 slide bearings, gear wheels, worm wheels
Cu All1 Nib Fe5 ' drawing and deep drawing tools, high loaded
slide bearings LL
CuAOMn2 sparkless tools, slide bearings
Cu Al14 Fe Mn Co* drawing and deep drawing tools ]
Cast alloys }
G -Cu Alll Ni gear wheels, worm wheels, slide bearings
G ~ Cu All5 Fe5 Co** drawing and deep drawing tools I
G — Cu All4 Fe5** drawing and deep drawing tools
G —- Cu All5 Fe7 Mn** drawing and deep drawing tools
* not standardized, spray formed + hot pressed + heat treated,
** not standardized, cast and partly heat treated
Table 1: Examples of the applications of complex aluminium bronzes with a high wear resistance
In the present time spray formed bronzes are applied additionally to the conventional cast and
hot worked alloys / 3, 4 /. The spray forming produces a grain refinement of the
microstructure and a more homogeneous distribution of the alloying elements in the
microstructure in comparison to the cast bronzes. The details of the spray forming are
presented in the poster / 5 /. Additional it is remarked , that spray formed alloys are frequently
hot worked and heat treated.
The purpose of the lecture is a presentation of the microstrutures of cast and spray formed
complex aluminium bronzes in dependence of the chemical composition and the processing,
especially of the heat treatment.
2. Materials and experimental procedures
The chemical composition of the investigated alloys is shown in Table 1. The aluminium is
the most important alloying element, because it determines essentially the transformation
behaviour of the alloy ( Fig. 1 ). The aluminium content of the cast alloy is a little higher
compared to the spray formed alloy. The other elements ( iron, nickel, manganese and cobalt )
also influence the transformation behaviour and the formation of the microstructure. Firstly
these elements shift the phase boundaries in the phase diagrams ( Fig. 1). Secondly they
retard or suppress the diffusion processes and in connection with it the kinetics of the
diffusion controlled solid state transformations, especially of the eutectoid reaction at 565°C.
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