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An attempt has been made in this study to examine the dry sliding wear response of a leaded-tin
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bronze, an aluminum bronze, and a conventional zinc-based alloy under varying applied pressure
and speed conditions. Different characteristics of the microconstituents of the alloys have been cor-
related with that of their wear behavior. The study clearly indicates that the influence of the mi-
crostructural features greatly changes with the sliding conditions. It also has been observed that in
order to attain good wear characteristics, a material should comprise an optimum level of lubricating,
load bearing and ductile microconstituents, and, above all, thermal stability. Room temperature prop-
erties in fact play rather a secondary role in this context.5918
I. INTRODUCTION
THERE exist a number of alloys which can be used for
a variety of tribological and other engineering applica-
tions.
[1–7]
Sliding of one component over/against the other
occurs in many situations, bush bearings being one of the
important ones.
[1–7]
In general, leaded-tin bronzes are widely
used in bush-bearing applications[1,3,4–6]
while aluminum
bronzes are also used under specific service conditions.
[5]
Zinc-based alloys have been found to be cost- and energy-
effective substitutes to the bronzes in various sliding wear
applications.
[1–3,6,7]
From microstructural considerations, the
conventional bronze alloys are quite different from one an-
other. For example, the leaded-tin bronzes contain a con-
siderable quantity of the lubricating phase, lead; the
element increases the crack sensitivity of the alloy under
specific conditions of sliding.
[8,9]
The aluminum bronzes do
not contain any lubricating microconstituent but possess
very good thermal stability. Finally, in the case of zinc-
based alloys, the major microconstituent (i.e., zinc) is lu-
bricating in nature,
[10]
but the alloys suffer from poor
elevated-temperature properties.
[2]
It may be mentioned that the sliding wear response of
materials depends very much on their microstructural fea-
tures in terms of lubricating properties, crack sensitivity,
and thermal stability. In fact, the predominance of the fac-
tors under a specific sliding condition essentially controls
the wear behavior of the materials. Thus, sliding conditions
are the ones to govern the wear response of the materials.
Available information indicates that although the sliding
wear behavior of the leaded-tin and aluminum bronzes and
zinc-based alloys has been studied to some extent,
[8–22]
yet
the role of their microstructural characteristics on the slid-
ing wear response of the alloys has been investigated to a
limited extent
[8,9,11,12,15–20]
in spite of their great significance.
In view of this information, an attempt has been made
in this study to examine the influence of the role of various
microconstituents of a leaded-tin bronze, an aluminum
B.K. PRASAD, Scientist, is with the Regional Research Laboratory,
Habibganj Naka, Bhopal 462 026, India.
Manuscript submitted July 1, 1996.
bronze, and a zinc-based alloy on their sliding wear re-
sponse under varying conditions of applied pressure and
speed. Mechanical properties of the alloys have also been
correlated with their wear properties.
II. EXPERIMENTAL
A. Alloy Preparation
Alloys (Table I) were prepared by solidifying in the form
of 20-mm-diameter, 150-mm-long cylindrical castings us-
ing permanent molds. Elements used for preparing the al-
loys had purity levels above 99.95 pct.
B. Microstructural Characterization