Journal of University of Science and Technology Beijing
Volume 13, Number 6, December 2006, Page 1
Corresponding author: Akhtar Farid, E-mail: faridmet22@hotmail.com
Stainless steel binder for the development of novel TiC reinforced steel cermets
Akhtar Farid, Shiju Guo, Xia Yang, and Yudong Lian
Materials Science and Engineering School, University of Science and Technology Beijing, Beijing 100083, China
(Received 2006-02-12)
Abstract: Steel reinforced TiC composites are attractive choice for wear resistance and corrosion resistance applications. TiC rein-
forced 17-4PH maraging stainless matrix composites were processed by conventional powder metallurgy (P/M). TiC-maraging
stainless steel composites with a density of >97% of theoretical density were produced. The microstructure, mechanical and wear
properties of developed composites were evaluated. The microstructure of these composites consisted of (core-rim structure) round
and semi round TiC particles. A few microcracks appeared in the composite showing the presence of tensile stresses in the composite
produced during sintering. Typical properties, hardness and bend strength were reported for the sintered composites. After heat
treatment and aging, the increase of hardness was observed. The increase of hardness was attributed to the aging reaction in 17-4PH
stainless steel. The precipitates appeared in the microstructure, which were responsible for the increase in hardness. The specific
wear behavior of the composites was strongly dependent on the content of TiC particles, the interparticle spacing and the presence of
hard precipitates in the binder phase.
Key words: TiC-based cermets; binder phase; maraging stainless steel; aging; microcracks
1. Introduction
The incorporation of ceramics reinforcements into
metal matrices to produce composite materials with
improved properties has been a subject of intensive
investigations during the past three decades. Ceramics
metal composites are widely used for the manufacture
of high performance wear parts and cutting tools.
Ideally cermets display physical properties that com-
bine the hardness of a ceramic phase with the tough-
ness of a metal matrix. Most of the work on metal ma-
trix composites is centered on the lighter structural
metals Ti, Al and Mg primarily to attain improved
strength and stiffness [1-3]. There is also a significant
interest in developing TiC reinforced Fe and steel
based metal matrix composites mainly to produce a
combination of excellent wear resistance with im-
proved toughness and to achieve significant cost re-
ductions over existing competitive materials e.g.
WC-Co cemented carbides [4-7]. Titanium carbide is
considered as a promising reinforcing material for the
development of metal matrix composites due to its
hardness, high melting point, high chemical and ther-
mal stability, high wear resistance, high solvency of
other carbides, good wetability and their relative
thermal stability with many binder materials [1, 8-9].
However, despite the progress in material processing
and incorporation of new binder materials, the actual
quality of titanium carbide metal matrix composites
still restricts possible wear applications of this materi-
al. Even today best TiC-reinforced cermets still pos-
sess lower mechanical properties than other competi-
tive materials (WC-Co hardmetals) [8]. The availabil-
ity of titanium carbide reinforced cermets, when
compared with WC-Co hardmetals in market, only
underlies the fact that full potential of this material has
yet to be realized.
Binder phase is an important constituent of cermets
and strongly influences the final properties of the
composite. In cermets, wear resistance, hardness, bend
strength are the major properties of concern and these
properties are not only a function of TiC particles vo-
lume fraction and TiC particle size, but also strongly
depend on the binder phase distribution, microstruc-
ture and mechanical properties. Various binders have
been used to produce TiC based cermets to refine and
enhance their properties (mechanical, corrosion and
high temperature properties) and applications. Al, Ni,
Ni
3
Al, FeAl, NiCr, NiMo and various types of steels
have been used as the matrices in TiC-base cermets [8,
9-17]. Various steel binders used are listed in Table 1.
Improvements in materials processing, introduction of
new materials as binder phase has enhanced the prop-
erties and broaden the applications of TiC-base cer-
mets. Many studies have focused on the reinforcing
materials like TiC, WC, TiC and WC, TiC and VC,
TiC and TiB
2
etc. [2, 5, 8, 13], but this study will give