The metal matrix composite is a hybrid material that exceeds the limitations of
two materials having different characteristics. Which is lightweight, has
excellent mechanical characteristics, thermal characteristics, and wear
resistance, and thus h...
The metal matrix composite is a hybrid material that exceeds the limitations of
two materials having different characteristics. Which is lightweight, has
excellent mechanical characteristics, thermal characteristics, and wear
resistance, and thus has been researched and applied in many fields. In this
study, FC250 cast iron with excellent abrasion resistance was used as a base
material and TiC ceramic particles were used as a reinforcing material to
manufacture a solid Fe-based metal composite material. To confirm its
applicability to areas requiring wear resistance, such as automobile brake discs
and bearing materials, various analyses were conducted through the following
experiments.
First, through a literature survey, what is the material of a commonly used
automobile disk, and the phenomenon that occurs in a harsh wear
environment, such as sudden braking and the principle of braking were
considered. When friction and wear occur in harsh environments such as the
braking of a car, a high temperature of 100 to 300°C is generated, and wear
phenomena progress faster. Cast iron, which is often used as a brake disc
material, is vulnerable to thermal deformation and wear due to thermal energy
accumulated when used for a long time in a wear environment and friction
between the brake disc and brake pad during braking. To compensate for this,
an FC250-based metal matrix composite with TiC reinforcement that is capable
of improving thermal resistance, wear resistance, and durability was
manufactured using the liquid pressing infiltration process.
Second, various heat treatments such as austempering and
quenching-tempering were applied to the FC250 cast iron and manufactured
TiC/FC250 materials to improve mechanical and wear properties, and
microstructure and characteristic changes due to heat treatment were
investigated. In addition, the wear behavior of the SUJ2 material, which is
well-known as the existing wear resistance material, was compared and
analyzed. The experimental method for observing wear behavior was
conducted using a ball-on-disk method using a ball-type counterpart. Because
it has high hardness and compressive strength due to the characteristics of a
composite, WC (tungsten carbide) was used as a counterpart for experiments.
The test was conducted by setting the load, speed, wear distance, and wear
test temperature applied to the wear test as variables.
Finally, phase change, microstructure change, wear width, and wear depth of
the metal matrix composite before and after the wear test was analyzed using
XRD and FE-SEM. As a result of the XRD analysis, it was confirmed that a
TiC particle-reinforced FC250 composite material without impurities was
prepared. It was observed that flake graphite was distributed in the matrix of
dendrite tissue in the case of FC250 materials, and TiC particles were
uniformly distributed in the case of TiC/FC250 composite materials. The metal
matrix composite that was subjected to quenching-tempering heat treatment
showed a hardness value that was about 5 times higher than that of the
existing base material and about 2 times higher than that of the existing metal
matrix. According to the test result, under all heat treatment conditions, the
friction coefficient of metal composite material decreased by 1/2 or more
compared to base material, the wear resistance was improved due to increased
hardness, and the friction coefficient of the metal matrix composite heat
treated with quenching-temping was the lowest. The quenching-tempering
treated metal matrix composite had the highest hardness value and excellent
abrasion resistance, so it seems that it can be applied to the heat treatment
of TiC/FC250 composite.