Investigation of Mechanical and Tribological Properties of Mg-alloy based Hybrid Reinforced Composite Fabricated through Powder Metallurgy
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Date
2025-11
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Department of Mechanical Engineering, NITS
Abstract
Advancements in material science have driven the rapid development of magnesium-based
metal matrix composites (Mg-MMCs) to meet the growing demands of modern engineering
applications. These composites offer an excellent strength-to-weight ratio, improved
corrosion and wear resistance, and the ability to withstand elevated temperatures, making
them ideal for high-performance applications. While pure magnesium has poor mechanical
and physical properties, its limitations can be mitigated by incorporating reinforcements,
such as ceramic particles in the form of fibers, whiskers, or particulates. These
reinforcements greatly improve the strength, ductility, toughness, and abrasion resistance of
the composites. The synergistic interaction between the magnesium matrix and reinforcing
particles results in microstructural refinement and optimization of the composite’s
mechanical behaviour.
However, challenges such as inhomogeneous distribution, poor wettability, and weak
interfacial bonding between the matrix and reinforcements often arise during liquid
metallurgy-based fabrication techniques. Researchers have increasingly adopted the powder
metallurgy technique to address these limitations. Overall, magnesium metal matrix
composites are recognized as promising candidates for advanced structural and functional
applications, providing a well-balanced combination of lightweight characteristics and high
mechanical integrity.
In this research, hybrid composites of magnesium alloy (AZ91) reinforced with titanium
carbide (TiC) and reduced graphene oxide (rGO) were studied. The powder metallurgy
method was used to synthesize magnesium alloy-based hybrid composites. The tribological
behaviour of fabricated composite samples were examined using a pin-on-disc tribotester
per the ASTM G99 standard. Using the Taguchi method, the design of the experiment (DOE)
was constructed. And, the L9 orthogonal array opted for tribo-performance evaluation. Also,
an ANOVA and regression analysis were carried out to ascertain the relative impact of the
tribological factors on the responses. In the present investigation, three variable factors were
considered, i.e., reinforcement percentage of TiC (0-10%) keeping constant 0.5 wt.% rGO,
disc sliding velocity (0.5 to 1.5 m/s), and applied load varies between 10 to 30 N. It was
found that the load parameter had a considerable impact on both the wear rate (WR) and the
coefficient of friction (COF). Sliding velocity, on the other hand, had a minimal effect on
WR. The concentration of reinforcement exhibits a moderate impact. Taguchi’s predictive
results were also compared with experimental results. The optical microscope (OM)
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examination of the microstructure of the fabricated hybrid Mg-MMC revealed significant
grain refinement and a uniform distribution of reinforcement, thereby enhancing the
microstructure. The worn surfaces were analyzed using scanning electron microscopy
(SEM), and surface characterizations were used for wear mechanics analysis.
In further research, the tribological and mechanical behavior of Mg-hybrid nanocomposites
has been studied. Magnesium alloy (AZ91) based composite were fabricated by reinforcing
nano-sized titanium carbide (nano-TiC), with weight percentages (wt.%) varying from 0.5%
to 2% while maintaining a constant 0.5 wt.% of nano-reduced graphene oxide (rGO)
throughout the experiments. Hybrid magnesium metal matrix nanocomposites
(HMMMNCs) were prepared using a powder metallurgy procedure. The microhardness and
compressive strength of the composite samples showed a significant improvement, with
increases of approximately 45.9% and 44.3%, respectively, compared to the matrix material.
This improvement in strength is attributed to the synergistic reinforcement effect of both
nano-TiC and rGO. Additionally, at the optimal nano-TiC concentration of 1.5 wt.%, the
wear rate and coefficient of friction (COF) of the HMMMNCs were decreased by ~40.7%
and ~49.33%, respectively. This reduction is primarily due to the formation of a hardened
ceramic phase in the contact region, which mitigates heat-induced softening. Additionally,
various analytical tools, including XRD, SEM, and a surface roughness profilometer, were
utilized to characterize the developed composite materials and analyze the worn surfaces.
The analysis of the worn surfaces revealed that abrasive wear was the dominant wear
mechanism at lower loads, whereas higher loads and sliding speeds led to adhesive wear,
plastic deformation, and transfer film formation.
Mg-MMCs have garnered significant interest across various industries, including
automotive, aerospace, electronics, sports, marine, and equipment manufacturing. Further
research is recommended to explore alternative processing methods as well as to examine
the wear behaviour of HMMMCs under diverse environmental conditions. Additionally, the
scope of analytical modeling and simulation may be considered in future work to predict and
validate the tribological and mechanical performance of HMMMCs under different loading
and environmental conditions.