Engineering and Technology Journal

This research investigated the impact of friction stir processing on grain
refinement in the surface layer of composite materials. The in-situ composite was
created by stir casting, incorporating 15% pure Ni into the Al matrix type A356.
Microstructural analysis performed with optical microscopy and X-ray diffraction
revealed the formation and dispersion of intermetallic phases such as AlNi, Al3Ni,
and Al3Ni2, contributing to significant grain refinement. FSP further enhanced the
micros structure by breaking and uniformly distributing small particles, including
the primary Si phase and Al₃Ni, while refining α-Al dendrites. These
microstructural changes resulted in improved mechanical properties, including a
13.81% increase in hardness for the A356/Al3Ni composite and a 14.47% increase
for the base A356 alloy. Wear rate tests were conducted using a ball-on-disc
apparatus under dry sliding conditions for both the base alloy A356 and the in-situ
composite A356/Al3Ni, before and after FSP. Compared to the base alloy A356
and in situ composites before and after friction stir processing, the in-situ
composite (A356/Al3Ni) after FSP exhibited a lower wear rate. However, during
the wear test, the coefficient of friction decreased as the applied load increased for
the base alloy A356 and the in-situ composite (A356/Al3Ni) following the friction
stir process.

The corrosion of implanted metals in the human body results in degradation and
the release of harmful ions. Titanium and its alloys are used in biomedical
applications due to their corrosion resistance and biocompatibility. This study
examines how the amount of time spent sintering affects the density and corrosion
resistance of Ti, Ti-6% Al, and Ti-6 % Al-2% HA (hydroxyapatite). Al was
incorporated into Ti to reduce its density and enhance corrosion resistance. In
contrast, HA was added at 2%, which aims to improve bioactivity and facilitate
better integration with bone tissue. The samples were fabricated through powder
metallurgy by mixing for 4 hours, and the compaction was 550 MPa. We sintered
all samples at 1,300 °C, with varying sintering times of 60, 90, and 120 minutes.
The results indicated that samples sintered for 120 minutes exhibited the highest
relative densities: 91.55% for Ti, 92.89% for Ti-6%Al, and 93.24% for Ti-6%Al2%HA. These samples demonstrated the lowest corrosion rates, with 0.2075 mpy
for Ti, 0.01199 mpy for Ti-6%Al, and 0.003129 mpy for Ti-6%Al-2%HA. X-ray
diffraction analysis of the Ti-6%Al-2%HA sample revealed patterns that
corresponded to the titanium alloy and its byproducts, which included Ti,
CaTi₄P₆O₂₄, TiP₂O₇, TiO₂, and CaTiO₃. Atomic absorption spectroscopy analysis
found that only a small amount of titanium ions (0.912 ppm) was released, and no
aluminum ions were detected over 14 days. Additionally, the MTT assay
demonstrated 85.3% cell viability. These findings suggest that Ti-6%Al-2%HA
alloys have potential applications in biomedical implants due to their improved
corrosion resistance and biocompatibility

Electro-Discharge Machining (EDM) is a unique manufacturing method. Recently
developed thermo-electric methods include Nano Powder-Mixed Electric
Discharge Machining (NPMEDM), which suspends metallic Nanopowder in a
dielectric. This study examines how Al2O3 -SiO2 Nanopowder concentration and
mixing ratio affect EDM dielectric fluid surface integrity (outputs) on stainless
steel 304L. Material Removal Rate (MRR), Electrode Wear Rate (EWR), and
surface roughness (Ra) are used to evaluate machining efficiency. Nanofluid has
much better heat conductivity than dielectrics, enhancing material removal.
Material Removal Rate rises with discharge current. At Run No. 26, increasing
Al2O3 particle proportion with 35 A discharge current, 2 g/l particle concentration,
200 µs pulse on time, and 50 µs pulse off time increases material removal rate by
13%. Increasing discharge currents lowers Ra. Lowering discharge current to 20
A, particle concentration to 3 g/l, pulse on time to 150 µs, and pulse off time to 75
µs lowered aluminium oxide particle composition to 50%, increasing Ra by 4.5%
at Run No. 37. Increased discharge currents lower EWR. By increasing discharge
current to 25 A, particle concentration to 4 g/l, pulse on time to 200 µs, and pulse
off time to 100 µs, aluminium oxide particle composition was reduced to 40%,
leading to a 33.3% rise in EWR at Run No. 50 using Design Expert 11 software.
Current 37.8%, pulse on 12.6%, nanopowder concentration 3%, and pulse off
25.85% are needed for MRR. The mixing ratio parameter does not affect MRR.
EWR needs 25.5% current and 25.6% nanopowder. Ra depends on nanopowder
concentration, peak current at 4.5%, pulse-off duration at 20.24%, current-pulse
duration at 7.6%, and current-pulse off duration at 37.9%.

Bone plates are necessary for bone fracture healing since they adapt the biomechanical micro-environment at the fracture location to provide the essential
mechanical fixation for the fracture fragments. This research concentrates on
decreasing the influence of stress shielding that takes place owing to an
incompatibility between the metallic plate and the cortical bone by using a
composite material based on biopolymer bio-epoxy thermosetting material
reinforced by natural pumpkin powder at a fixed weight fraction (2 wt.%) for all
lamination sample in addition to fiber reinforcement which involves different
layers of flax woven fabrics mainly in addition to woven Carbon fibers, woven
Glass fibers, as laminates which prepared by hand layup technique. Thus, the
prepared specimens were exposed to the flexural max shear stress, impact, and
surface roughness tests. The results manifested an improvement in composite
properties (the flexural strength, flexural modulus, impact strength, fracture
toughness, max: shear stress, and surface roughness) by the addition of flax fibers.
Also, hybrid laminate bio-composites with natural and synthetic reinforcement
recorded the best results among other composites. Also, the (2% pumpkin powder
+ 4-layer flax/2 layers Carbon fiber) biocomposites have the best result in terms
of flexural strength, flexural modulus, and maximum. Shear stress and impact
strength values rise from (62.5 MPa), (2.1 GPa), (4.37 MPa), and (5.6 KJ/m2
) to
reach (210 MPa), (5.27 GPa), (12.18 MPa), and (94.37 KJ/m2), respectively. The
SPSS program was also used to analyze the results of this study statistically.
According to the current study, Laminate fiber-reinforced composites are the
materials most recently probed as possible candidates for internal fracture fixation
implants by placing different woven fabric reinforcements.

This study investigates the influence of small liquid metal gallium additions (1,
1.5, 2, and 2.5 wt%) on the antibacterial performance of Ti, Ti-15Mo, and Ti-45Zr
alloys fabricated by the powder metallurgy method. The alloys were manufactured
by sintering at 1250 °C to improve the antibacterial activity of Titanium and its
alloys in biomaterial applications. X-ray diffraction (XRD) was used to identify
the dominant compounds and phases after adding liquid gallium metal, and the
antibacterial activity was also tested; the results indicate an increase in the Zone
of inhibition of Ti, Ti-15Mo, and Ti-45Zr with increasing gallium/Ga content,
where the Zone of inhibition increased by approximately 12, 12.5 and 18% for Ti,
Ti-15Mo, and Ti-45Zr, respectively. This is attributed to Ga³⁺, which disrupts irondependent enzymes and metabolic pathways (e.g., DNA synthesis, electron
transport), inhibiting bacterial growth. Adding Ga alters the alloy's surface
topography and chemistry, reducing bacterial adhesion. A smoother or more
hydrophobic surface prevents bacterial colonization and biofilm formation.
Titanium and its alloys with liquid gallium metal were also shown to be non-toxic
biomaterials with biocompatibility properties for MCF-10 cells. Ga additives for
Ti, Ti-15Mo, and Ti-45Zr improve antibacterial performance, making these alloys
promising for medical implants and reducing infection risks without relying on
antibiotics. Further optimization of Ga concentration and release kinetics is critical
to balance efficacy and biocompatibility.

The construction industry’s reliance on ordinary Portland cement (OPC) contributes
significantly to CO₂ emissions and resource depletion. Geopolymer concrete (GPC)
offers a sustainable alternative, but natural aggregates (NAs) still harm the
environment. This study investigates recycled coarse steel slag aggregate (RCSA), a
metallurgical byproduct, as a partial replacement (10, 20, 30, and 40% by volume) for
natural coarse aggregate (NCA) in metakaolin-based GPC. The geopolymer paste was
formulated with optimal molar ratios of 3.65 for SiO₂/Al₂O₃, 2.9 for sodium hydroxide/
sodium silicate, and 0.62 for water/metakaolin. Results showed that incorporating
RCSA enhances both mechanical and physical properties of GPC. Optimal
performance was achieved with a 30% RCSA substitution, showing remarkable
improvements over conventional GPC at 28 days of curing: a 29.56% increase in
compressive strength (95.1 MPa vs. 73.4 MPa), along with 26.12 and 41.07%
enhancements in splitting tensile and flexural strengths, respectively. Bulk density
increased by 8.15% (2371.96 kg/m³ vs. 2193.12 kg/m³). In comparison, physical
analysis revealed a 26.32% reduction in porosity and a 9.18% decrease in water
absorption, indicating improved interfacial transition zone (ITZ) between the RCSA
and geopolymer paste, facilitated by calcium leaching from the slag particles, which
promotes densification and reduced permeability. Microstructural analyses (XRD
and FTIR) confirmed successful geopolymerization and a robust amorphous
geopolymer network. Findings confirm RCSA mitigates environmental impacts
through waste valorization and significantly enhances GPC performance, offering a
viable pathway toward more sustainable construction materials.

This study investigates the effect of Ag–PTFE nanocomposite coatings, prepared
by radio frequency (RF) sputtering, on the surface and antimicrobial properties of
orthodontic stainless steel archwires (SSW). The novelty lies in combining silver
(Ag) and polytetrafluoroethylene (PTFE) nanoparticles into one coating, which
has not been widely applied to orthodontics. The motivation is the need to reduce
microbial adhesion and biofilm on archwires, which contribute to enamel
demineralization, gingival disease, and infections. The problem addressed is the
lack of coatings that can simultaneously provide enhanced surface properties,
facilitate controlled silver ion release, and deliver durable antibacterial
performance. Unlike literature that mainly studied Ag or polymer coatings
separately, this work fills the gap by varying Ag and PTFE weight percentages and
assessing their combined effects on wettability, roughness, ion release, and
antimicrobial activity. Austenitic 316L stainless steel archwires (0.4 mm in
diameter and 160 mm in length) were coated using Ag and PTFE nanopowders
(30 nm). The coated SSW was characterized using field emission scanning
electron microscopy (FESEM), X-ray diffraction (XRD), and contact angle
measurements, while silver ion release was analyzed by atomic absorption
spectroscopy. Antimicrobial efficacy was tested against Streptococcus mutans and
Staphylococcus aureus. The results showed uniform coatings with distinct
hydrophobic behavior and antibacterial activity. Increasing Ag content enhanced
silver ion release and inhibition zones, while higher PTFE content increased
hydrophobicity, reducing bacterial adhesion. These findings highlight Ag–PTFE
coatings as a synergistic strategy to improve surface properties and suppress
microbial colonization, suggesting potential benefits in preventing caries and
periodontal complications.

Dissimilar welding joints of different grades of stainless-steel pipes using various
welding processes and technologies have received special attention in the world of
manufacturing in the last few years, due to the wide application of different grades
of this material in different sectors, including refineries, chemical plants, heat
exchangers, and power generation plants. The utilization of rotary friction welding
has significantly increased, and more studies on it have been conducted to reduce
the difficulties of joining similar and dissimilar materials in general and steel in
specific, as it decreases the heat input and thermal cycle. This study investigated
the effect of continuous drive rotary friction welding and process parameters on
microstructure and mechanical properties of the dissimilar joint of austenitic and
super duplex stainless steel. The result of the study shows a significant relation
between the friction and forging parameters and the joint quality. The best result
achieved in this study was when the process parameters were selected as 30MPa
for friction pressure, 10 seconds for friction time, 20 MPa and 30 seconds for
forging pressure and time, respectively, and the rotational speed of 1030 rpm. The
result reveals that the effect of the process parameters that have the most effect on
heat input is more significant. And heat input in this process is a key point in
achieving a good or poor joint quality.

This study investigates the effect of chemical treatment on the mechanical
properties of bamboo particle-reinforced grafted binary rubber blend systems
(RTV-SIR/PUR), particularly for medical applications such as Solid Ankle
Cashion heel (SACH) prosthetic feet. The Grafted binary rubber blend composite
is consisting of Polyurethane (PUR) with (10, 20, and 30 wt.%) of Room
temperature vulcanized silicone rubber (RTV-SIR) with presence of 0.1% of
Tetraethoxysilane (TEOS) as coupling agent to more compatibility, and added
different percentage of treated bamboo particles (3, 6, and 9 wt.%) that treated by
5% of Sodium Hydroxide (NaOH). The effectiveness of the alkali treatment in
eliminating contaminants, enhancing the surface appearance of natural bamboo
particles, and improving the bonding between the particles and blend constituents
was verified using field emission scanning electron microscopy (FE-SEM). The
molecular composition of the samples was assessed using Fourier transform
infrared spectroscopy (FTIR). Samples were made utilizing vacuum desiccators.
The Mechanical properties, including tensile, tear, compression, and hardness,
were measured by a material testing system. The results show that a grafted binary
blend composite exhibits better mechanical properties when containing less than
30% RTV-SIR. In contrast, increasing the loading of treated bamboo particles to
9 wt.% results in the best properties of the samples. This grafted composite rubber
blend is supported by the results presented in this study, which demonstrate a new
composition for SACH feet that replaces traditional materials (polyurethane foam)
and is feasible due to the use of liquid materials.

This study evaluated the tribological properties of an eco-friendly brake pad.
Pentaclethra macrophylla pod was pulverized into powder form and sieved. Two
particle sizes of 150 μm and 210 μm were obtained after sieving, and the sieved
particles were divided into two portions, with one portion carbonized and the other
uncarbonized. The brake pad composite was produced by varying the composition
of powdered reinforcement in the order of 10, 20, 30, 40, and 50 wt.%. The
formulation was poured into a metal mould 50 × 50 × 8 mm3
, placed in a hot platen
press at a temperature of about 180 °C, a molding pressure of 15 MPa, and a curing
time of 5 minutes. Post-heat treatment of the composites was performed in a hot
air oven for a period of 4 hours at 180 °C. The produced brake pads were evaluated
for wear rate, coefficient of friction, and flame resistance. The results showed that
the coefficient of friction and flame resistance of the brake pads increased as the
weight percentage composition of the powdered reinforcement increased, while
the wear rate decreased. The 150 μm particle size of the powdered reinforcement
recorded higher coefficient of friction values and lower wear rate. The carbonized
powdered reinforcement had better resistance to the flame test. Wear rate value of
3.19 mg/m, coefficient of friction value of 0.3-0.4, and flame resistance of about
8.2% showed that powdered reinforcement is a promising reinforcement material
for the production of eco-friendly brake pads.

Magnetic Abrasive Finishing (MAF) is a highly effective technique for enhancing
the surface integrity of high-value components with complex geometries, owing
to its non-contact, flexible, and precisely controllable nature. This study
investigates the use of Al₂O₃ (alumina) powder as an abrasive medium in the MAF
process, selected for its high hardness, thermal stability, and chemical inertness.
Although Al₂O₃ is only weakly paramagnetic, it was successfully incorporated into
the magnetic abrasive brush through mechanical blending with ferromagnetic
particles that respond to the magnetic field. This hybrid abrasive system enables
effective control of finishing forces, leading to significant improvements in surface
quality and the elimination of surface defects. A series of controlled experiments
was conducted to evaluate the influence of key process parameters—rotational
speed, working gap, abrasive mixing ratio, and processing time—on surface
roughness and material removal. The results demonstrated that the inclusion of
Al₂O₃ in the MAF process significantly enhanced surface finish and micro-crack
removal without compromising dimensional accuracy. Optimal finishing
performance was achieved at a rotational speed of 630 rpm, a gap of 1.8 mm, and
a mixing ratio of 30%, resulting in a maximum surface roughness improvement of
33.7%. Furthermore, the elimination of micro-cracks contributed to a substantial
increase in fatigue resistance. While most trials yielded consistent results, one test
showed slightly lower performance due to an increased working gap, reduced
brush flexibility, and potential contamination from dense Al₂O₃ particles. The
study suggests that Al₂O₃-enhanced MAF is a promising method for extending the
service life of metal components.

This study evaluates the biomechanical performance of a novel curved
biodegradable ZK60 magnesium alloy locking plate for plate osteosynthesis in
midshaft femoral fractures classified as AO/ASIF 32-A3 (Arbeitsgemeinschaft für
Osteosynthesefragen/Association for the Study of Internal Fixation). Current
metallic implants are associated with complications such as stress shielding, the
need for secondary surgery, and limited support for biological healing.
Biodegradable options offer promising solutions but remain insufficiently studied,
especially regarding curved plate designs. This work addresses that gap by
systematically assessing how plate thickness and curvature influence fracture
stability. Finite element analysis (FEA) was performed under physiological
loading of 700 N simulating a single-leg stance. Ten configurations were modeled,
combining two thicknesses (4 and 6 mm) with five bending angles (0, 5, 10, 15,
and 20°). A 5 mm fracture gap was simulated, and all constructs were fixed with
bicortical locking screws. Axial stiffness and total deformation were calculated
and compared with those of an intact femur. Results indicated that both increased
plate thickness and curvature enhanced construct performance. The 6 mm plate
bent at 20° showed the highest stiffness (2328.9 N/mm) and lowest deformation
(0.3007 mm), representing a 6.6% increase in stiffness and 5.8% reduction in
deformation compared with the flat counterpart. Similar trends were observed for
the 4 mm plate. The evaluated designs achieved 23.8–25.4% of intact femur
stiffness, aligning with the biomechanical window that promotes callus formation
through controlled micromotion. Curved configurations also improved load
transfer and screw alignment. Among the tested designs, the 6 mm plate bent at
15°–20° demonstrates the most favorable biomechanical characteristics for
potential clinical translation.

This study presents an integrated work that combines unconventional machining
and finishing techniques for complex geometric models. A Taguchi design
investigated three electrical-discharge parameters—electric current, pulse
duration, and gap—each at three levels; a multi-objective optimization matrix was
then used to select the optimal conditions. The geometric models were designed
using SolidWorks software and machined on a CNC machine to ensure maximum
accuracy in the resulting samples. The samples were finished using the magnetic
abrasive finishing technique, where the particle mixture was developed as a hybrid
blend of two types of abrasive particles, tungsten carbide (WC) and silicon carbide
(SiC). Among the electrical discharge machining factors, electric current showed
the highest influence, yielding a maximum metal removal rate of 25.1024
mm³/min at Ip = 42 A, Tn = 300 µs, gap = 8 mm, and the minimum roughness of
11.6674 µm at Ip = 24 A, Tn = 150 µs, gap = 5 mm. The magnetic abrasive
finishing stage substantially improved the surface quality of the complex models,
reducing roughness from 11.9169 µm to about 4.29 µm, equivalent to a 64.02%
reduction. Within finishing, feed rate was the most influential variable, followed
by spindle speed, while particle size had the least effect. Overall, the combined
methodology improves process performance and post-process surface quality for
complex geometries while identifying the dominant parameters that govern
material removal and roughness outcomes.

This study investigates the mechanical performance of 3D-printed polylactic acid
and polyethylene terephthalate glycol materials by examining the effects of three
crucial printing parameters (layer thickness, infill density, and infill pattern). Each
material was tested mechanically for impact toughness, flexural strength, ductility,
and ultimate tensile strength (UTS) using a Box-Behnken Design (BBD) to create
15 samples. The statistical significance of each parameter's impact was evaluated
using ANOVA. The findings showed that, for PLA, layer thickness had no
discernible impact on impact toughness (p = 0.726), while infill density (p = 0.031)
and infill pattern (p = 0.049) had the most significant effects. In PETG, layer
thickness (p = 0.038) and infill pattern (p = 0.021) significantly impacted impact
toughness. None of the parameters had a statistically significant impact on the
flexural strength of either material.PETG was highly responsive to the same factor
(p = 0.022), and PLA was highly sensitive to the infill pattern (p = 0.003) regarding
ductility. Both materials' UTS were significantly impacted by infill density, and
PETG showed a high sensitivity to the infill pattern (p = 0.004). The ideal
parameters for polyethylene terephthalate glycol (PETG) were a tri-hexagonal
pattern, a 0.3 mm layer thickness, and an 80% infill density; for polylactic acid
(PLA), they were a 0.15 mm layer thickness, an 80% infill density, and a grid infill
pattern. These optimized settings were successfully used to create a PETG-based
skull implant and functional test prints, demonstrating the applicability of the
optimization strategy in practical situations.