Tensile Fracture Surface Morphology Research Articles

Effect of zirconium diboride addition in zirconium dioxide reinforced aluminum-based composite fabricated by microwave sintering technique

In the present investigation, zirconium dioxide (ZrO2) and zirconium diboride (ZrB2) have been used in the development of an aluminum-based composite. A microwave sintering technique was employed for the processing of the composite. The aluminum-based composite was developed with the constant 5 wt.% of ZrO2. The weight percent of ZrB2 increased from 2.5% to 7.5%. Uniform distribution of the reinforcement particles was observed for the composition Al–5 wt.% ZrO2–2.5 wt.% ZrB2 composite and Al–5 wt.% ZrO2–5 wt.% ZrB2 composite. The relative density of Al–5 wt.% ZrO2–5 wt.% ZrB2 composite was found to be 0.9874. The percent porosity of the Al–5 wt.% ZrO2–5 wt.% ZrB2 was 1.259%. Results showed that hardness, compressive strength, % tensile strength, and fatigue strength (at 1 × 107 cycles) were improved by about 74.28%, 18.18%, 58.77%, and 60.77%, respectively. XRD of the Al/ZrO2/ZrB2 composite showed the presence of Al, ZrO2, ZrB2, MgAl2O4, and Al2Cu phases. The number of grains per square inch for composition Al–5 wt.% ZrO2–5 wt.% ZrB2 composite was found to be 989.11. This result showed that a finer grain structure has been obtained after the solidification of Al–5 wt.% ZrO2–5 wt.% ZrB2 composite. The fracture surface of the Al–5 wt.% ZrO2–5 wt.% ZrB2 composite was composed of a dendrite structure with micro-porosities. Dimples were also not observed from the tensile fracture surface morphology of the composite.

Recovery of Al2O3/Al powder from aluminum dross to utilize as reinforcement along with graphene in the synthesis of aluminum-based composite

In the present study, waste aluminum dross was used as reinforcement in the development of an aluminum-based composite. Waste aluminum dross in the form of a mixture of Al and Al2O3 was collected from aluminum industries. Microwave sintering technique was employed for the processing of composite material. The composite was developed with the constant 5 wt. % of aluminum dross powder. Maximum hardness, compressive strength, and tensile strength were found for the composition Al-5 wt. % aluminum dross powder—5 wt. % graphene composite. However, minimum porosity was found for the composition Al-5 wt. % aluminum dross powder—5 wt. % graphene composite. Uniform distribution of the reinforcement particles was observed for the composition Al-5 wt. % aluminum dross powder—5 wt. % graphene composite. XRD of the Al/aluminum dross powder/graphene composite showed the presence of Al, Al2O3, and Al4C3 phases. The fracture surface of the Al-5 wt. % aluminum dross powder—5 wt. % graphene composite was composed of a dendrite structure with micro-porosities. Dimples were also not observed from the tensile fracture surface morphology of Al-5 wt. % aluminum dross powder—5 wt. % graphene composite.

Fabrication and properties of interweaved poly(ether ether ketone) composite scaffolds

This paper interweaved scaffolds with poly(ether ether ketone) (PEEK) and poly(lactic acid)/Walnut shell/hydroxypatite (PLA/WS/HA) composites by using fused filament fabrication technology, although there was a huge difference in thermal property term between PLA and PEEK. In order to keep mechanical properties of PEEK scaffold and remedy the stress loss produced by pores, PLA/WS/HA composites were used to fill the pores with gradient form outside-in (0.4-0.8 mm, 0.6-1.0 mm, 0.8-1.2 mm and 1.6-2.0 mm). The thermal stability, tensile and compression properties, tensile fracture surface morphology, cytotoxicity and in vivo experiment were investigated. The results showed: the scaffolds were intact without any flashes and surface destruction, and kept a well thermal stability. Compared with the PEEK porous scaffolds, the tensile fracture stress and strain, compression yield stress and strain of interweaved scaffolds were dramatically enhanced by 24.1%, 438%, 359.1% and 921.2%, respectively, and they climbed to the climax at 8 wt% of WS. In vivo experiment showed that the degradation of PLA/WS/HA composites synchronized with the adhesion, proliferation and ingrowth of bone cells, keeping the stable biomechanical properties of interweaved scaffolds. Those experiments showed that interweaved PEEK-PLA/WS/HA scaffolds had the potential to be used as bone implant in tissue engineering.

The Mechanical Properties of Aluminum Metal Matrix Composites Processed by High-Pressure Torsion and Powder Metallurgy.

Al-Al2O3 and SiC metal matrix composites (MMCs) samples with different volume fractions up to 20% were produced by high-pressure torsion (HPT) using 10 GPa for 30 revolutions of Al-Al2O3, and SiC and powder metallurgy (PM). The effect of the processing method of micro-size Al MMCs on the density, microstructure evolution, mechanical properties, and tensile fracture mode was thoroughly investigated. HPT processing produces fully dense samples relative to those produced using powder metallurgy (PM). The HPT of the Al MMCs reduces the Al matrix grain size and fragmentation of the reinforcement particles. The Al matrix average grain size decreased to 0.39, 0.23, and 0.2 µm after the HPT processing of Al, Al-20% Al2O3, and SiC samples. Moreover, Al2O3 and SiC particle sizes decreased from 31.7 and 25.5 µm to 0.15 and 0.13 µm with a 99.5% decrease. The production of ultrafine grain (UFG) composite samples effectively improves the microhardness and tensile strength of the Al and Al MMCs by 31-88% and 10-110% over those of the PM-processed samples. The good bonding between the Al matrix and reinforcement particles noted in the HPTed Al MMCs increases the strength relative to the PM samples. The tensile fracture surface morphology results confirm the tensile properties results.

Synthesis, Microstructural Characterization, Mechanical, Fractographic and Wear Behavior of Micro B4C Particles Reinforced Al2618 Alloy Aerospace Composites

In the current studies an investigations were made to know the effect of 63 micron sized B4C particles addition on the mechanical and wear behavior of aerospace alloy Al2618 metal composites. Al2618 alloy with different weight percentages (2, 4, 6 and 8 wt. %) of 63 micron sized B4C particles reinforced composites were produced by stir cast process. These synthesized composites were tested for various mechanical properties like hardness, compression strength and tensile behavior along with density measurements. Further, microstructural characterization was carried by SEM/EDS and XRD analysis to know the micron sized particles distribution and phases. Wear behavior of Al2618 alloy with 2 to 8 wt. % of B4C composites were studied as per ASTM G99 standards with varying loads and sliding speeds. By adding 63 micron sized B4C particles hardness, compression and tensile strength of Al2618 alloy was enriched with slight decrease in elongation. Further, wear resistance of Al2618 alloy was enriched with the accumulation of B4C particles. As load and speed on the specimen increased, there was increase in wear of Al2618 alloy and its composites. Various tensile fracture surface morphology and worn surface behavior was observed by SEM analysis.

Novel approach to recycled carbon fiber suitability assessment for additive technologies

This article presents a new approach to suitability assessment of short reclaimed carbon fiber (rCF) for additive technologies via commonly used analytical methods. Acrylonitrile butadiene styrene (ABS) based plastics reinforced with virgin or recycled CF samples were received, their mechanical properties and morphology of tensile fractured surface were determined by SEM (Scanning Electron Microscopy) and tensile strength test. As long as operating characteristics of CFRP are affected by single fiber strength as well as adhesion (interfacial interaction) between matrix and CF, this research also includes investigation of fiber surface with Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray diffraction (XRD). Correlation between suggested complex parameters of investigated CF and strength of plastics (CFRP) samples was shown. It was also established that contribution of each investigated parameter is additive.

Effect of microwave on mechanical properties of laser-sintered carbon nanotube polymer composites

ABSTRACT In this work, carbon nanotubes (CNT)/polyethersulfone (PES) polymer composites were prepared by selective laser sintering, and the effects of microwave treatment on mechanical properties and tensile fracture surfaces of the composites were investigated. The experimental results indicated that tensile strength and bending strength of the composites upon microwave treatment for 5–25 s were improved by 4–20.4% and by 4.5–47.7%, respectively. The tensile fracture surface morphology of the composites depended on the time length of microwave treatment. Upon microwave treatment, the fracture surface showed fewer pores and better interfacial bonding between adjacent polymer particles. The fracture mechanisms for the microwave-treated carbon nanotube/polymer composites prepared by selective laser sintering were discussed.

Effect of stacking sequence and fiber content on mechanical and morphological properties of woven kenaf/polyester fiber reinforced polylactic acid (PLA) hybrid laminated composites

Hybrid laminated composites were fabricated from woven kenaf, woven polyester and polylactic acid (PLA) using the hot compression method. The hybrid composites consist of woven material as reinforcement having the fiber weight-matrix ratio of 40:60. Six samples of hybrid laminated composites were prepared in different stacking sequences using the hand lay-up method. The laminates were prepared and tested based on ASTM International standard method for tensile, flexural and impact properties. S4 samples yield the highest tensile strength, elongation and impact strength among the hybrid composites that were recorded at 103 MPa, 17.88% and 84 kJ/m2, respectively. However, the composition of woven kenaf and woven polyester influenced the result obtained for flexural strength. Higher composition of woven kenaf in hybrid laminated composites exhibited better flexural properties. The tensile fracture surface morphology was evaluated using field emission scanning electron microscopy (FESEM). The data gathered could provide understandings of new hybrid laminated composites for industrial applications such as automotive, structural, and non-structural applications.

Multi-objective mathematical modeling and optimization of delta straight InterPulse-GTCAW parameters to predict and maximize performance of high temperature aerospace alloy sheets for structural applications

Superalloy 718 is a high temperature nickel (Ni) based alloy, widely used in aeroengines due to its superior mechanical performance at high temperature. It is vulnerable to alloying segregation and Laves phase precipitation in fusion zone (FZ) which deteriorates the tensile properties of Superalloy 718 joints. Hence a newly emerged InterPulse GTCAW process featured by high frequency arc constriction was attempted to fabricate the joints of Superalloy 718. The main objective of this research work is mathematical modeling, prediction and optimization of delta straight GTCAW (DS-GTCAW) parameters for joining Superalloy 718 using response surface methodology (RSM). The process parameters were optimized for maximizing the tensile properties of joints and attain desired FZ microstructure. The tensile properties of Superalloy 718 joints were predicted from the mathematical relationships of DS-GTCAW parameters. The optical and scanning electron microscopy was used to characterize the microstructural features and tensile fracture surface morphology of high strength and low strength joints of Superalloy 718. The energy dispersive spectroscopy was used to characterize the alloying segregation of FZ. The mathematical equations were also formulated to predict the tensile properties of Superalloy 718 joints from secondary dendritic arm spacing (SDAS) of FZ microstructure. The joint developed using optimized DS-GTCAW parameters disclosed 99.20% joint efficiency which is enhanced by 30% than GTAW and comparable to electron beam welded (EBW) and laser beam welded (LBW) joints of Superalloy 718. It refers to the refining of dendritic FZ microstructure and Laves phase precipitation in finer form.

Microstructure and Mechanical Properties of Tungsten Inert Gas Weld Joints of Sprayed and Cast Aluminium-Lithium Alloy.

The weld joints of sprayed 2195-T6 and cast 2195-T8 aluminium–lithium alloy were created using tungsten inert gas with filler wire. The microstructures and mechanical properties of the weld joints were examined. The results of the microstructure analysis showed that the width of the equiaxed grain zone (EQZ) and the amount of the second phase θ’(Al2Cu) was greater in the weld joint of the cast 2195-T8 Al–Li alloy than that of the sprayed 2195-T6 Al–Li alloy. Tensile testing indicated that failures occurred in the EQZ and partially melted zone (PMZ) for both weld joints. The tensile strength and elongation of the weld joints of the sprayed 2195-T6 and cast 2195-T8 Al–Li alloys were about 68.2%, 89.7%, and 50.7% and 28.3% those of the base metal in the joint, respectively. The cast 2195-T8 Al–Li alloy joint had more pores and cracks, resulting in lower tensile strength and elongation than those in the sprayed alloy. Further, the tensile fracture surface morphology indicated that the fracture mode of the sprayed 2195-T6 Al–Li alloy was a mixed fracture mode dominated by plastic fracture and that of the cast 2195-T8 Al–Li alloy joints was a mixed fracture mode dominated by brittle fracture.

Study the effect of fiber orientation on mechanical properties of bidirectional basalt fiber reinforced epoxy composites

The mechanical behaviors and tensile fracture surface morphology of basalt bidirectional mat fiber based epoxy composites were investigated in the present experimental work. Composites with varying fiber orientation angles such as 45°, 60° and 90° laminated using hand layup techniques. Mechanical behaviors like as tensile strength and tensile modulus, flexural strength and flexural modulus, impact strength (charpy & izod) as well as micro hardness behaviors investigated experimentally. The result showed that maximum mechanical properties obtained in 90° fiber orientation composite as compared to other developed composites.

Effect of heat input on microstructure and properties of dissimilar laser welded joints between TWIP and TRIP steels

In this present, the experimental steels were produced by different rolling and heat treatment processes. After that, dissimilar laser tailor welding was carried out with different heat inputs (40, 60 and 100 J/mm2) using IPG YLR 6000 fiber laser with Ar gas shielding. Hitachi SU5000 scanning electron microscope (SEM) and Zeiss Axio Vert.Al optical microscope were used to observe the microstructure of the welded joints after being polished and etched with 4% nital. HV-1000 microhardness tester was used to measure the microhardness of welded joints. Tensile test was carried out using DNS-100 universal material testing equipment, and Erichsen test was conducted using CTM604 Erichsen test machine. Five groups of repeated experiments were selected for the performance test. Tensile fracture surface morphology of welded joint was observed by SEM. The effect of heat input on microstructure and properties of dissimilar welded joints between high manganese TWIP steels and low manganese TRIP steels was studied. The results showed that weld width and penetration were increased and complete penetration was obtained when the heat input increased to 60 J/mm2. With heat input increased, the microstructure of welded seam was more inhomogeneous. The distribution of Mn content in welded seam was inhomogeneous such that columnar/equiaxed austenite was formed in rich Mn zone and lath martensite was formed in barren Mn zone. Heat input had no influence on the microstructure and hardness on the HAZ. The mechanical properties of welded joints of 60 J/mm2 were superior and its strength-ductility balance was greater than TRIP BM (23 GPa%) and was 82% of TWIP BM (36 GPa%). The formability of 60 and 100 J/mm2 was similar.

Mechanical, morphological, structural and dynamic mechanical properties of alkali treated Ensete stem fibers reinforced unsaturated polyester composites

Present study deals the surface morphology and structural composition analysis of alkali (NaOH) treated 2.5% 5.0% and 7.5 wt% Ensete stem fiber obtained from the Ethiopian Ensete ventricosum plant. Treated Ensete fibers reinforced unsaturated polyester (UP) composites were characterized in terms of tensile, flexural, surface morphology and dynamic mechanical properties. Mechanical test results revealed that 5.0 wt% alkali treated Ensete fibers/UP composites showed 14.5% and 43.5% increase in flexural strength and Young's modulus respectively, with relative to untreated Ensete fibers/UP composites. Storage and loss modulus value also highest for 5.0 wt% alkali treated Ensete fibers/UP composites. Moreover, a positive shift in glass transition temperature (Tg) of composites after alkali treatment and tensile fracture surface morphology indicates better interfacial interaction in treated Ensete fibers/UP composites. Overall we concluded that 5.0 wt% treated Ensete fibers satisfactorily and effectively improved mechanical, morphological and dynamic properties of UP for various engineered and hi-tech applications.

Tungsten carbide, boron carbide, and MWCNT reinforced poly(aryl ether ketone) nanocomposites: Morphology and thermomechanical behavior

ABSTRACTThis study involves the development and thermo‐mechanical characterization of the individual, binary, and ternary nanocomposites using radiation resistant fillers like boron carbide (B4C), tungsten carbide (WC), and functionalized multi‐walled carbon nanotubes (F‐MWCNT) in a high performance polymer, namely, poly aryl ether ketone (PAEK). Transmission electron microscopy studies revealed the distribution and dispersion of nanofillers in the matrix. It has been observed that the presence of WC and F‐MWCNT in PAEK matrix significantly enhanced the tensile strength of the composite whereas B4C made it stiff and brittle in nature. The tensile property improvement caused by WC and F‐MWCNT has been correlated with the tensile fracture surface morphology studies. Dynamic mechanical analysis provided insight into the positive effect of nanofillers in delaying the relaxation of polymer chains. The thermogravimetric analysis gave indications on the increase in the thermal stability of the nanocomposites with the increase of nanofillers content. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47032.

Microbial desulfurization for ground tire rubber by mixed consortium-Sphingomonas sp. and Gordonia sp.

Sphingomonas sp., Gordonia sp. and their mixed consortium were used to desulfurize ground tire rubber (GTR), respectively. The microorganisms' growth characteristic was studied and desulfurization effect on GTR was evaluated systematically by measuring the water contact angle, swelling values, crosslink density and element content of rubber samples. Besides, the mechanical properties of SBR (styrene butadiene rubber) composite filled with GTR and DGTR (desulfurized ground tire rubber) were studied and the morphology of tensile fracture surface was observed. The results showed that the biomass of the mixed bacteria was higher than any single bacteria during co-culture desulfurization process, which indicated that these two kinds of bacteria can promote each other and grow together. After desulfurized by the mixed bacteria, the crosslink density of DGTR decreased by 9.5% and sulfur content on surface decreased by 32.4%, which changed more obvious than DGTR treated by single strain. Besides, the mechanical properties of SBR/DGTR composites were higher than those of SBR/GTR composites, and among all these SBR composites, the one filled with DGTR treated by the mixed bacteria had best mechanical properties. The interface coherence between DGTR and SBR matrix was enhanced, too. It indicated that these two kinds of bacteria can promote each other to grow together and get better desulfurization effect.

Microstructural characteristics, mechanical and wear behaviour of aluminium matrix hybrid composites reinforced with alumina, rice husk ash and graphite

The microstructural characteristics, mechanical and wear behaviour of Aluminium matrix hybrid composites reinforced with alumina, rice husk ash (RHA) and graphite were investigated. Alumina, RHA and graphite mixed in varied weight ratios were utilized to prepare 10 wt% hybrid reinforced Al-Mg-Si alloy based composites using two-step stir casting. Hardness, tensile properties, scanning electron microscopy, and wear tests were used to characterize the composites produced. The results show that Hardness decreases with increase in the weight ratio of RHA and graphite in the composites; and with RHA content greater than 50%, the effect of graphite on the hardness becomes less significant. The tensile strength for the composites containing o.5wt% graphite and up to 50% RHA was observed to be higher than that of the composites without graphite. The toughness values for the composites containing 0.5wt% graphite were in all cases higher than that of the composites without graphite. The % Elongation for all composites produced was within the range of 10–13% and the values were invariant to the RHA and graphite content. The tensile fracture surface morphology in all the composites produced was identical characterized with the presence of reinforcing particles housed in ductile dimples. The composites without graphite exhibited greater wear susceptibility in comparison to the composite grades containing graphite. However the wear resistance decreased with increase in the graphite content from 0.5 to 1.5 wt%.

Improvement in the mechanical performance and interfacial behavior of kenaf fiber reinforced high density polyethylene composites by the addition of maleic anhydride grafted high density polyethylene

The effects of compatibilizer on the tensile, flexural and interfacial adhesion behavior of kenaf fiber reinforced high density polyethylene composites were investigated. The addition of maleic anhydride grafted high density polyethylene (MA-HDPE) as compatibilizer into the composites was found to improve the mechanical properties and the adhesion behavior of the composites. These improvements were due to the improved compatibility between matrix and fiber. 8 % MA-HDPE loading provided maximum enhancement in tensile and flexural properties when compared to the other compatibilizer contents. Meanwhile, uncompatibilized composites showed poorer mechanical properties and interfacial behavior relative to the compatibilized composites. Fourier transformed infrared spectroscopy analysis confirmed the changed chemical structures by the appearance of stretching vibration of the ester carbonyl groups (C = O) around 1725 cm−1 to 1742 cm−1 and the peak of hydroxyl group at 3327 cm−1 in the compatibilized composites. This indicates that the maleic anhydride has bonded to the kenaf fiber through esterification reaction, giving rise to strong interfacial bonding between the matrix and fiber. The improvement in the interfacial behavior was evident from the tensile fracture surface morphology using a field emission scanning electron microscopy.

Effect of coir fiber loading on mechanical and morphological properties of oil palm fibers reinforced polypropylene composites

Hybrid composites were fabricated by compounding process with varying the relative weight fraction of oil palm empty fruit bunch (EFB) and coir fibers to assess the effect of hybridization of oil palm EFB with coir fibers in polypropylene (PP) matrix. The mechanical and morphological properties of oil palm/coir hybrid composites were carried out. Tensile and flexural properties of oil EFB-PP composites enhanced with hybridization of coir fibers except coir/oil palm EFB (25:75) hybrid composite, whereas highest impact properties at oil palm:coir fibers with 50:50 ratios. Results shown that hybrid composites with oil palm:coir fibers with 50:50 ratios display optimum mechanical properties. In this study, scanning electron microscopy (SEM) had been used to study morphology of tensile fractured surface of hybrid composites. Its clear from SEM micrograph that coir/EFB (50:50) hybrid composites display better tensile properties due to strong fiber/matrix bonding as compared with other formulations which lead to even and effective distribution of stress among fibers. The combination of oil palm EFB/coir fibers with PP matrix produced hybrid biocomposites material can be used to produce components such as rear mirrors' holder and window levers, fan blades, mallet, or gavel. POLYM. COMPOS., 35:1418–1425, 2014. © 2013 Society of Plastics Engineers

Bentonite as a reinforcing and compatibilizing filler for natural rubber and polystyrene blends in latex stage

Bentonite clay was used as a reinforcing and compatibilizing filler for natural rubber/polystyrene (NR/PS) blend via latex blending process. The reinforcing and compatibilizing performance of bentonite clay in the NR/PS blends were evaluated. The improvement of the mechanical properties of NR/PS blends with the weight ratios of 90/10, 80/20, and 70/30 was found with the addition of 3 and 5 parts per hundred rubber (phr) clay. The characterization by using Fourier transform infrared spectroscopy and X-ray diffraction (XRD) gave the evidence that the silicate layer was intercalated by NR and PS molecular chains. The morphology of tensile fracture surface by scanning electron microscope showed the separated phase boundaries of PS and NR blend and gradual disappearance with the bentonite content. This could be implied that the bentonite contributes to the compatibilization between PS and NR. The compatibilization action of the bentonite clay was also reflected by the shift of glass transition temperature (Tg) of NR to higher temperatures than those of the blends. These results suggested that the tensile and tear properties of the blends were controlled by compatibility between NR and PS. The most enhanced properties of blends were found with the addition of 3 phr bentonite clay. POLYM. ENG. SCI., 54:1436–1443, 2014. © 2013 Society of Plastics Engineers

Influence of surface modification of carbon nanotube on microstructures and properties of polyamide 66/multiwalled carbon nanotube composites

AbstractThe melt‐mixing polyamide 66 (PA66) composite samples that incorporated pure, acid‐ and amine‐functionalized multiwalled carbon nanotubes (MWCNTs) were prepared in order to enhance mechanical and frictional properties of PA66 composites. The homogeneous dispersion of amine‐functionalized MWCNTs (D‐MWCNTs) in PA66 matrix was observed from the significantly uniform morphology of tensile fractured surface of the composites. Differential scanning calorimetry measurement indicates that D‐MWCNTs acted as effective nucleation agent for PA66 matrix and the crystallinity of PA66 was increased. The fracture stress and tensile modulus of the composites were significantly improved with the incorporation of D‐MWCNTs, owing to the good dispersion of D‐MWCNTs. Compared with PA66, the PA66 composites with 1.0 wt% D‐MWCNTs were improved considerably in both wear and friction properties owing to the change of the tribological mechanisms. The good dispersion of D‐MWCNTs in PA66 and good interface compatibility between D‐MWCNTs and PA66 favored the formation of a thin layer on the contact surfaces during wear and friction test, which played an important role in reducing wear and friction of the composite and in suppressing the transverse cracks. These results prove the importance of D‐MWCNTs in a positive change of the mechanical and frictional properties of PA66 composites and suggest the applicability prospect of PA66/D‐MWCNTs composites in engineering components.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers