Impact Toughness Of Composites Research Articles

Analysis and optimization of machining parameters of AZ91 alloy nanocomposite with the Influences of nano ZrO2 through vacuum diecast process

The magnesium alloy composite is a vital material for automotive applications due to its features like high stiffness, superior damping resistance, high strength, and lightweight. Here, the motto of research is to establish the AZ91 alloy nanocomposite with the exposures of 0, 1, 3, and 5 volume percentages (vol%) of nano zirconium dioxide (ZrO2) particles (50nm) through fluid stir metallurgy route associated with 1x105 Pa vacuum die cast process. Exposures on structural morphology, hardness, and impact toughness of composite are analyzed and identified as the nano AZ91 alloy composite enclosed with 5vol% is homogenous particle dispersion, enhanced hardness (97.6HV), and optimum toughness of 21.2J/mm2. However, composite faces machining difficulties due to the hard abrasive particles with higher hardness, resulting in tool wear. This experiment predicts the optimum mill parameters during the end mill operation of magnesium alloy nanocomposite (AZ91/5vol%) by using a tungsten carbide coated end mill cutter to attain the maximum metal removal rate with low surface roughness and tool wear analyzed via the general linear model (GLM) ANOVA approach. The input conditions for end milling operation vary, like feed rate (0.1 -0.4mm/rev), depth of cut (0.05 -0.2mm), and spindle speed (250-1000rpm). During the ANOVA GLM approach, the L16 design experiment is fixed for further interaction analysis. The results predicted by the depth to cut and feed rate were dominant and played a major role in deciding the tool wear, surface roughness, and MRR.

Nature‐Mimic Tough Helicoidal Composites with Aligned Short Carbon Fibers by 3D Printing

AbstractThis work develops nature‐inspired tough helicoidal composites with aligned short carbon fibers by 3D printing. The alignment of short carbon fibers (SCF) in the composite is achieved by shear flow during 3D printing process. First, unidirectional composites with aligned SCFs are prepared with various fiber contents ranging from 2 wt% to 10 wt%. It is found that the shear strength of the unidirectional composites with the SCFs perpendicular to the shear loading is the highest at a fiber content of 10 wt%, 46% higher than that of the pristine nylon. Then, helicoidal composites with four helical angles (i.e., 0°, 30°, 45° and 90°) are prepared using 3D printing. The impact testing results show that the impact toughness highly depends on the build orientation. The impact toughness of the composites with on‐edge build orientation is significantly greater than those with flat build orientation. The greatest impact toughness of the helicoidal composites is achieved at a helical angle of 45° with a value of 31.9±4.4 kJ m−2, which is mainly attributed to misaligned fiber plane‐induced crack deflection, forcing cracks to advance in multiple planes under impact.

Bioinspired 3D helical fibers toughened thermosetting composites

Thanks to the special helical structure, natural composites such as shell, wood, and bone have remarkable toughness, strength and damage tolerance. Herein, a bioinspired spiral nylon monofilament/epoxy composite is developed, which is a representative example of helical fiber/thermosetting composites. The relationship between toughness and strength of composites was studied by controlling parameters of the helical fibers. As a result, the impact resistance is regularly increased by the increase of pitch and the decrease of helix fiber angle. With a single-layer addition, the impact toughness of composites is increased by 150% without decreasing the mechanical strength and that is increased by 450% in the case of three-layer addition. The proposed toughening mechanism was verified by finite element analysis and dynamic mechanical analysis, which including 3D stress dispersion, the interlocking fibrous building interface, and energy absorption capacity of viscoelastic spring polymer. Furthermore, the toughness and strength of the composites is improved by 310% in single layer via surface modification of spiral fibers. The introduction of the three-dimensional spiral structure into the composite is demonstrated to be a unique strategy to overcome the trade-off between toughness and strength of high-performance composite materials.

Impact property of TiAl3–Ti laminated composite fabricated from metallic sandwich

TiAl3–Ti Laminated composite has been fabricated by hot pressing of titanium–aluminium sandwich in order to improve impact toughness of TiAl3. Fabrication process has been reported and structure evolution, phase portion, hardness, impact toughness, and fractography of the composite are investigated using XRD, XPS, SEM, EDS, hardness test, and impact test. The results show formation of TiAl3 and production of TiAl3–Ti laminated composite after the sandwiches have been hot pressed at 600 and 650 °C for 24 h in low vacuum system. TiAl3–Ti thickness ratio attributed to phase portion and hardness of TiAl3–Ti interface region are shown to be promoted by fabrication temperature. Fractography and EDS results can allow the impact–fracture mechanism of composite to be proposed. The impact toughness of composite can be improved by using low fabrication temperature in order to reduce TiAl3–Ti thickness ratio.

ENHANCING PERFORMANCE CHARACTERISTICS OF EQUIPMENT OF SEA AND RIVER TRANSPORT BY USING EPOXY COMPOSITES

Coatings based on epoxy diane oligomer ED-20 are being developed as environmentally benign, foulingresistant marine coatings. Silver oxide and carbonate (mixture) was used as filler, the dispersion of which is 0.5 µm. It is proved that for the formation of composites with the improved physical and mechanical properties it is necessary to add Mechanical Mixture of Silver Carbonate and Oxide (MMSCO) in the amount of q = 0.050…0.250 pts. wt. into the epoxy diane oligomer ED-20 (100 pts. wt.). The obtained values of impact toughness of composites during the introduction of MMSCO into the binder increased by 2.5 times compared to the epoxy matrix. Moreover, the maximum capacity to resist impact loads, including fracture toughness, was demonstrated by the Composite Material (CM) with the filler content q = 0.050 pts. wt. Impact toughness of this CM is а = 18.53 kJ/m2. The developed materials and protective coatings based on them were used on the dry cargo ship Oles Honchar.

A liquid‐like multiwalled carbon nanotube derivative and its epoxy nanocomposites

ABSTRACTMultiwall carbon nanotubes (MWCNTs) with liquid‐like behavior at room temperature were prepared with sulfonic acid terminated organosilanes as corona and tertiary amine as canopy. The liquid‐like MWCNT derivative had low viscosity at room temperature (3.89 Pa s at 20°C) and exhibited non‐Newtonian shear‐thinning behavior. The weight fraction of MWCNT in the derivative was 16.72%. The MWCNT derivative showed very good dispersion in organic solvents, such as ethanol and acetone. The liquid‐like MWCNT derivative was incorporated into epoxy matrix to investigate the mechanical performance of the nanocomposites and the distribution of MWCNTs in the matrix. When the liquid‐like MWCNT derivative content was up to 1 wt %, the flexural strength and impact toughness of composites were 12.1 and 124% higher than the pure epoxy matrix, respectively. Transmission electron microscope (TEM) confirmed the very good dispersion of the liquid‐like MWCNT derivative in epoxy matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2217–2224, 2013

Mechanical Performance of a New Coir Fiber Laminated Composites

In order to overcome the uneven distribution of coir fiber density in the materials and the poor forming of the outer surface, a new type of coir fiber hybrid laminated composites has been developed. The non-woven needle felts of coir fiber are added as the core material, wood veneers are as the surface material, and E-type glass fiber felts are as the reinforcement material, the preparation of hybrid laminated composites has been carried out. Through the performance testing and scanning electron microscopy (SEM) analysis, a new type of biomass composite with excellent performance has been successfully developed. The application of coir fiber to obtain good impact toughness of composites has been effectively verified.

Grafting of Poly(n-butylacrylate)-b-poly(2-hydroxyethyl methacrylate) on Carbon Fiber and its Effect on Composite Properties

A treatment method based on the grafting of block copolymer on carbon fiber (CF) surface was proposed for obtaining a controlled interface between carbon fibers and epoxy resin. The block copolymer poly(n-butylacrylate)-b-poly(2-hydroxyethyl methacrylate) (PnBA-b-PHEMA) was grafted on the CF by controlled polymerization. Research shows that the grafting block copolymer can improve interfacial adhesion, and the chain structure, lengths and grafting density of block copolymer can affect the fiber/matrix interfacial adhesion. The study of mechanical properties indicated the introduction of PnBA-b-PHEMA in the interface could both improve the flexural strength, modulus and impact toughness of composites.

Properties of Weft Knitted Composites Affected by Preform Stretching

The influence of preform stretching on mechanical properties of weft knitted PP/glass fibre composites was estimated. Stretching of Rib 1:1 weft knitted fabric was performed prior to consolidation in a wale or course direction and biaxially. Preform stretching increased tensile and bending strength of composite as a result of additional orientation of the reinforcing fibres in the stretching direction. Stretching in a wale direction was shown to be most effective due to the specific inherent structure of Rib 1:1 fabric. The impact toughness of composites was not significantly changed as a result of decreased preform elasticity in the direction of stretching.