Different fatigue behavior between tension-tension and tension-compression of carbon nanotubes reinforced 7055 Al composite with bimodal structure

The potential applications of carbon nanotubes (CNT) in many engineered bionanomaterials and electromechanical devices have imposed an urgent need on the understanding of the fatigue behavior and mechanism of CNT under cyclic loading conditions. To date, however, very little work has been done in this field. This paper presents the results of a theoretical study on the behavior of CNT subject to cyclic tensile and compressive loads using quasi-static molecular simulations. The Atomistic Finite Element Method (AFEM) has been applied in the study. It is shown that CNT exhibited extreme cyclic loading resistance with yielding strain and strength becoming constant within limited number of loading cycles. Viscoelastic behavior including nonlinear elasticity, hysteresis, preconditioning (stress softening), and large strain have been observed. Chiral symmetry was found to have appreciable effects on the cyclic loading behavior of CNT. Mechanisms of the observed behavior have been revealed by close examination of the intrinsic geometric and mechanical features of tube structure. It was shown that the accumulated residual defect-free morphological deformation was the primary mechanism responsible for the cyclic failure of CNT, while the bond rotating and stretching experienced during loading/unloading played a dominant role on the strength, strain and modulus behavior of CNT.

Download Full-text

Preparation and Mechanical Property of MWNTs/Al Composite Wires by Rotational Friction Extrusion Processing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.833.261 ◽

2013 ◽

Vol 833 ◽

pp. 261-265 ◽

Cited By ~ 1

Author(s):

Qi Ping Xiong ◽

Li Ming Ke ◽

Fen Cheng Liu ◽

Qiang Liu ◽

Xi Liang Chen

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Aluminum Matrix ◽

Aluminum Composite ◽

Extrusion Processing ◽

Al Composite ◽

Multi Walled Carbon Nanotubes ◽

Friction Extrusion ◽

Walled Carbon Nanotubes ◽

Composite Wires

The multi-walled carbon nanotubes (MWNTs) reinforced aluminum composite wires were fabricated by Rotational Friction Extrusion Processing (RFEP). The microstructure and mechanical properties of MWNTs/Al composite wires with different content of MWNTs were investigated. The results show that carbon nanotubes were well dispersed into the aluminum matrix, and the mechanical properties of MWNTs/Al composit wires were improved by FSP and RFEP. The tensile strength reached up to 186.3MPa when 4.5vol% MWNTs was added, which was 1.13 times that of MWNTs/Al composite blocks prepared by FSP only.

Download Full-text

Effect of multiwalled carbon nanotube alignment on the tensile fatigue behavior of nanocomposites

Journal of Composite Materials ◽

10.1177/0021998317745585 ◽

2017 ◽

Vol 52 (17) ◽

pp. 2365-2374 ◽

Cited By ~ 4

Author(s):

Sasidhar Jangam ◽

S Raja ◽

K Hemachandra Reddy

Keyword(s):

Carbon Nanotubes ◽

Fatigue Life ◽

Carbon Nanotube ◽

Composite Structures ◽

Fatigue Behavior ◽

Crack Propagation Rate ◽

Dimensional Structure ◽

Multiwalled Carbon ◽

Weight Percentage ◽

Tensile Fatigue

The one-dimensional structure of carbon nanotubes makes them highly anisotropic, making them to possess unusual mechanical properties, and hence employed as promising nanofiller for the composite structures. However, various carbon nanotube properties are not completely utilized when they are used as reinforcement in composites due to inadequate and immature processing techniques. In the present work, an attempt has been made to utilize the strong anisotropic nature of multi-walled carbon nanotubes (MWCNTs) for improving the fatigue life of nanocomposites only by considering a very low weight percentage (<0.5 wt%). The anisotropy of MWCNTs was imparted into the nanocomposites by aligning them in the epoxy matrix with DC electric field during composite curing. Nanocomposites were made for three MWCNT loadings (0.1, 0.2, and 0.3 wt%). The tensile fatigue behavior was investigated under stress control by applying cyclic sinusoidal load with the frequency range of 1–3 Hz and stress ratio, R = 0.1. The specimens were tested for the fatigue load until the failure or 1E+05 cycles. The fractured surfaces were examined through scanning electron microscope to analyze the fatigue fracture behavior. A small weight percentage of MWCNT loading (0.2 wt%) into the polymer composite has enhanced on an average 13% to 15% fatigue life, which is encouraging to develop the low cost, improved fatigue life composite structures. Also, the energy dissipation mechanism in MWCNT dispersed nanocomposites has shown a reduced crack propagation rate.

Download Full-text

FATIGUE BEHAVIOR OF SiC/Al COMPOSITE MATERIALS

Mechanical Behaviour of Materials VI ◽

10.1016/b978-0-08-037890-9.50185-x ◽

1992 ◽

pp. 421-426

Author(s):

H. ISHII ◽

K. TOHGO ◽

H. ARAKI ◽

K. OHSIMA

Keyword(s):

Composite Materials ◽

Fatigue Behavior ◽

Al Composite

Download Full-text

Fatigue Crack Behavior of Stainless Steel 304 by the Addition of Carbon Nanotubes

Journal of Nanomaterials ◽

10.1155/2014/863767 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6

Author(s):

Rizwanulhaque Syed ◽

Wei Jiang

Keyword(s):

Carbon Nanotubes ◽

Stainless Steel ◽

Fatigue Life ◽

Fatigue Behavior ◽

Crack Tip ◽

Cyclic Fatigue ◽

Compact Tension ◽

Fatigue Tests ◽

Stainless Steel 304 ◽

Number Of Cycles

Fatigue is the main source of almost half of whole mechanical failures. This research investigated the effect on cyclic fatigue behavior of stainless steel 304 (SS304) when including carbon nanotubes (CNTs) at the crack tip. The cyclic fatigue tests were conducted on compact tension (CT) specimens to establish the relationship between crack growth and the number of cycles (a-N). It is found that the incorporation of a small amount of CNTs increased the fatigue life of the SS304/metal. Micrographs showed that the enhancement in fatigue life is caused by CNTs dense arrangement around the crack tip, entangled with each other, and finer grain size. Smooth bonding at the interface of the CNTs and SS304 grains is also observed.

Download Full-text

Progress of the Current Interface Research on Carbon Nanotubes Reinforced Aluminum-Matrix Composites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.842.196 ◽

2013 ◽

Vol 842 ◽

pp. 196-200

Author(s):

Chun Wu ◽

Wen Xin Ma ◽

Ya Ping Chen ◽

Ying Li ◽

Yan Chen ◽

...

Keyword(s):

Carbon Nanotubes ◽

Composite Materials ◽

Aluminum Matrix ◽

Aluminum Matrix Composites ◽

Enhancement Effect ◽

Matrix Composites ◽

Key Factors ◽

Material Interface ◽

Preparation Methods ◽

Al Composite

The carbon nanotubes with its stable structure, excellent mechanical properties, become the ideal enhancement phase of composite materials. The enhancement effect is affected by various factors, interface is one of the key factors determine its enhancement effect, also is the research focus of metal matrix composites. Briefly introduced carbon nanotubes reinforced aluminum matrix (CNTs/Al) composite material interface bonding mechanism and interface effect on the properties of composite materials, thermal expansion coefficient and preparation methods were reviewed, purity of carbon nanotubes and other factors impact on CNTs/Alcomposites interface, and puts forward the way to improve interface.

Download Full-text

Fatigue behavior of Al2024 alloy-matrix nanocomposites reinforced with multi-walled carbon nanotubes

Composites Part B Engineering ◽

10.1016/j.compositesb.2017.09.034 ◽

2018 ◽

Vol 134 ◽

pp. 61-68 ◽

Cited By ~ 13

Author(s):

S.E. Shin ◽

D.H. Bae

Keyword(s):

Carbon Nanotubes ◽

Fatigue Behavior ◽

Alloy Matrix ◽

Multi Walled Carbon Nanotubes ◽

Al2024 Alloy ◽

Walled Carbon Nanotubes ◽

Matrix Nanocomposites

Download Full-text

Super-durable ultralong carbon nanotubes

Science ◽

10.1126/science.aay5220 ◽

2020 ◽

Vol 369 (6507) ◽

pp. 1104-1106 ◽

Cited By ~ 4

Author(s):

Yunxiang Bai ◽

Hongjie Yue ◽

Jin Wang ◽

Boyuan Shen ◽

Silei Sun ◽

...

Keyword(s):

Carbon Nanotubes ◽

Fatigue Resistance ◽

Fatigue Behavior ◽

Acoustic Resonance ◽

Test System ◽

Measurement Methods ◽

Small Samples ◽

Service Lifetime ◽

Resonance Test ◽

Individual Cnts

Fatigue resistance is a key property of the service lifetime of structural materials. Carbon nanotubes (CNTs) are one of the strongest materials ever discovered, but measuring their fatigue resistance is a challenge because of their size and the lack of effective measurement methods for such small samples. We developed a noncontact acoustic resonance test system for investigating the fatigue behavior of centimeter-long individual CNTs. We found that CNTs have excellent fatigue resistance, which is dependent on temperature, and that the time to fatigue fracture of CNTs is dominated by the time to creation of the first defect.

Download Full-text

Effect of Partially Recrystallized Structure Produced by Intense Plastic Deformation on Fatigue Behavior of an Al6%Mg0.3%Sc Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.715-716.831 ◽

2012 ◽

Vol 715-716 ◽

pp. 831-836 ◽

Cited By ~ 1

Author(s):

Elena Avtokratova ◽

Oleg Sitdikov ◽

Rustam Kaibyshev

Keyword(s):

Mechanical Properties ◽

Room Temperature ◽

Endurance Limit ◽

Volume Fraction ◽

Fatigue Behavior ◽

High Plasticity ◽

Ecap Processing ◽

Bimodal Structure ◽

Ultrafine Grains ◽

Average Size

t was shown that ECAP of an Al6%Mg0.3%Sc through route C at a temperature of 325°C (0.6Tm) to a total strain of 8 leads to the formation of partially recrystallized structure; the average size and the volume fraction of new ultrafine grains (UFG) were 1.2μm and 0.7, respectively. Areas of UFG structure alternate with coarse remnant parts of deformed original grains. Effect of this bimodal structure on room-temperature mechanical properties including fatigue behavior is examined. The ECAP processing led to increase in the yield strength and endurance limit accompanied with an insignificant loss of plasticity. Analysis of the surface features indicated that the fracture upon cyclic loading occurred by the transgranular mode in the regions of the unrecrystallized grains; this followed from the presence of striations in the large flat regions of the samples. In contrast, the fracture within regions of UFG grains occurred by the intergranular mode; distinct boundaries were clearly observed between the adjacent facets. It is concluded that the ultrafine grains presenting in the bimodal structure increase the strength characteristics of the alloy whereas the large remnant grains provide its relatively high plasticity. Therefore, the bimodal structure produced by the ECAP may ensure a certain balance between the rate of nucleation and propagation of a fatigue crack. The influence of this microstructure on the fatigue behavior of the material is discussed in detail.

Download Full-text