scholarly journals Microstructure and mechanical properties of MWCNT/Ti6Al4V composites consolidated by vacuum sintering

2020 ◽  
Vol 52 (2) ◽  
pp. 187-194 ◽  
Author(s):  
Doan Phuong ◽  
Duong Van ◽  
Nguyen Ngoc ◽  
Pham Van
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Load Transfer ◽  
Ti6al4v Alloy ◽  
Matrix Composites ◽  
Vacuum Sintering ◽  
Alloy Matrix ◽  
Multi Walled Carbon Nanotubes ◽  
Load Transfer Effect ◽  
Walled Carbon Nanotubes

Ti6Al4V alloys with low weight, high corrosion resistance, high melting point, high biocompatibility and unique mechanical properties have been receiving great attention for wide applicability in many industry fields such as automobiles, aerospace and biomedical. However, Ti6Al4V tends to be easily oxidized at high temperature, exhibit low thermal conductivity, low hardness and low yield strength and thus have led to the limitation of applicability in many industries. In this study, we have fabricated Ti6Al4V matrix composites reinforced with multi-walled carbon nanotubes (MWCNT) to enhance the hardness and yield strength. Vacuum sintering technique has been used to prepare MWCNT/Ti6Al4V composites. Microstructural and phase studies indicated that the composite structure consists of two main phases including ?-Ti and ?-Ti and MWCNTs were uniformly dispersed in Ti6Al4V matrix. The relative density of composite decreases as the CNT content increases as resulted from the porous structure of the CNT, which limits the aggregation process of the composite. When the CNT content increased, the hardness and yield strength of the composite increased, reaching maximum values of 378 HV and 356 MPa with 2 vol.% MWCNTs, which are nearly 16 and 38% higher than those of Ti6Al4V alloy. The enhancement in hardness and compressive strength is attributed to the good mechanical properties of MWCNTs and load transfer effect from Ti6Al4V alloy matrix to reinforcement material.

Dynamic Thermo-Mechanical Properties of Chemically Surface Modified MWCNTs Reinforced Polymeric Composites

2007 ◽  
Vol 26-28 ◽  
pp. 285-288 ◽  
Author(s):  
Abu Bakar Sulong ◽  
Joo Hyuk Park
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Polymeric Composites ◽  
Matrix Composites ◽  
Chemical Surface ◽  
Dynamic Mechanical Thermal Analyzer ◽  
Thermal Analyzer ◽  
Multi Walled Carbon Nanotubes ◽  
Surface Modified ◽  
Walled Carbon Nanotubes

The dynamic thermo-mechanical properties of two types of chemically surface modified (Carboxylated and Octadecylated) multi-walled carbon nanotubes (MWCNTs) and As produced MWCNTs reinforced epoxy matrix composites are investigated by Dynamic Mechanical Thermal Analyzer at 1.0 wt% concentration. Moreover, influence of MWCNTs concentration variations to the dynamic thermo-mechanical properties are evaluated at Carboxylated MWCNT reinforced polymeric composites (from 0.1 to 5.0 wt %). Higher interfacial bonding strength is achieved by introducing the chemical surface modification. Also MWCNTs reinforced polymer shows higher storage modulus (from 30°C to 70°C) than pure polymer. Moreover, the storage modulus of composites increases linearly by increasing MWCNTs concentration. However, glass transition temperature (Tg) of composites decreases linearly by increasing MWCNTs concentration.

scholarly journals Synergistic Effect of Multi-Walled Carbon Nanotubes and Graphene Nanoplatelets on the Monotonic and Fatigue Properties of Uncracked and Cracked Epoxy Composites

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1895 ◽  
Author(s):  
Yi-Ming Jen ◽  
Jui-Cheng Huang ◽  
Kun-Yang Zheng
Keyword(s):  
Mechanical Properties ◽  
Synergistic Effect ◽  
Load Transfer ◽  
Fatigue Properties ◽  
Integrated Analysis ◽  
Multi Walled Carbon Nanotube ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Cracked Specimens ◽  
Path Bifurcation

The fatigue properties of the polymer nanocomposites reinforced with a hybrid nano-filler system have seldom studied before. Accordingly, epoxy nanocomposites with various multi-walled carbon nanotube (MWCNT)/graphene nanoplatelet (GNP) filler ratios were prepared to study comprehensively the synergistic effect of the hybrid nano-fillers on the monotonic and cyclic mechanical properties of the nanocomposites. The quasi-statically tensile properties and fatigue-life curves were experimentally determined using uncracked bulk specimens. Additionally, pre-cracked specimens were utilized to study the fracture toughness and fatigue crack growth rate of the nanocomposites. A synergistic index based on the properties of the nanocomposites with individual types of filler was proposed to evaluate the synergistic effect of two employed nano-fillers on the studied properties. The index was verified to be a highly discriminatory tool to evaluate the synergistic effect of hybrid nano-fillers on the studied mechanical properties. The experimental results show that the composites with a MWCNT:GNP ratio of 1:9 have the higher monotonic and fatigue properties than those with other filler ratios. Adding appropriate amount of CNTs can prevent the agglomeration of GNPs. The flexible CNTs bridge adjacent GNPs to constitute a favorable network for load transfer. Moreover, there is a linear relationship between the static and fatigue strengths of the studied nanocomposites. Integrated analysis of experimental data and a fracture surface study reveals that the dispersion of nano-fillers influences the mechanical properties significantly. The crack deflection effect due to the path bifurcation caused by encountering the filler cluster and the filler bridging effect are the main reinforcement mechanism of the studied properties.

scholarly journals Microstructure and Mechanical Properties of Ti6Al4V Alloy Consolidated by Different Sintering Techniques

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1033
Author(s):  
Dinh Phuong ◽  
Van Duong ◽  
Van Luan ◽  
Ngoc Anh ◽  
Van Trinh
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Relative Density ◽  
Hot Isostatic Pressing ◽  
Lamellar Microstructure ◽  
Ti6al4v Alloy ◽  
Full Density ◽  
Compressive Yield Strength ◽  
Vacuum Sintering ◽  
Microstructure And Mechanical Properties

In this paper, we investigated the effect of the different sintering techniques including vacuum sintering, capsule-free hot isostatic pressing (HIP), and capsule HIP on the microstructure and mechanical properties of Ti6Al4V alloy. The obtained results indicated that full density Ti6Al4V alloy could be obtained by using capsule HIP technique. The alloy sintered by capsule HIP had the highest hardness (~405 HV) and compressive yield strength (~1056 MPa). It is interesting that the geometry has a significant influence on the relative density and mechanical properties of the alloy sintered by the capsule-free HIP. The relative density, hardness, and compressive yield strength rise from center to periphery of the specimen. This is attributed to the heating and pressing in the capsule-free, which are external, leading to the densification processes starting from the outside to the inner parts of the pressed specimen. Using theoretical prediction with Gibson and Ashby power law found that the yield strength of the alloy sintered by capsule-HIP technique is much lower than that of the calculated value due to the formation of the coarse lamellar microstructure of -Ti grains.

Microstructure and mechanical properties of novel CrCoNi–Al2O3P medium entropy alloy-matrix composites

2021 ◽  
Vol 130 ◽  
pp. 107057
Author(s):  
A.W. Zhao ◽  
X. Luo ◽  
Z.L. Ye ◽  
X. Guo ◽  
B. Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Matrix Composites ◽  
Alloy Matrix ◽  
Microstructure And Mechanical Properties

scholarly journals Understanding Covalent Grafting of Nanotubes onto Polymer Nanocomposites: Molecular Dynamics Simulation Study

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2621
Author(s):  
Seunghwa Yang
Keyword(s):  
Molecular Dynamics ◽  
Load Transfer ◽  
Cell Model ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Covalent Grafting ◽  
Modelling Strategies ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
External Loads

Here, we systematically interrogate the effects of grafting single-walled (SWNT) and multi-walled carbon nanotubes (MWNT) to polymer matrices by using molecular dynamics (MD) simulations. We specifically investigate key material properties that include interfacial load transfer, alteration of nanotube properties, and dispersion of nanotubes in the polymer matrix. Simulations are conducted on a periodic unit cell model of the nanocomposite with a straight carbon nanotube and an amorphous polyethylene terephthalate (PET) matrix. For each type of nanotube, either 0%, 1.55%, or 3.1% of the carbon atoms in the outermost nanotubes are covalently grafted onto the carbon atoms of the PET matrix. Stress-strain curves and the elastic moduli of nanotubes and nanocomposites are determined based on the density of covalent grafting. Covalent grafting promotes two rivalling effects with respect to altering nanotube properties, and improvements in interfacial load transfer in the nanocomposites are clearly observed. The enhanced interface enables external loads applied to the nanocomposites to be efficiently transferred to the grafted nanotubes. Covalent functionalization of the nanotube surface with PET molecules can alter the solubility of nanotubes and improve dispersibility. Finally, we discuss the current limitations and challenges in using molecular modelling strategies to accurately predict properties on the nanotube and polymers systems studied here.

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