Structure, property and knittability of polyimide filaments with various strength and modulus

2018 ◽  
Vol 89 (5) ◽  
pp. 771-781 ◽  
Author(s):  
Fangbing Lin ◽  
Wei Li ◽  
Xiaodong Du ◽  
Jinhua Jiang ◽  
Nanliang Chen
Keyword(s):  
Experimental Investigation ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
High Strength ◽  
Chemical Compositions ◽  
Structure Property ◽  
Mechanical Behaviors ◽  
Performance Differences ◽  
Low Strength

This paper presents an experimental investigation on the knittability of various polyimide (PI) filaments, namely PI-H (high strength and modulus), PI-M (moderate strength and modulus) and PI-L (low strength and modulus) filaments. The tensile strength of the PI-H, PI-M and PI-L filaments is 3.41, 1.65 and 0.88 GPa, and the Young’s modulus is 92.94, 40.71 and 9.43 GPa, respectively. The chemical compositions and structures of various PI filaments were characterized to explain the mechanical performance differences. The results show that the imidization degree, structural crystallinity and orientation have significant effects on the mechanical behaviors of PI monofilaments. The filament forces during the knitting process are simplified into straight tensile, loop tensile and abrasion actions, which have been tested and analyzed on PI monofilaments. A home-made simulative knittability analyzer was designed to test the knittability of the PI filaments. A hand flat knitting machine was used to verify the validity of the simulating methods and the constructed knittability analyzer. The PI-H, PI-M and PI-L filaments have poor, moderate and excellent knittability, respectively. The results also demonstrate that the simulating methods and the constructed simulative knittability analyzer are reasonable and efficient to evaluate the knittability of PI filaments.

scholarly journals Kinetics of Capability Aging in Ti-13Nb-13Zr Alloy

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 693 ◽  
Author(s):  
Myoungjae Lee ◽  
In-Su Kim ◽  
Young Hoon Moon ◽  
Hyun Sik Yoon ◽  
Chan Hee Park ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
Young's Modulus ◽  
Solution Treatment ◽  
High Strength ◽  
Biomedical Implant ◽  
13Zr Alloy ◽  
American Society ◽  
Kinetics Of

Metals for biomedical implant applications require a simultaneous achievement of high strength and low Young’s modulus from the viewpoints of mechanical properties. The American Society for Testing and Materials (ASTM) standards suggest two types of processing methods to confer such a mechanical performance to Ti-13Nb-13Zr alloy: solution treatment (ST) and capability aging (CA). This study elucidated the kinetics of CA process in Ti-13Nb-13Zr alloy. Microstructural evolution and mechanical change were investigated depending on the CA duration from 10 min to 6 h. The initial ST alloy possessed the full α′-martensitic structure, leading to a low strength, low Young’s modulus, and high ductility. Increasing CA duration increased mechanical strength and Young’s modulus in exchange for the reduction of ductility. Such a tendency is attributed to the decomposition of α′ martensite into (α+β) structure, particularly hard α precipitates. Mechanical compatibility (i.e., Young’s modulus compensated with a mechanical strength) of Ti-13Nb-13Zr alloy rarely increased by changing CA duration, suggestive of the intrinsic limit of static heat treatment.

Graphene oxide and zinc oxide decorated chitosan nanocomposite biofilms for packaging applications

2020 ◽  
Vol 40 (2) ◽  
pp. 152-157 ◽  
Author(s):  
Pınar Terzioglu ◽  
Yasin Altin ◽  
Ayse Kalemtas ◽  
Ayse Celik Bedeloglu
Keyword(s):  
Tensile Strength ◽  
Zinc Oxide ◽  
Graphene Oxide ◽  
Composite Film ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
Young's Modulus ◽  
Chitosan Film ◽  
Oxide Composite ◽  
Wide Range

AbstractRecently, due to sustainable development and environmental protection policies, there is increasing interest in the development of new biodegradable polymer-based multifunctional composites. Chitosan is one of the most remarkable and preferred biopolymers, which is environmentally friendly as well as renewable, biocompatible, and inexpensive. Though it has a wide range of potential applications, the major limitation of chitosan – the problem of poor mechanical performance – needs to be solved. In this work, graphene oxide was first produced and then used to manufacture a chitosan/graphene oxide/zinc oxide composite film through a casting method. The properties of the chitosan film and the chitosan/graphene oxide/zinc oxide composite film were investigated using Fourier transform infrared spectroscopy, mechanical, thermal gravimetric, and ultraviolet (UV)-visible spectroscopy analyses. The results showed that the incorporation of graphene oxide and zinc oxide into the chitosan matrix resulted in enhanced mechanical properties and thermal stability of chitosan biocomposite films. The graphene oxide- and zinc oxide-reinforced chitosan film showed 2527 MPa and 55.72 MPa of Young’s modulus and tensile strength, respectively, while neat chitosan showed only 1549 MPa and 37.91 MPa of Young’s modulus and tensile strength, respectively. Conversely, the addition of graphene oxide decreased the transmittance, notably in the UV region.

Mechanical Properties of Hydrogen Functionalized Graphyne - A Molecular Dynamics Investigation

2012 ◽  
Vol 472-475 ◽  
pp. 1813-1817 ◽  
Author(s):  
Yu Lin Yang ◽  
Zhe Yong Fan ◽  
Ning Wei ◽  
Yong Ping Zheng
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
Young's Modulus ◽  
High Strength ◽  
Strength And Stiffness ◽  
Dynamics Simulations ◽  
Structure Engineering

In this paper the mechanical properties of a series of hydrogen functionalized graphyne are investigated through acting tensile loads on the monolayer networks. Molecular dynamics simulations are performed to calculate the fracture strains and corresponding maximum forces for pristine graphyne along both armchair and zigzag directions. Furthermore, hydrogen functionalized graphynes with different functionalization sites are analyzed to investigate the effect of functionlization on the mechanical performance. Finally, Young's modulus of all the investigated architectures are computed. The obtained results show that monolayer graphyne is mechanically stable with high strength and stiffness, and the mechanical performance can be tuned through structure engineering and functionalization.

scholarly journals Modulation of Multiple Precipitates for High Strength and Ductility in Al-Cu-Mn Alloy

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7383
Author(s):  
Linxiang Liu ◽  
Zhijun Wang ◽  
Qingfeng Wu ◽  
Zhongsheng Yang ◽  
Kexuan Zhou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Tensile Strength ◽  
High Strength ◽  
Mechanical Behaviors ◽  
High Tensile Strength ◽  
Transmission Electron ◽  
Evolution Pattern ◽  
Elongation To Failure ◽  
High Elongation ◽  
Strength And Ductility

The category and morphology of precipitates are essential factors in determining the mechanical behaviors of aluminum alloys. It is a great challenge to synthetically modulate multiple precipitates to simultaneously improve strength and ductility. In the present work, by optimizing the precipitations of the GP zone, θ’-approximant and θ’ phase for an Al-Cu-Mn alloy, a high tensile strength of 585 MPa with large elongation of 12.35% was achieved through pre-deformation and aging. The microstructure evolution pattern was revealed by detailed characterizations of scanning electron microscopy and transmission electron microscopy. It was found that such high tensile strength of the samples was due to a combination of strengthening by the high density of dispersive fine precipitates and dislocations, and the high elongation to failure was primarily attributed to the multimodal precipitates and elimination of precipitation-free zones along the grain boundaries. The strategy proposed here is a promising way of preparing ultra-strong Al-Cu-Mn alloys.

scholarly journals Performance of sustainable self-compacting fiber reinforced concrete with substitution of marble waste (MW) and coconut fibers (CFs)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jawad Ahmad ◽  
Fahid Aslam ◽  
Rebeca Martinez-Garcia ◽  
Mohamed Hechmi El Ouni ◽  
Khalid Mohamed Khedher
Keyword(s):  
Experimental Investigation ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Self Compacting Concrete ◽  
Pozzolanic Materials ◽  
Passing Ability ◽  
Marble Waste

AbstractSelf compacting concrete (SCC) is special type of concrete which is highly flowable and non-segregated and by its own mass, spreads into the formwork without any external vibrators, even in the presence of thick reinforcement. But SSC is also brittle nature like conventional concrete, which results in abrupt failure without giving any deformation (warning), which is undesirable for any structural member. Thus, self-compacting concrete (SCC) needs some of tensile reinforcement to enhance tensile strength and prevent the unsuitable abrupt failure. But fiber increased tensile strength of concrete more effectively than compressive strength. Hence, it is essential to add pozzolanic materials into fiber reinforced concrete to achieve high strength, durable and ductile concrete. This study is conducted to assess the performance of SCC with substitutions of marble waste (MW) and coconut fiber (CFs) into SCC. MW utilized as cementitious (pozzolanic) materials in percentage of 5.0 to 30% in increment of 5.0% by weight of binder and concrete is reinforced with CFs in proportion of 0.5 to 3.0% in increment of 0.5% by weight of binder. Rheological characteristics were measured through its filling and passing ability by using Slump flow, Slump T50, L-Box, and V-funnel tests while mechanical characteristics were measured through compressive strength, split tensile strength, flexure strength and bond strength (pull out) tests. Experimental investigation show that MW and CFs decrease the passing ability and filling ability of SCC. Additionally, Experimental investigation show that MW up to 20% and CFs addition 2.0% by weight of binder tend to increase the mechanical performance of SCC. Furthermore, statistical analysis (RSM) was used to optimize the combined dose of MW and CFs into SCC to obtain high strength self-compacting concrete.

scholarly journals Microstructural characterization and mechanical performance along the thickness of electron beam welded stabilized AISI 321 stainless steel

10.30544/592 ◽  
2021 ◽  
Author(s):  
Ajay Sharma ◽  
Vineet Prabhakar ◽  
Sandeep Singh Sandhu
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Electron Beam ◽  
Impact Toughness ◽  
Weld Metal ◽  
Weld Joint ◽  
Electron Beam Welding ◽  
Mechanical Performance ◽  
Structure Property ◽  
Aisi 321

The Electron Beam welding (EBW) process was employed to fabricate 18 mm thick fully penetrated butt welds of AISI 321 stainless steel. Nail shaped weld wide at the top and narrow at the bottom was obtained. Characterization of the weld joint was carried out using optical microscopy, scan electron microscopy, X-ray diffraction, microhardness, impact toughness test and tensile strength test. The microstructure of the weld metal was found to be free from defects like cracks porosity etc. The weld metal consisted of the primarily austenitic matrix with skeletal and vermicular morphology of δ-ferrite by the side of the grain boundaries. Carbides of Cr and Ti were found in the weld metal after the thermal aging treatment of 750°C for 24 hours as reveled by the XRD analysis. The tensile strength study revealed a maximum strength of 575 MPa at the root of the weld joint in the as-welded state. The maximum impact toughness of 129.3 J was obtained in the top section of the weld in the as-welded condition. The results in terms of structure-property correlaterelationship. This study recommends the effectiveness of EBW for joining 18 mm thick AISI 321.

scholarly journals Correlation between Microstructure and Mechanical Properties of Heat-Treated Ti–6Al–4V with Fe Alloying

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 854 ◽  
Author(s):  
Yongwei Liu ◽  
Fuwen Chen ◽  
Guanglong Xu ◽  
Yuwen Cui ◽  
Hui Chang
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Phase Interface ◽  
High Strength ◽  
High Plasticity ◽  
High Aging Temperature ◽  
Microstructure And Mechanical Properties

The microstructure and mechanical properties of a newly developed Fe-microalloyed Ti–6Al–4V titanium alloy were investigated after different heat treatments. The volume fraction and the morphological features of the lamellar α phase had significant effects on the alloy’s mechanical performance. A dataset showing the relationship between microstructural features and tensile strength, elongation, and fracture toughness was developed. A high aging temperature resulted in high plasticity and fracture toughness, but relatively low strength. The high strength favored the fine α and the slender β. The high aspect ratio of lamellar α led to high strength but low fracture toughness. The alloy with ~84 vol % α exhibited the highest strength and lowest fracture toughness because the area of its α/β-phase interface was the highest. Optimal comprehensive mechanical performance and heat-treatment procedures were thus obtained from the dataset. Optimal tensile strength, yield strength, elongation, and fracture toughness were 999 and 919 MPa, 10.4%, and 94.4 MPa·m1/2, respectively.

Mechanical Properties and Applications of Carbon Nanotubes

2011 ◽  
Vol 295-297 ◽  
pp. 1516-1521 ◽  
Author(s):  
Li Bao An ◽  
Li Jia Feng ◽  
Chun Guang Lu
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Experimental Measurements ◽  
Reinforced Composites ◽  
Mechanical Behaviors ◽  
Theoretical Predictions

This paper presents a review of current research, both theoretical predictions and experimental measurements, on the mechanical properties of carbon nanotubes (CNTs). The emphasis has been given to the tensile strength and Young’s modulus. Deformabilities including buckling, bending, and twisting are also examined. The predicted and measured values of mechanical behaviors of CNTs are compared and an analysis on the variation of the values is made. The challenges facing the research of mechanical properties of CNTs are stated. CNT reinforced composites are involved as well in the paper. A thorough understanding of the properties of CNTs helps exploring full applications of this unique group of materials.

Mechanical Performance of Paper Pulp and Wood Glue Composite

2017 ◽  
Author(s):  
Daniel M. Madyira ◽  
Takalani Mabirimisa ◽  
Tien-Chien Jen
Keyword(s):  
Tensile Strength ◽  
Composite Material ◽  
Ultimate Tensile Strength ◽  
Mechanical Performance ◽  
High Strength ◽  
Fiber Content ◽  
Pulp Fiber ◽  
Paper Pulp ◽  
Recycled Paper ◽  
Future Work

Due to depleting natural resources, it is necessary to develop eco-composite materials that are fabricated from sustainable and inexpensive materials such as recycled paper or cellulose-based materials. Such materials are required to meet the mechanical performance at par with traditional materials. The main aim of this study was to investigate the mechanical performance of a composite material fabricated from paper pulp and polyvinyl acetate (wood glue). It is expected that a high strength composite material may be achieved by varying the amount of paper-pulp fiber fraction from 7.5%, 10%, 20%, 30%, 40%, 50% to 60% weight. A tensile test was conducted and it was found that an increase in fiber content on the fabricated composite resulted in an increase in ultimate tensile strength and a decrease in corresponding strain. Furthermore, the material becomes more brittle at higher fiber content and conversely, more ductile at lower fiber content. The ultimate tensile strength was found to be 7.69 MPa at 60% w.t fiber and the minimum tensile strength was 0.12 MPa at 0% w.t fiber. There were no signs of fiber content limit observed in the obtained results. It was concluded that a composite of moderate strength was produced and future work is required in order to fully understand how the composite behaves at different loading conditions. However, an optimum fiber content limit will have to be determined.

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