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Mechanical performance parameters such as the fatigue strength, tensile strength, ductility and Young's modulus of newly developed Ti-29Nb-13Ta-4.6Zr, referred to as TNTZ, can be improved considerably by microstructural control via thermomechanical processing. Thermomechanical processing including severe cold wire drawing can generate functionalities such as super elasticity in TNTZ. The abovementioned improvement in the mechanical performance and functionality of TNTZ is associated with its nanosize structure. The cytotoxicity of TNTZ is very low and equivalent to that of pure titanium. It is expected that TNTZ will be used as a structural biomaterial.

In the present paper, the microstructure and tensile properties of Al–Mg–Si alloy irradiated with 2 MeV protons for 5, 10, 20, and 40 mins at 300 K are investigated. The microstructure of irradiated specimens, observed using metallurgical microscope, shows that aspirates are emitted out from the surface of irradiated specimens, which take the form of clusters and/or precipitates with increase of exposure time. The tensile behavior of irradiated specimens was investigated using universal testing machine and compared with that of unirradiated one. The yield stress, ultimate tensile stress and % elongations remain unchanged after 5 and 10 mins of irradiation. However with an increase of irradiation time up to 20 mins, an increase in yield stress, ultimate tensile stress and decrease in % elongation was observed. With further increase of exposure time to 40 mins, the increase in yield stress and decrease in plasticity became more prominent. The results of stress relaxation tests performed during the tensile deformation have also been presented. The XRD analysis reveals that the microstructural changes controlling the tensile properties in irradiated samples appear to be physical rather than chemical.

The relationship between microstructure and mechanical properties in cast aluminum alloys is complex and is strongly affected by the casting process conditions and melt handling practices. The aim of the current work is to understand the critical interactions between material microstructure, mechanical properties and process quality in the development of high performance aluminum alloys. The mechanical properties were investigated and correlated with microstructural features such as porosity, Fe-rich particles, secondary dendrite arm spacing (SDAS) and Si-particle length. The correlation with process quality measures such as bifilm index, density index and sludge factor (SF) were also investigated. The Si-particle lengths were found to explain variation in material strength and ductility which factors such as the bifilm index and porosity could not.

The dependence of tensile properties on the length scale of the dendritic morphology of Al–Cu, Al–Ag and Al–Ag–Cu alloys is experimentally investigated. These alloys were directionally solidified (DS) under a wide range of cooling rates $(Ṫ)$, permitting extensive microstructural scales to be examined. Experimental growth laws are proposed relating the primary dendritic arm spacing, ${\lambda }_1$ to $Ṫ$ and tensile properties to ${\lambda }_1$. It is shown that the most significant effect of the scale of ${\lambda }_1$ on the tensile properties is that of the ternary alloy, which is attributed to the more homogeneous distribution of the eutectic mixture for smaller ${\lambda }_1$ and by the combined reinforcement roles of the intermetallics present in the ternary eutectic: Al₂Cu and nonequilibrium Ag₃Al.

A7N01 aluminum alloy is widely used in rail transit industry due to its excellent comprehensive mechanical properties. However, due to its sensitivity to stress corrosion cracking (SCC), especially in hydrogen-containing moisture environment, the mechanical properties of hydrogen-charged A7N01 aluminum alloy friction stir welding (FSW) joints were tested through the tensile testing machine. The scanning electron microscopy (SEM) was used to study the tensile fracture morphology. The results indicate that the ductility and tensile strength loss of A7N01 Al alloy FSW joints are large in conditions of charging hydrogen. This is due to the embrittlement of the material caused by hydrogen infiltrating into the grain boundary of the aluminum alloy material.

SUS301L-MT (MT-middle tensile) stainless steel is widely used in metro structures due to its excellent mechanical properties and corrosion resistance. However, since steel is metastable, hydrogen-sensitive deformed martensite may easily form during cold rolling, which affects the hydrogen embrittlement behavior of the steel. In this paper, tensile tests were carried out after electrochemical hydrogen charging. Fracture morphology and microstructure analysis were conducted to investigate the hydrogen embrittlement behavior. The results showed that as charging current density increased, the strength and elongation loss got greater. The most deteriorated sample had strength loss of 7.11% and the elongation loss reached 25.94%. The fracture of charged sample showed three regions including tough zone, transition zone (TZ) and brittle fracture zone (BFZ). The side surface was covered with microcracks, as a result of the dissolved hydrogen atoms accumulated in the stress concentration regions on the surface of the sample, forming local high pressure and promoting plastic deformation. Martensite was sensitive to hydrogen, which weakened the atomic bonding force. Hydrogen embrittlement caused the surface of the SUS301L-MT stainless steel to become brittle and finally brittle fracture occurred.

Selective laser melting (SLM)-fabricated AlSi10Mg parts were heat-treated under vacuum to eliminate the residual stress. Microstructure evolutions and tensile properties of the SLM-fabricated parts before and after vacuum annealing treatment were studied. The results show that the crystalline structure of SLM-fabricated AlSi10Mg part was not modified after the vacuum annealing treatment. Additionally, the grain refinement had occurred after the vacuum annealing treatment. Moreover, with increasing of the vacuum annealing time, the second phase increased and transformed to spheroidization and coarsening. The SLM-produced parts after vacuum annealing at 300${}^{\circ }$C for 2 h had the maximum ultimate tensile strength (UTS), yield strength (YS) and elongation, while the elastic modulus decreased significantly. In addition, the tensile residual stress was found in the as-fabricated AlSi10Mg samples by the microindentation method.

Samples of pure zirconium (Zr) were irradiated by 18 MeV helium (He${}^{+}$) ions in the dose range 0.00162–0.0324 dpa at 373 K by using Cyclotron accelerator. The atomic force microscopy (AFM) results indicated an increase in average surface roughness of Zr by increasing the irradiation dose. The AFM images revealed nucleation and growth of nano- and micro-size hillocks at lower doses (0.00162–0.00324 dpa), whereas formation of a volcano-like cavities and craters was observed within these hillocks by increasing the radiation dose from 0.00324 to 0.0324 dpa. The high-resolution X-ray diffraction (XRD) results showed a variation in the intensities and positions of the diffraction peaks after the irradiation. The transmission electron microscopy (TEM) results reported a significant decrease in the grain size after the He${}^{+}$ irradiation. The values of grain size, calculated using the TEM, were found to be in good agreement with the crystallite size calculated using the XRD analysis. The yield stress (YS) was increased by increasing the irradiation dose up to 0.0162 dpa, however, the YS exhibited a decreasing trend with a further increase of the dose. The changes in YS were elucidated by grain size reduction and localized heating at higher doses.

In this work, the Metal Inert Gas (MIG) welding process is used for depositing the Inconel 718 over the base substrate of Stainless steel 321. The optimal welding conditions like 50% overlap, Direct Current (DC) plus mode with a pulse on time (1–5 s), frequency (0.25–1 Hz), peak current (120 A), base currents (60% of peak current), and speed (150–350 mm/min) are used for the successful hard-facing. The quality of the hard-facing is analyzed by conducting microstructural studies, tensile tests, microhardness, wear behavior, and electrochemical studies. Post-processing for wear and electrochemical studies is done by Scanning Electron Microscope SEM–EDX analysis. Microstructural studies revealed the presence of columnar dendrites and equiaxed at the top of the hard-faced layer. Hard-faced layer depicts the highest ultimate tensile strength of 772 N/mm² with an elongation of 31.50% due to the support of Nickel components. The presence of the voids and dimples is identified from the SEM fractography. The maximum hardness value of 212 HV${}_{0.5}$ is measured at the top of the hard face layer. The microhardness of the hard-faced layer increased by 17.77% higher than its base substrate. Because of the hard precipitates and higher microhardness made by the weld thermal cycle, the hard-face layer showed maximum Co-efficient of Friction (CoF) of 0.540. Debris and grooves are found with the SEM examination of the wear specimens. Higher impedance offers better corrosion resistance to the hard-faced layer Inconel 718. The EDX analysis confirms the presence of Chromium, Molybdenum, and Niobium contents at the hard-faced layer. These elements silently support better corrosion resistance compared to the base substrate of Stainless steel 321.

The objective of the current study is to elucidate the influence of freeze storage on the tensile properties of tendons by testing specimens at numerous adjacent durations to eliminate the influence of biological variation and experimental errors. Chicken flexor digitorum profundus tendons were stored intact in the digits at -20°C and specimens were tensile tested at 33 durations over 360 days. Scanning electron microscopy was done on fresh specimens and specimens freeze-stored for 30, 233 and 427 days to investigate microstructure change after freeze storage. The tensile properties of tendons, as represented by ultimate tensile strength, strained at ultimate tensile strength. The elastic modulus did not deviate significantly (p>0.01) after freeze storage while the collagen fiber density of specimens stored for 233 and 427 days decreased with porosity growth. In contrast, no obvious microstructure difference was observed between fresh tendons and tendons stored for 30 days. These findings suggest that the postmortem degradation incurred a minor effect on the structural integrity of the tendons and therefore did not affect the overall tensile properties. We conclude that freeze storage at -20°C does not alter the tensile properties of tendons for as many as 360 days.

We report on the electrospinning method to synthesize and characterise chitosan membranes reinforced by halloysite nanotubes (HNTs). The synthesis process addressed two levels of HNTs concentration, i.e., 2 and 5 wt.%. Tensile testing was carried out to determine the strength (σ), strain (ε) at σ and elastic modulus (E) of the membranes. Tensile test data revealed that the membranes reinforced with 5 wt.% HNTs yielded the highest E (0.153 ± 0.02 GPa) and strength (22.53 ± 8.57 MPa). Electron micrographs of the fractured surfaces showed uniform dispersions of HNTs in the chitosan matrix. Infrared spectra indicated interactions between chitosan and inner and outer surfaces of HNTs. Thermogravimetric analysis demonstrated an increase in thermal stability with the addition of HNTs. Membranes immersed in simulated body fluid system for 28 days revealed the formation of dense apatite blocks with the addition of HNTs. Surface roughness increased with the addition of HNTs resulted a rise in degree of contact angle.

Herein, a method was proposed for testing the dynamic tensile properties of a sports medicine suture and investigating the fatigue properties and elongation of the suture after a fatigue test. A test device was designed to test the dynamic tensile properties of sutures. The endurance limit of Nos. 1 and 4 sutures, which were used for laboratory comparisons, was $23.7\pm 1.4$N and $68.5\pm 2.3$N and the elongation rate was $3.3\%\pm 0.6\%,4.0\%\pm 0.3\%$, respectively. Furthermore, the Z-score, which is the offset divided by the standard deviation, was $<2$. The proposed test method is accurate and the repeatability is satisfied, making it suitable for determining the dynamic tensile properties of sutures. It is used as an industry standard to provide technical support for supervising sports medicine sutures.

The classical MD (Molecular Dynamics) method was used to simulate the tension of three kinds of C₂₄₀ isomers, i.e., C₂₄₀ nanotube, chain-like 4C₆₀ fullerene polymer and peanut-like 4C₆₀ fullerene polymer. Then, the semi-empirical PM3 method was used to calculate their electronic structures under tension. Lastly, according to the calculated results, their differences in tensile mechanical properties, as well as the change of their FMO (Frontier Molecular Orbital) energy during tension, were discussed. It is shown that: (1) the load-support capability of the C₂₄₀ molecules has the order of C₂₄₀ nanotube > peanut-like 4C₆₀ polymer > linear 4C₆₀ polymer, but their deformation-support capability has the contrary order, (2) of the C₂₄₀ isomers, the C₂₄₀ nanotube has the best chemical stability, and the chain-like 4C₂₄₀ molecule has the worst one, and (3) the deformed C₂₄₀ isomers have narrower energy-gap between their LUMO and HOMO, and higher chemical activity.

Carbon nanotube (CNT) yarns were drawn from the web found on the CVD furnace wall. The yarns were twisted and their tensile behavior was investigated through in-situ SEM and regular tensile tests. The mechanisms involved in the CNT yarn deformation were identified. The twisted CNT yarns were found to have a good ability to stretch and deform and featured a diameter-dependent strength.

Boron nitride nanotubes (BNNTs) are of immense importance due to their many interesting functional features, notably biocompatibility and piezoelectricity and dominant mechanical strength as compared to carbon nanotubes (CNTs). The reliable implementation of these structures in an application is inherently related to its mechanical characteristics under external loads. The presence of defects in these structures severely affects the tensile properties. The effect of presence of point, line and Stone–Wales (SW) defects on the tensile behavior of BNNTs is systematically investigated by applying reactive force fields in molecular dynamics (MD) framework. Reactive force fields effectively describe the bond breaking and bond forming mechanism for BNNTs that are important for a practical situation. The Young's modulus of single-walled (10,0) BNNTs of length 100 nm has been found to be nearly 1.098 TPa, in good agreement with the available reports. The presence of defects has been shown to significantly reduce the tensile strength of the tube, while the number and separation of the defects effectively contribute to the percentage reduction. In addition, the effect of tube diameter and also the initial temperature are observed to strongly influence the tensile characteristics of BNNTs, indicating increased auxetic behavior than CNTs.

The effect of storage on physico-chemical properties of non-irradiated natural rubber and radiation vulcanized natural rubber (RVNR) were evaluated. The rubber films were stored under two different conditions, namely in open air and sealed polyethylene bags. The antioxidant, tris(nonylated phenyl) phosphite (TNPP) was used for preventing degradation of RVNR films. Gel content, cross-link density, tensile strength at break and 500% elongation of rubber films were measured. The results show that the retention (%) of tensile properties of rubber films with TNPP is higher than that of rubber films without antioxidants. The rubber films stored in polyethylene bags also show better retention of tensile properties than those of rubber films stored in open air.

The gradient design of a fine grain structure on the surface and coarse grain structure in the substrate gives nano metallic materials both high strength and plasticity. Inspired by the concept of gradient design of grain sizes in materials science, this paper shows the design of the gradient Voronoi polygonal honeycomb structure. The quasi-static uniaxial tensile deformation processes of both, gradient and uniform, Voronoi structures were studied and it was found that the gradient design of the honeycomb cell size greatly improves the tensile property and strain energy storage of the Voronoi structure.

The powder of the micro Al and variant volume fractions of nano Al₂O₃ were milled by a high energy planetary ball-mill. By milling, a homogenous distribution of nano Al₂O₃ particles in the metal matrix were developed. Then the milled powder was cold compressed and sintered at 545°C for one hr. The mold and the sintered sample hold in a furnace until the temperature reached 545°C. Then the hot 27mm diameter sample was extruded to 6mm diameter. From the extruded specimens, tensile, hardness and microstructure of the prepared specimens were determined. By these tests the effect of milling time, the percent of nano-particles and the microstructure were evaluated. The hardness and tensile behaviors of aluminum matrix composites reinforced with nano Al₂O₃ particulate have been found to increase remarkably with the volume fraction of the reinforcement.

Manila hemp fibers are separated to several sequent fragments from single fiber. The tensile strength of each fiber fragments and their epoxy composite are measured, followed by scanning electronic microscopic (SEM) analysis. The results show that the tensile strength of fiber fragments is almost constant along fiber. For composite, the tensile strength first increases and then decreases at the position near to root. The Young's modulus presents increasing with location from root to top for fiber and composite. Microstructure analysis indicates that the difference of tensile properties between fiber fragments derive from the difference of fiber diameter.

As only a few studies have been reported so far, mechanical properties of stress fibers (SF) have poorly been understood, mainly due to difficulties with experimental technique. A previous study in our laboratory has described development of a micro-tensile tester to measure tensile properties of single SF chemically isolated from vascular smooth muscle cells (VSMC). Tensile tests were performed at a single strain rate of 0.02 s^-1. In this study, the strain rate dependency of tensile properties of SF was investigated. The results showed that the initial stiffness of SF at strain rate of 0.01 s^-1, 0.05 s^-1 and 0.1 s^-1 were 0.010 ± 0.004 N/m, 0.006 ± 0.006 N/m, 0.028 ± 0.011 N/m, respectively. Averaged force-strain relationships were found to be almost linear in the physiological strain range of 0.0-0.4 for 0.01 s^-1 and 0.05 s^-1. These linear relationships were consistent with a previous report at a strain rate of 0.02 s^-1. In contrast, the force-strain relationship was nonlinear for the 0.1 s^-1 strain rate. The reason for this difference is unclear, possibly due to a threshold in strain rate between 0.01 s^-1 and 0.1 s^-1. Mechanical properties of SF may be strain rate dependent, particularly having a threshold in the linearity of the force-strain relationships.