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Showing papers on "Tensile testing published in 1976"


Journal ArticleDOI
01 Jun 1976-Nature
TL;DR: In this article, the synthesis of continuous β-SiC fibres by a new process: the conversion of organometallic polymers to inorganic substances was studied, and the transformation process and the structure and mechanical properties of these fibres were studied.
Abstract: MUCH work has been done on preparing heat-resistant silicon carbide materials in fibrous form, since plastics or metals can be reinforced with them to obtain very heat-resistant material of great mechanical strength. SiC whiskers1 are, however, impractical because of their shortness (several mm), their non-uniform diameter and high cost of production. SiC-on-W (ref. 2) and SiC-on-C (ref. 3) filaments have been produced by chemical vapour methods. These coated filaments are more expensive, and the treatment for making such composite materials requires careful control. We report here on the synthesis of continuous β-SiC fibres by a new process: the conversion of organometallic polymers to inorganic substances. We have studied the transformation process and the structure and mechanical properties of these fibres.

464 citations


Journal ArticleDOI
L. Remy1, André Pineau1
TL;DR: In this article, the influence of various deformation modes on the tensile mechanical properties of various alloys has been examined using transmission electron microscopy and X-ray diffraction analysis and it has been found that low temperature plastic deformation induces the γ (f.c.) → ϵ (h.c.p.) martensitic transformation.

240 citations


Journal ArticleDOI
TL;DR: In this paper, as-quenched and tempered martensite in an Fe-0.2 pct C alloy were subjected to tensile testing and structural characterization by light and transmission electron microscopy.
Abstract: As-quenched and tempered martensite in an Fe-0.2 pct C alloy were subjected to tensile testing and structural characterization by light and transmission electron microscopy. The light temper, 400°C-l min, did not change packet morphology, but did reduce dislocation density, coarsen lath size and cause the precipitation of carbides of a variety of sizes. The yield strength of the as-quenched martensite was strongly dependent upon packet size according to a Hall-Petch relationship, but tempering significantly diminished the packet size dependency, a result attributed to packet boundary carbide precipitation and the attendant elimination of carbon segregation present in the as-quenched martensite because of autotempering. Examination of thin foils from strained tensile specimens showed that a well-defined cell structure developed in the as-quenched martensite, but that the random distribution of jogged dislocations and carbide particles produced by tempering persisted on deformation of the tempered specimens.

206 citations


Journal ArticleDOI
TL;DR: Uniaxial tensile tests were performed on standardised longitudinal specimens of bovine compact bone at strain rates from 5·3×10−4 to 237 s−1 to demonstrate highly significant positive correlations betweenultimate strength and strain rate, and between ultimate strength and density.
Abstract: Uniaxial tensile tests were performed on standardised longitudinal specimens of bovine compact bone at strain rates from 5·3×10−4 to 237 s−1. After testing, the microstructure and dry density of each specimen was determined. The test results demonstrated highly significant (P<0·01) positive correlations between ultimate strength and strain rate, and between ultimate strength and density. A highly significant negative correlation between ultimate strength and the extent of secondary Haversian remodelling was also found. The modulus of elasticity showed similar correlations with the test parameters. A multiple linear-regression analysis was used to derive equations for the ultimate strength and modulus as functions of strain rate and microstructure. The regression analyses accounted for 86% of the variance in strength and 50% of the variance in modulus. The extent of secondary Haversian remodelling showed a significant (P<0·01) negative correlation with the energy-absorption capacity. Strain rate also had a significant effect on the energy-absorption capacity. Specimens tested at higher strain rates generally absorbed more energy during failure. There was no evidence of a critical velocity at which the energy absorption capacity attained a maximum. The test results correlate well with previous studies of the mechanical properties of compact bone.

178 citations


Journal ArticleDOI
TL;DR: In this article, it was found that a high purity Al-6%Zn-3%Mg alloy becomes embrittled if pre-exposed to moist gases prior to tensile testing.

168 citations


Journal ArticleDOI
TL;DR: In this article, the area of the true stress/true strain diagram determined under tensile test conditions is equal to the energy absorbed per unit volume at the point of fracture, where the critical specific fracture energy (W c ) characteristic of the material has been absorbed whereby the proportionality law of notched specimens can then be derived.

145 citations


Journal ArticleDOI
TL;DR: The recorded load time histories showed marked nonlinearities in the stress strain behavior of some specimens including plastic deformation and strain hardening effects, thus emphasizing that the fracture energy alone is an incomplete representation of the tensile impact behaviour of bone.

43 citations


Journal ArticleDOI
TL;DR: In this paper, a constant tensile stress creep testing machine is described, which makes it possible to keep the stress constant within 0.1% up to a strain 0.45, assuming the volume of the specimen does not change during the test.
Abstract: A new constant tensile stress creep testing machine is described. The machine makes it possible to keep the stress constant within 0.1% up to a strain 0.45, assuming the volume of the specimen does not change during the test. The cam profile has been solved for specimen gage lengths of 50.0, 35.0, and 25.0 mm. The static counterbalance of the loading system ensures its high sensitivity, which, together with the minimizing of frictional forces, offers the possibility for the tensile stress to be accurately defined. Erratum to this paper appears in 4(4)

41 citations


Journal ArticleDOI
TL;DR: In this article, the authors identify sources of misalignment in uniaxial tensile testing, recognize the effects of misalignments on tests results, evaluate the extreme surface bending strains and stresses, and become acquainted with some techniques for reducing misalignment to within tolerable limits.
Abstract: Uniaxial tensile testing is a method used throughout the world to measure the strength and ductility of materials. An important aspect of uniaxial tensile testing which often goes unrecognized is test system alignment. Poor alignment can significantly influence test results at small strains, especially the fracture strengths of materials in a brittle state. The purpose of this review paper is to enable a reader to identify sources of misalignment, recognize the effects of misalignment on tests results, evaluate the extreme surface bending strains and stresses, and become acquainted with some techniques for reducing misalignments to within tolerable limits. Numerous references are made to the literature which describes how misalignment may be influenced by couplings in the loading train and by specimen design. A quantitative assessment of the devices and techniques discussed in this literature is made in those cases where sufficient data have been provided. The literature surveyed indicates that misalignment in carefully designed and precisely machined testing systems ranges between 3 and 15% bending. The need for reporting the misalignment at which a given test result is obtained is pointed out.

41 citations



Journal ArticleDOI
TL;DR: In this paper, the anneal hardening behavior of a Cu-16 at. pct. alloy was investigated by tensile testing, measurement of Young's modulus and electrical resistivity, and electron microscopy.
Abstract: The anneal hardening behavior of a Cu-16 at. pct. Al alloy was investigated by tensile testing, measurement of Young’s modulus and electrical resistivity, and electron microscopy. It was shown that three main stages of annealing processes can be distinguished. Stage 1 atT ≤ 150°C is characterized by vacancy annihilation and short-range diffusional processes giving rise to three successive, low maxima in yield and tensile strength. Substages in this temperature range are also evident from resistivity measurements. Stage 2 at 150 ≲ 275°C is essentially associated with solute segregation to dislocations giving rise to the main increase in flow stress. In Stage 3 at 725 ≤T ≤ 350°C recrystallization takes place.

Journal ArticleDOI
TL;DR: In this paper, the authors measured tensile properties of injection and compression molded ABS, terpolymer of acrylonitrile, butadiene, and styrene, as a function of aging time at 40 to 90°C.
Abstract: Tensile properties of injection and compression molded ABS, terpolymer of acrylonitrile, butadiene, and styrene, were measured as a function of aging time at 40 to 90°C. Both air and nitrogen atmospheres were employed to separate the oxidative and thermal effects. Results demonstrate that tensile elongation is drastically reduced by oven aging at 50 to 90°C, even when a nitrogen atmosphere is employed. Aging in air causes changes in the infrared spectra of ABS and these changes can he monitored in thick samples using the frustrated multiple internal reflection (FMIR) technique. The FMIR technique also provides information on the changes in polybutadiene distribution near the surface of molded parts. The loss of tensile elongation after oven aging is attributed to annealing of the glassy styrene-acrylonitrile matrix. This is supported by differential scanning calorimetry. The tensile elongation is found to he recoverable by reheating to processing temperatures.

Journal ArticleDOI
TL;DR: In this paper, the annealing characteristics of ultraoriented high-density polyethylene fibers have been studied using differential scanning calorimetry, thermomechanical analysis, and tensile testing.
Abstract: The annealing characteristics of ultraoriented high‐density polyethylene fibers have been studied using differential scanning calorimetry, thermomechanical analysis, and tensile testing. The melting point of unannealed fibers was estimated to be 130 °C using a 10 °C min −1 heating rate. Fiber annealing between 126 and 132 °C split the melting endotherm into two peak melting at 132 and 139 °C. The weight fraction of fiber which had reorganized to the lower melting point increased with annealing time, finally attaining a constant value. However, annealing of laterally constrained fibers below 136 °C did not result in structural changes as detected by calorimetry. Melting‐point variations with heating rates≳0.625 °C min−1 indicated the equilibrium melting point of the unconstrained fiber at zero heating rate as 138 °C, while a similarly extrapolated value using heating rates <0.625 °C was ∼132 °C. The linear expansion coefficients rapidly increased near 132 °C and were attributed to the structural reorganization detected by calorimetry. Fiber annealing markedly decreased the tensile modulus from 50 GPa towards the 1 GPa observed for the unoriented polyethylene. The annealing behavior was consistent with the thermal instability associated with the anisotropy of the surface free energies of the ultraoriented crystalline fibers as well as sources of melting‐point reduction such as defects.

01 Apr 1976
TL;DR: In this article, a combined theoretical and experimental investigation was conducted to assess the suitability of the 10 deg off-axis tensile test specimen for the intralaminar shear characterization of uni- directional composites.
Abstract: : A combined theoretical and experimental investigation was conducted to assess the suitability of the 10 deg off-axis tensile test specimen for the intralaminar shear characterization of uni- directional composites. Composite mechanics, a combined-stress failure criterion, and a finite element analysis were used to determine theoretically the stress-strain variation across the specimen width and the relative stress and strain magnitudes at the 10 deg plane. Strain gages were used to measure the strain variation across the specimen width at specimen midlength and near the end tabs. Specimens from Mod-I/epoxy, T-300/epoxy, and S-glass/ epoxy were used in the experimental program. It was found that the 10 deg off-axis tensile test specimen is suitable for intralaminar shear characterization and it is recommended that it should be considered as a possible standard test specimen for such a characterization. (MM)

01 Jan 1976
TL;DR: In this article, the authors investigated the load strain behavior and ultimate tensile strength for both plain and polymer impregnated concrete cylinders subjected to splitcylinder load method and double-punch load method.
Abstract: This paper investigates the load strain behavior and ultimate tensile strength for both plain and polymer impregnated concrete cylinders subjected to split-cylinder load method and double-punch load method. These two testing techniques have been used frequently in practice for the determination of tensile strength of concrete materials. Behavior and strength variations in the two tests are described.

Journal ArticleDOI
TL;DR: The possibility of bearing Babbitt damage arising from transient and steady-state liquid tensile stresses is postulated in this article, where a critical eccentricity ratio has been suggested below which, for a particular clearance, a tensile stress may be generated.
Abstract: Tensile stresses of 740 kN/m2 have been observed in the oil film of a steadily loaded journal bearing. A critical eccentricity ratio has been suggested below which, for a particular clearance, a tensile stress may be generated.An extensive literature survey indicates the sensitivity of the liquid's tensile strength to such factors as gas content, viscosity, particle content and the surface finish at the liquid/bearing material interface.It is suggested that previously attempted observations of liquid tensile stresses in journal bearings may have been limited by the configuration of the pressure-measuring device.The possibility of bearing Babbitt damage arising from transient and steady-state liquid tensile stresses is postulated.

Journal ArticleDOI
K. Boustany1, R.L. Arnold1
TL;DR: In this article, the tensile properties of the composite are precisely related to the fiber stiffness and stiffening action of the fibers, which provides a harder material with greatly reduced solvent swelling characteristics compared to the matrix rubber.
Abstract: Composites produced by dispersion of selected short cellu lose fibers in elastomeric matrices are useful engineering materials. These fibers are pre-treated to provide dispersion in conventional mixing equip ment while minimizing fiber damage, and to give bonding to utilize the rubber reinforcing ability of the fiber. In the uncured composite, the fibers contribute higher green tensile strength, and almost no die swell on extru sion. The vulcanized composites show a monotonic increase in Young's Modulus and a decrease in ultimate elongation with increasing fiber load ing. As with many composites, the tensile strength is less than the matrix strength at very low fiber loading, but at higher fiber levels the matrix is reinforced and the composite tensile strength exceeds the matrix strength. The stiffening action of the fibers provides a harder material with greatly reduced solvent swelling characteristics compared to the matrix rubber. Finally, the tensile properties of the composite are precisely related ...

Journal ArticleDOI
TL;DR: In this paper, the correlation between tensile properties (yield strength, ultimate tensile strength and uniform strain) and indentation hardness is studied for two types of Al-Zn-Mg alloys.
Abstract: The correlations between tensile properties (yield strength, ultimate tensile strength and uniform strain) and indentation hardness are studied for two types of Al-Zn-Mg alloys. The reasons why Tabor's equations do not well fit the experimental data when the strain-hardening coefficient is larger than 0.3 are discussed. New equations for the determination of tensile properties from hardness measurements are theoretically derived and found to be in excellent agreement with the experimental data for Al-Zn-Mg alloys. The equations areT u=(H v/c 2)[4.6(m−2)] m−2 and σy=(H v/C 2)1-(3−m> ) +25 (m−2), whereT u andσ y are ultimate tensile strength and yield strength,H v is Vicker's hardness number,m is Meyer's hardness coefficient,E is Young's modulus,c 2 is a constant about 2.9 in magnitude. In these equationsT u,σ y,H v andE are all expressed in kg mm−2.

01 Jun 1976
TL;DR: In this article, the authors developed a simple test to design bituminous concrete mixtures for fatigue resistance and found that indirect tensile test results correlate with the stress-fatigue life curve under the constant stress fatigue test mode and the strain-fraction fatigue life curve in the constant strain fatigue testmode.
Abstract: The objective of this project was to develop a simple test to design bituminous concrete mixtures for fatigue resistance. Included are two literature reviews: (1) current fatigue testing procedures, and (2) simple test methods that offer possibilities for fatigue prediction. Seven bituminous concretes representing five areas of the United States were tested by a beam fatigue apparatus and several selected simple test methods. Correlations were performed between fatigue results and simple test results, and the best correlations were obtained with the indirect tensile test. Indirect tensile test results correlate with the stress-fatigue life curve under the constant stress fatigue test mode and the strain-fatigue life curve under the constant strain fatigue test mode. The main conclusion is that the indirect tensile test can be used to predict the fatigue characteristics of bituminous concretes and a simple test method is recommended.

Journal ArticleDOI
TL;DR: In this paper, a comparative study of the fracture morphology of 15-denier nylon 66 filament subjected to various modes of deformation was conducted, including simple tensile, simple torsion, cyclic torsional fatigue, and flex fatigue.
Abstract: This investigation deals with the comparative study of the fracture morphology of 15-denier nylon 66 filament subjected to various modes of deformation. The modes of deformation included in the study are simple tensile (low and high rate of extension, low temperature, and room temperature), tensile fatigue, simple torsion, cyclic torsion, flex fatigue, and various combinations of these simple modes. The tensile breaks (dry and in liquid nitrogen) were obtained by extending the fiber to break on an Instron tensile tester. Tensile breaks at extremely high rates of extension were accomplished by the use of a device based on the principle of the “relaxation catapult,” Fiber-fracture experiments in tensile fatigue, simple torsion, and bending fatigue were carried out by the techniques developed at UMIST. In order to obtain fiber breaks in cyclic torsional fatigue, a special apparatus was constructed which was capable of imposing repeated torsion with a high degree of twist at a rate of approximately 5Hz. The b...

Patent
29 Apr 1976
TL;DR: An automatic tensile test apparatus includes an output device which supplies an elongation data of the specimen to the data processor in cooperation with means to optically detect said elongation, means to electrically detect the tension of said specimen, and a device which detects the break of a specimen as discussed by the authors.
Abstract: An automatic tensile test apparatus includes an output device which supplies an elongation data of the specimen to the data processor in cooperation with means to optically detect said elongation, means to electrically detect said tension of said specimen and supply it to the data processor, and a device which detects the break of said specimen. Said output device generates a signal for causing the elongation strain and the tensile stress to be loaded into the data processor so as to correspond to each other. The break detector provides a break signal to the output device and the tension detecting means.

Journal ArticleDOI
TL;DR: In this paper, room temperature tensile testing has been carried out on a number of multifilamentary Nb 3 Sn superconductivity wires and it was shown that filament cracking does not occur until strains approaching 1% have been reached.


Book ChapterDOI
TL;DR: In this paper, the authors describe how homogeneous compression can be obtained, paying particular attention to specimen dimensions and lubrication techniques, and make a comparison of deformation under nonhomogeneous conditions.
Abstract: Testing in compression has several attractive features when compared to the more frequently employed tension test. To take full advantage of these features, it is necessary to obtain deformation that is as close to homogeneous as possible. This paper describes how homogeneous compression can be obtained, paying particular attention to specimen dimensions and lubrication techniques. Comparison is made to deformation under nonhomogeneous conditions. Stress-strain curves obtained in compression for various engineering materials are presented. These curves represent uniform or homogeneous compression. For some metals, there is excellent agreement between the compressive flow curves and those obtained in tension, provided the latter is corrected for necking. However, it is shown that, for high-strength steels, there is not the expected agreement between the compressive and tensile flow curves. The resistance to compressive deformation is greater than to tensile deformation. This effect, termed a strength differential effect, is shown to be independent of the amount of plastic strain. However, it is affected by temperature, since it increases as the temperature is lowered.

Journal ArticleDOI
TL;DR: The multisequence block polymers described in this article contain 7% to 27% silicone consisting of blocks of number-average degree of polymerization 10 to 40, and they are extrudable and injection moldable with only minor changes in color, transparency, and strength properties.
Abstract: Bisphenol fluorenone carbonate–dimethylsiloxane block polymers have been synthesized by interfacial condensation of phosgene with various mixtures of BPF-endcapped silicone oligomers and free BPF or its monosodium salt. The multisequence block polymers described here contain 7% to 27% silicone consisting of blocks of number-average degree of polymerization 10 to 40. Cast films are clear and colorless. Two glass temperatures are evident in each resin, one at about −100°C for the silicone microdomains and one at temperatures as high as 275°C for the polycarbonate matrix. While BPF polycarbonate is brittle, block polymers with as little as 10% silicone yield by shear deformation before breaking. Ultimate elongations are increased by preorientation at silicone contents above 15%. At temperatures far removed from BPF carbonate domain Tg's, both modulus and yield stress decrease with increasing silicone content, independent of block length, in a manner rationalized quantitatively by hard phase–soft phase continuum models. Ultimate tensile elongation, impact toughness, and plane strain stress intensity factors increase with silicone content, through a stress whitening mechanism. At higher silicone contents, shear deformation enhances tensile elongation and impact toughness. Heat distortion temperatures of 200°C or more are achieved. Flame resistance exceeds that of any known nonhalogenated resin. The resins are extrudable and injection moldable with only minor changes in color, transparency, and strength properties. Resins with 15% to 20% silicone can have a balance of properties that makes them attractive as tough, transparent heat- and flame- resistant engineering plastics.

Journal ArticleDOI
TL;DR: In this paper, the relationship between structure and mechanical properties of thin TD-NiCr sheet was studied and it was shown that the elevated temperature tensile, stress-rupture, and creep strength properties are dependent on grain aspect ratio and sheet thickness.
Abstract: A study of the relationship between structure and mechanical properties of thin TD-NiCr sheet indicated that the elevated temperature tensile, stress-rupture, and creep strength properties are dependent on grain aspect ratio and sheet thickness. In general, the strength properties increase with increasing grain aspect ratio and sheet thickness. Tensile testing revealed an absence of ductility at elevated temperatures (T>-1144 K). Significant creep damage, as determined by subsequent tensile testing at room temperature, occurs after very small amounts (<0.1 pet) of prior creep deformation at elevated temperatures (1144≤T≤1477 K). A threshold stress for creep appears to exist. Creep exposure below the threshold stress atT≥1366 K results in almost full retention of room temperature tensile properties.

Journal ArticleDOI
TL;DR: In this paper, an estimate of the ultimate tensile strength of water with data from previously reported isochores obtained using the Berthelot tube method was made, and the agreement with the theoretical values predicted by Temperley's theory was most satisfactory.
Abstract: An estimate is made of the ultimate tensile strength of water with data from previously reported isochores obtained using the Berthelot tube method. The agreement with the theoretical values predicted by Temperley's theory (1947) is most satisfactory.


Journal ArticleDOI
TL;DR: In this paper, superplasticity has been investigated in three carbon-manganese steels with small additions of Nb, V, Al and Ti and the results showed that the strain rate sensitivity did not vary with strain although it was very dependent on strain rate and temperature.
Abstract: Superplasticity has been investigated in three carbon-manganese steels with small additions of Nb, V, Al and Ti. Superplasticity was observed from 800 to 1000°C at strain rates from 0.002 to 0.01 min-1. Strain rate sensitivities above 0.7 have been observed; however elongations to fracture are quite low with a maximum value observed of 184 pct. The strain rate sensitivity did not vary with strain although it was very dependent on strain rate and temperature. Cold work prior to hot tensile testing enhanced the superplasticity in the vanadium steel. The premature failure of these steels with large strain rate sensitivities has been attributed to crack nucleation due to the fine particle network from the Nb and V precipitation.

Journal ArticleDOI
TL;DR: In this article, the effects of coherency strains, modulii differences between matrix and precipitate and antiphase boundary energy are combined to derive two characteristic levels of particle strength.
Abstract: The hardening mechanisms in age-hardening ferritic Fe-Ni-Al-Ti alloys have been investigated using electron microscopy, tensile testing and the application of quantitative theories of strengthening in two phase materials. The level of the strength and its dependence upon aging time have been quantitatively predicted from a model in which the effects of coherency strains, modulii differences between matrix and precipitate and antiphase boundary energy are combined. Two characteristic levels of particle strength are derived in the model from the combination of these effects. The flow stress in the alloy is then determined by the stress to pass through the random array of particles in which two levels of strength exist.