Papers by Keyword: Elongation

Abstract: Experimental studies of the dependence of the deformation ε1max on the strain σ and the relative changes in the width and thickness of the unirradiated and irradiated polytetrafluoroethylene film on the relative elongation are carried out. It was found that these quantities depend essentially on the load. The curves obtained are satisfactorily described by a linear model.

Abstract: The occurrence of superplasticity may be traced to the classic work of Pearson conducted in the U.K. in 1934 when an elongation of 1950% was reported in a Pb-Sn eutectic alloy. Subsequently, much attention in Russia was devoted to this scientific curiosity and this led to the first book on superplasticity written by Prof. A.A. Presnyakov and published in 1964. Later, in 1985, Oscar Kaibyshev established in Ufa the Institute of Problems of Superplasticity of Metals of the Russian Academy of Sciences and this was, and remains to this day, the only institute in the world devoted exclusively to studies of the phenomenon of superplastic flow and the development through superplastic forming of complex-shaped parts. An important development occurred in 1988 with the publication of a classic report by Kaibyshev and co-workers describing the potential for achieving low temperature superplasticity in a metallic Al-Cu-Zr alloy that had been specially processed by severe plastic deformation (SPD) to produce a remarkably small grain size of only 300 nm. This report formed the basis for the later development of SPD processing as a major tool for the production of exceptional grain refinement and as a procedure for achieving large superplastic elongations that cannot be achieved using more conventional processing. This report describes this early work, the subsequent developments and the modern status of superplastic flow in ultrafine-grained metals.

Abstract: The aim of the present work is to study the evolution of microstructure, texture and mechanical properties during drawing of mild steel wire of type F8Z used in the manufacture of welding electrodes TREFISOUD. It was found that the as received wire has a ferritic-pearlitic microstructure corresponding to an isotopic state (without texture). This microstructure is relatively heterogeneous in the wire section. On the other hand, after strong drawing structure appears relatively homogeneous, throughout the section of the drawn wire. Also the deformation process by drawing causes the hardening of wire as a function of deformation with a reinforcing component of the fiber texture <110> // ND (majority), typical for bcc materials. Characterization methods used in this work is: Optical microscopy (OM), Scanning Electron Microscopy (SEM), the Electron Back Scattered Diffraction EBSD, Vickers microhardness and the tensile tests.

Abstract: Indonesia has the most laterite ore reserves in the world. The element originated from the laterite ore is one of the materials in the steel industry. Despite its plentiful of reserves, laterite steel ore has not been used to its maximum potential. This research aims to overview reduction effect on mechanical properties of laterite steel as a result of heated rolling process with various reduction. The reduction variety used in this research were 30%, 40%, 50%, and 60%. Also, the temperature was 980oC. As a result of this research, the increment of reduction followed by the increment of hardness and firmness level of laterite steel. It is proofed by hardness and tensile test. Firmness of the material increased as the reduction increases. The most optimized mechanical properties obtained by 50% reduction, the hardness number was 280.03 HB, tensile strength 620 MPa, elongation 32%, yield 493.33 MPa. Micro structures which formed in this process are ferrite and pearlite phase with very fine pellet size and even pearlite distribution. Fracture types are brittle and ductile fracture with very fine pellet size.

Abstract: This study deals with the effect of high doses of ionizing beta radiation (132, 165 and 198 kGy) on mechanical properties (tensile strength, tensile modulus and elongation) of low and high density polyethylene under thermal loading. The measurement results of this study indicate that with an increasing dose of radiation grows tensile strength and modulus of low and high density polyethylene. For all examined materials were also observed changes in elongation.

Abstract: Additive technologies are replacing the conventional methods of casting and subsequent time-consuming machining because of its high productivity. Resent engineering development in the field of additive manufacturing allows increasing assortment of useful powder materials. Technology of high-speed direct laser deposition (HSDLD) is a one of most perspective new technologies. It allows realizing heterophase process during the manufacturing, which there is process of partial melting of used powder is realized. The product is formed from a metal powder, which is supplied by compressed gas-powder jet directly into the laser action zone, wherein the jet can be as coaxial and as non-coaxial. Ni-based alloys found their application in many industrial areas, mostly there are used engine systems, aircraft and shipbuilding, aeronautics. The unique combination of operational characteristics depending on the type of alloy makes them promising materials. Heating and cooling rates during direct laser deposition determine structure and affect on its properties. Research is focused on structure and phase formation within technological process of HSDLD for Ni-base superalloys. Mechanical tests were carried out on the static tensile test, microhardness was measured. Based on research results the high-speed direct laser deposition technology could be used for manufacturing of products from different Ni-based alloys without subsequent heat treatment.

Abstract: China's existing polymer-modified cement based compounds for waterproofing material standards are used for the tensile strength test and elongation at break test as the test method to evaluate the performance of the product extension. The elongation only reflects the extension ability of product, but cannot indicate the crack bridging ability of the product. In engineering applications, there is a requirement for higher bridging cracks ability of the products. In this paper, 9 samples of polymer-modified cement based compounds for waterproofing material were tested. Crack bridging ability was tested under the standards and methods in DIN EN 14891:2013-07. Tensile strength and elongation at break were tested according to the standards and methods in GB23445:2009. The crack bridging ability test results are between 0 to 2.08mm, in which 5 of them meet the requirements of greater than 0.75mm according to DIN EN14891:2013-07.The tensile strength test results are between 1.13MPa to 3.19MPa, the elongation at break test results are between 4% to 350%.The results show that higher tensile strength and higher elongation at break will have good ability of crack bridging. Samples with better crack bridging ability are close to type III product according to GB23445-2009 which requires tensile strength ≥ 1.8MPa and elongation at break ≥ 30%. Crack bridging ability directly reflects the product’s ability of crack bridging, and is more in line with the actual requirements in engineering applications. It is recommended that the crack bridging ability test method should be adopted in the formulation of China polymer-modified cement compounds for waterproofing material standards.

Abstract: Graphite reinforced bio-based epoxy composites with different particulate fractions of graphite were investigated for mechanical properties such as tensile strength, elastic modulus and elongation at break. The graphite content was varied from 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, 30 wt.% by weight percent in the composites. The results showed that the mechanical properties of the composites mainly depend on dispersion condition of the treated graphite filler, aggregate structure and strong interfacial bonding between treated graphite in the bio-based epoxy matrix. The composites showed improved tensile strength and elastic modulus with increase treated graphite weight loading. This also revealed the composites with increasing filler content was decreasing the elongation at break.

Abstract: Aluminum brass possesses an attractive combination of properties including high strength, high thermal and electrical conductivity, good mechanical workability, excellent corrosion resistance, low susceptibility to stress corrosion cracking. This make it a preferred choice for bimetal strips. The materials for preparing bimetal strips with cold roll bonding should have a good plasticity. In the present work, a Cu-Zn-Al-Ni alloy was proposed and the annealing process for this aluminium brass alloy was studied. The effect of annealing temperature and annealing time on the microstructure and mechanical properties was investigated. The proper annealing parameters were obtained.

Abstract: In view of the phenomenon that the curved duct in anchorage zone of cable-stayed bridges result in non-uniformity of each of steel strand, we analyzed the position change law of the prestressed steel strand in curved duct. Simulating real bridge design, a simple method was proposed to compute non-uniformity level of prestressed steel strand in the process of tensioning. Results showed that the rearrangement caused the additional length difference result in stress non-uniformity of each steel strand. Because each of steel strand cannot participate in force at the same time, the actual elongation value of the tendon is greater than theoretical value.