Papers by Keyword: Elongation

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Authors: Yi Jie Zhang, Nai Heng Ma, Xian Feng Li, Hao Wei Wang
Abstract: A356 alloy was widely used in automobile industry due to its excellent castability and comprehensive mechanical properties. But, with increasing demands of strictly safety of components, fatigue life of A356 alloy became the key properties which were considered seriously. To evaluate the time-consuming properties, elongation, as a replaced property, was employed for its easy testing and the relationship which was proportional to the fatigue life of materials. Semi-solid processing was proved that it can improve the elongation of materials while the mechanical properties still kept at the same level as original alloy. Presently, many semi-solid techniques were developed to produce various products, in which the additional equipment was necessary to form the semi-solid microstructure. Therefore, this work is aimed to development an easily technique to obtain the semi-solid microstructure. In present study, A356 alloy with typical semi-solid microstructure was obtained by addition of RE elements during melt processing. In addition, the melting and pouring process was kept the same as the normal gravity casting of A356 alloy. After the treatment, the elongation was 19.5% for A356 alloy with RE addition, which was much higher than that of 13% for normal A356 alloy. Microstructure observation showed that the morphology of Si was changed significantly, and the shape of spheroid was dominantly appeared other than short rod shape. The improvement of elongation was attributed to the morphology change of α-Al and eutectic Si.
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Authors: Kumar Molugaram, Jaya S. Shanker, Adepu Ramesh
Abstract: Aggregate characteristics of shape, texture and grading influence on workability, finishability, bleeding, pumpability and segregation of fresh concrete and affects the strength, shrinkage, density, and durability of hardened concrete. About 80% of total volume of concrete consists of aggregate. Construction and durability problems have been reported due to poor mixture proportioning and variation on grading. Aggregate characteristics significantly affect the performance of Quality Concrete (QC) both in fresh and hardened state and have an impact on the cost effectiveness. Flaky and elongated particles lead to higher voids than cubical, rounded and well graded particles. The shape factor of aggregate plays a vital role in the design and performance of QC mix and it is mainly depends on the rock formation and type of crusher being used for crushing the aggregates. Flaky and elongated particles have larger specific surface area which results in higher demand of cement paste in cement concrete mix. These particles impede compaction or break during rolling and decrease the strength of the concrete structures. An attempt is made to study the effect of shape of aggregate on quality of the concrete used for the buildings and pavements. Initially an aggregate samples were collected from the stone crusher (two types) and prepared with different proportions of Flakiness and Elongation indices to conduct tests on properties of aggregates and compressive strength and flexural strength tests on concrete. The effect of different percentages from 0 to 50% of combined Flaky and Elongation Aggregates (CFEA) for quality concrete on the compressive and flexural strength of cement concrete is studied. The other properties of aggregate such as bulk density, impact value, water absorption have been studied for different shapes of aggregates. The cost analysis has been carried out with an optimum value of 30% CFEA in 1:3 proportions of flaky and elongated particles.
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Authors: Pei Jian Zhao, Cun Long Zhou, Wei Na Li, Qing Xue Huang, Yuan Hua Shuang
Abstract: In the tension leveling process, calculation of the strip elongation by the traditional method only considers the extension rate after the tension response, while ignoring elastic bending recovered, so the calculation of elongation is large enough to affect the process control accuracy. This paper considers not only the residual strain after elastic bend recovery, but also the affection of the residual deformation under plain cross-section assumption. The calculation of the elongation is less 4-10% than that of the traditional one. It shows that parameters of the tension leveling process set by the new method will be calculated accurately.
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Authors: Hwan Jin Sung, Tae Kwon Ha, Sang Ho Ahn, Young Won Chang
Abstract: In the present study, powder injection molding (PIM) process, in which the porosity of sintered parts can be easily controlled, has been employed to produce specimens with the various porosities from the initial stage of sintering and to the stage of nearly full density. A series of tensile tests has been conducted on these specimens at room temperature to elucidate the effect of a wide range of porosity. The material used in this study was 17-4 PH stainless steel, which is the precipitation hardenable stainless steel containing 4% of Cu and well known to show high strength and the high corrosion resistance at the same time. The 17-4 PH stainless steel powders used in this study were produced by the high-pressure water atomization method. Based on the results of tensile tests on the specimens with the various porosity, a new approach to predict the elongation of sintered materials has been carried out and a new framework combining neck growth model and ideal pore model has been established.
645
Authors: Yun Tong
Abstract: Tension and elongation of warp is the key factors among various technical parameters in warp sizing process in textile production. Analysis of composition of tension & elongation in different zone on sizing machine.By means of mechanical device and electric sensor, as well as frequency conversion speed regulator controlled by PLC, the sizing warp tension &elongation has been regulated precisely. The principles and features of various sensors and their application on modern sizing machine regarding automation have been discussed in this paper.
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Authors: M. Sangeetha, S. Prakash
Abstract: Aluminium alloy(A 356) has improved properties such as tension and elongation butit is decreased in hardness property compared to ceramics and therefore silicon carbideparticle (SiCp) is added with aluminium alloy to increase its hardness. Silicon Carbideparticle is abrasive and hence having poor interfacial bonding between ceramics andaluminium, so that the surface of the ceramics is coated with Multi Wall Carbon Nano Tubes(MWCNT). In this paper 10% of SiCp is taken for the experiment and coated with 1.5%, 2%,2.5% of MWCNT and this coated SiCp mixed with molten A 356 using stir casting method.The prepared castings were mechanically tested using Universal Testing Machine (UTM),Vickers hardness Testing Machine, Impact Testing Machine and Optical Microscope andtheir mechanical properties and morphological characteristics were studied
333
Authors: Cun Long Zhou, Zheng Yi Jiang, Guo Dong Wang, Dong Gang Xie, Yong An Zhang
Abstract: In this paper, a new method considering the combination of tension and deformation curvature which results in less deformation energy under a certain elongation is presented at the first time. The calculation results show that when the elongation is less than 1 %, the tension which is about 1/6 yield stress will consume less energy. If the tension decreases from 1/4 to 1/8 yield stress, the deformation energy of strip with yield stress of greater than 450 MPa decreases significantly. This study can help determine the processes parameters of strip tension levelling effectively.
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Authors: Kurt Wostyn, Tae Gon Kim, Paul W. Mertens, Jin Goo Park
Abstract: When a physical cleaning technology, such as megasonic and high-velocity-liquid aerosol cleaning, is considered for the removal of particles or photo resist residues, damage addition is a major concern. After detection of defects in long gate stack lines by bright field inspection (KT2800), SEM imaging shows they extend over a length in the order of 1μm (Figure 1) [1].
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Authors: Ya Zhong Zhao, Fu Sheng Pan, Jian Peng, Jun Zhou
Abstract: The properties and microstructures after different annealing processes of an as-extruded ME magnesium alloy were investigated. The results showed the better properties with the tensile strength of 205 MPa and the elongation of 19.8%, respectively, could be obtained after annealing at 623 K for 4h and air-cooled, meaning that elongation value increased 40% than that of as-extruded sheets while the strength remained almost same. The annealing hold time corresponding with the higher elongation would shorten with the increase of annealing temperature. There is legible necking on broken tensile specimen. The behavior of fracture showed obvious characteristic of ductile rupture, with many tearing edges and cavities.
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Authors: Guo Dong Shi, Jun Qiao
Abstract: Annealing treatments at 200°C, 250 °C, 300°C, and 350°C were conducted on a twin-roll casted AZ31 sheet with an initial average grain size of 10.11 mm. Microstructure and mechanical behaviors were studied by optical microscope observation and tensile mechanical test. Expermeintal results show that grain size experienced three stage evolution during 180 min annealing at each temperature: recrystallization refinement, stabilization under dynamic balance of recrystallization and grain growth, and grain growth. The minimum average grain size of 5.96 μm was achieved after 120 min annealing at 200°C. The refined grain structure causes a decrease of ultimate tensile strength and an increase of elongation, and facilitates superplastic deformation of the material.
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