• Transactions of Materials Processing
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• v.31 no.2
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• pp.64-72
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• 2022

Since aluminum alloys experience both tensile and compression deformation modes during forming process, it is important to understand the role of deformation mode on the hot formability of metallic alloys. In the present work, the hot formability of Al7050 alloy was investigated by conducting both tensile and Gleeble tests at various temperatures and strain rates. Processing maps representing low efficiency regions were observed at low temperature and high strain rate in both tensile and compressive deformation modes while the maximum efficiency regions depended on different deformation modes. Moreover, samples tested at stable processing conditions presented a smaller pore fraction than those at instable conditions that resulted in crack initiation during plastic deformation. This result shows that different deformation modes during plastic forming can affect formability changes of metallic alloys. Understanding of tension-compression behaviors will help us solve this problem.

• Fashion & Textile Research Journal
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• v.1 no.3
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• pp.288-295
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• 1999

This study was conducted to examine the fatigue phenomenon of mechanical properties in tencel fabrics by repeated washing & shear and tensile deformation. The obtained results are as follows. After performing repeated shear tensile deformation, RT of tencel showed higher increase rate than that of cotton and rayon, whereas its WT and EM was a smaller decrease rate than that of them. This means that tencel's resistance to tensile deformation was the greatest. In the repeated washing and shear tensile deformation, tencel's 2HB, 2HG and 2HG5 showed a remarkable increase rate. In terms of deformation frequency, the greatest change rate appeared at the time of 1000 cycles of repeated shear tensile deformation and 15 times of repeated washing. In the hand value and THV, KOSHI showed a higher increase rate for tencel than for cotton and rayon in both repeated washing and shear tensile deformation, and NUMERI showed a higher increase rate. In the THV the change rate of rayon and cotton could be rarely seen but for tencel, it decreased. tencel's change rate of thermal insulation value by materials was 1.08%, and it increased as the washing frequency increased, compared to the grey fabrics, whereas the change rates of cotton and rayon were 0.74% and 0.22%, respectively. The qmax decreased in the order of cotton>tencel>rayon as the washing frequency increased.

• Transactions of Materials Processing
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• v.18 no.6
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• pp.500-507
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• 2009

Tensile deformation behavior with different strain rate was investigated. $Zr_{56.2}Ti_{13.8}Nb_{5.0}Cu_{6.9}Ni_{5.6}Be_{12.5}$(bulk metallic glass alloy possessed crystal phase which was called $\beta$-phase of dendrite shape, mean size of $20{\sim}30{\mu}m$ and occupied 25% of the total volume) was used in this study. Maximum tensile strength was obtained as 1.74GPa at strain rate $10^2s^{-1}$ and minimum strength was found to be 1.6GPa at $10^{-1}s^{-1}$. And then, maximum plastic deformation occurred at the strain rate of $5{\times}10^{-2}s^{-1}$ and represented 1.75%, though minimum plastic deformation showed 0%. In the specific range of strain rate, relatively higher plastic deformation and lower ultimate tensile strength were found with lots of shear bands. The fractographical observation after tensile test indicated that vein like pattern on the fracture surface was well developed especially in the above range of strain rate.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.353-354
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• 2009

Tensile deformation behavior with different strain rate was investigated. $Zr_{56.2}Ti_{13.8}Nb_{5.0}Cu_{6.9}Ni_{5.6}Be_{12.5}$ (bulk metallic glass alloy possessed crystal phase which was called $\beta$-phase of dendrite shape, mean size of $20{\sim}30{\mu}m$ and occupied 25% of the total volume) was used in this study. Maximum tensile strength was obtained as 1.74Gpa at strain rate of $10^2/s$ and minimum strength was found to be 1.6GPa at $10^{-1}/s$. And then, maximum plastic deformation occurred at the strain rate of $5{\times}10^{-2}/s$ and represented 1.75%, though minimum plastic deformation showed 0%. In the specific range of strain rate, relatively higher plastic deformation and lower ultimate tensile strength were found with lots of shear bands. The fractographical observation after tensile test indicated that vein like pattern on the fracture surface was well developed especially in the above range of strain rate.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.6
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• pp.609-620
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• 2002

It is well known that during tensile testing, a part of the mechanical work done on the specimen is transformed into heat energy. However, the ultimate temperature rise and the rate of temperature rise is related to the nature of the material, conditions of the test and also to the deformation behaviour of the material during loading. The recent advances in infrared sensors and image/data processing techniques enable observation and quantitative analysis of the heat energy dissipated during such tensile tests. In this study, infrared imaging technique has been used to characterise the tensile deformation in AISI type 316 nuclear grade stainless steel. Apart from identifying the different stages during tensile deformation, the technique provided an accurate full-field temperature image by which the point and time of strain localization could be identified. The technique makes it possible to visualise the region of deformation and failure and also predict the exact region of fracture in advance. The effect of thermal gradients on plastic flow in the case of interrupted straining revealed that the interruption of strain and restraining at a lower strain rate not only delays the growth of the temperature gradient, but the temperature rise per unit strain decreases. The technique is a potential NDE tool that can be used for on-line detection of thermal gradients developed during extrusion and metal forming process which can be used for ensuring uniform distribution of plastic strain.

• Nuclear Engineering and Technology
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• v.44 no.8
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• pp.953-960
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• 2012

This paper reports the irradiation effect on the deformation behavior and tensile fracture properties of A533B RPV steel. An inverse identification technique using iterative finite element (FE) simulation was used to determine those properties from tensile data for the A533B RPV steel irradiated at 65 to $100^{\circ}C$ and deformed at room temperature. FE simulation revealed that the plastic instability at yield followed by softening for higher doses was related to the occurrence of localized necking immediately after yielding. The strain-hardening rate in the equivalent true stress-true strain relationship was still positive during the necking deformation. The tensile fracture stress was less dependent on the irradiation dose, whereas the tensile fracture strain and fracture energy decreased with increasing dose level up to 0.1 dpa and then became saturated. However, the tensile fracture strain and fracture energy still remained high after high-dose irradiation, which is associated with a large amount of ductility during the necking deformation for irradiated A533B RPV steel.

• Transactions of Materials Processing
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• v.7 no.1
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• pp.23-35
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• 1998

In order to analyze the tensile deformation characteristics of laser welded tailored blanks. laser welded blanks of different thikness and strength combinations were prepared and tensile tests were done. The tensile elongation along the direction perpendicular to weld line of laser welded blanks was reduced as increasing the deformation restraining force (strength X thicknes) ratio between two welded sheets and fracture occurred at weaker side of base sheets if void ration of welded sheets and fracture occurred at weaker side of base sheets if void ratio of weld section was less than 45% The tensile elongation along weld line reached above 90% of the elongation of base material if welding was done perfectly. Total elongation along the direction perpendicular to weld line was able to be predicted by force equilibrium and power law behavior of base sheets and it was related with the deformation of stronger sheet and formability of weaker side.

• Korean Journal of Materials Research
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• v.26 no.6
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• pp.325-331
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• 2016

This paper presents a study of the tensile properties of austenitic high-manganese steel specimens with different grain sizes. Although the stacking fault energy, calculated using a modified thermodynamic model, slightly decreased with increasing grain size, it was found to vary in a range of $23.4mJ/m^2$ to $27.1mJ/m^2$. Room-temperature tensile test results indicated that the yield and tensile strengths increased; the ductility also improved as the grain size decreased. The increase in the yield and tensile strengths was primarily attributed to the occurrence of mechanical twinning, as well as to the grain refinement effect. On the other hand, the improvement of the ductility is because the formation of deformation-induced martensite is suppressed in the high-manganese steel specimen with small grain size during tensile testing. The deformation-induced martensite transformation resulting from the increased grain size can be explained by the decrease in stacking fault energy or in shear stress required to generate deformation-induced martensite transformation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4A
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• pp.303-309
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• 2011

Laminated rubber bearing is the most commonly used device for seismic base isolation of bridge structures. It is important to know performance and behavior characteristics of the laminated rubber bearings. The main evaluation factors of the rubber bearing are classified as compressive, shear and tensile behavior characteristics. The reference data of compressive and shear characteristics are rich, but the reference data of tensile characteristics is scarce. In this study, tensile test results of the rubber bearing with variation of shape factor and shear deformation are investigated for mechanical property. When tensile deformation in normal condition is increasing, tensile cycle behavior curve becomes non-linear and tensile breaking point is 300%. On the other hand, tensile breaking point is shear deformation condition is about 40%. Furthermore, when shape factor is lower, tensile breaking point is decrease. This results mean that tensile breaking point is decreased in triaxial tensile deformation because of cracks caused by internal void of the rubber bearings. This experimental data can be used as the reference data of tensile characteristics for designing seismic isolation of structures.

• Journal of the Korean Society for Heat Treatment
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• v.3 no.2
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• pp.20-31
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• 1990

This investigation has been carried out to make clear the effect of deformation temperature, strain rate and grain size on the tensile properties of 304L stainless steel. Tensile properties of the metastable austenitic 304L steel remarkably influenced by deformation temperature. Tensile strength increased with decreasing deformation temperature and the elongation showed maximum value near $40^{\circ}C$. In order to obtain the high elongation, a large amount of deformation is available in austenite before martensitic transformation and the martensite has to be induced gradually. Tensile strength and elongation increased with decreasing grain size. The temperature representing the maximum elongation shifted to low temperature and the peak width of elongation became broaden with decreasing austenite grain size. The volume fraction of strain induced martensite decreased with decreasing austenite grain size. As the strain rate increase, the temperature representing the maximum elongation value shifted to high temperature and volume fraction of strain induced martensite decreased.