Protein is one of the non elastomeric constituents in natural rubber that has important effects on its properties. In this work, a comparative study on the effect of the natural rubber protein content that was obtained by two Kjeldahl and Fourier transform infrared spec More
Protein is one of the non elastomeric constituents in natural rubber that has important effects on its properties. In this work, a comparative study on the effect of the natural rubber protein content that was obtained by two Kjeldahl and Fourier transform infrared spectroscopy methods considered on the tensile properties of rubber compounds and second order correlation models were obtained. These models were used to predict the tensile properties of natural rubber based compounds. The results showed that the Fourier transform infrared spectroscopy method is more successful for prediction of the properties. Tensile strength and modulus 100% were predicted by less than 10% error, elongation at break and modulus 300% were also estimated by less than 25% error. This new approach makes it possible to predict the tensile properties of rubber compounds before preparing,, by consuming a small amount of natural rubber and using a fast and non destructive technique.
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In this study, the effects of cold rolling and intermediate and final annealing on the microstructure and tensile properties of Hastelloy X alloy was investigated. Three-stage cold rolling followed by intermediate annealing at 1175 ºC for 0.5 hr were performed on 1 More
In this study, the effects of cold rolling and intermediate and final annealing on the microstructure and tensile properties of Hastelloy X alloy was investigated. Three-stage cold rolling followed by intermediate annealing at 1175 ºC for 0.5 hr were performed on 10 mm thick strip at hot rolled and solution annealed condition to obtain the final thickness of 1.25 mm. The specimens prepared for tensile test within temperature range 660- 860 ºC, annealed at 1100-1200ºC for 1 hr. Microstructural investigation of the specimen’s solution annealed at temperature 1175 ºC indicated the matrix is austenite and dispersed particles are M6C carbides which are molybdenum rich precipitates. Hot tensile test results for specimens annealed at 1100, 1150 and 1200 ºC indicated a minimum ductility, at 760, 760 and 860 ºC, respectively. Tensile tests showed that the yield strength of the alloy had a weak temperature-dependence for temperature range 660- 860ºC, due to precipitation of molybdenum rich M6C carbides.
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In this study, the effect of Cu addition (0.5, 1.0 and 1.5 wt%) and T6 heat treatment on the tensile properties and quality index of A356 alloy containing different amount of iron (0.5-1.5 wt%) was investigated. According to the results in as-cast condition, the additio More
In this study, the effect of Cu addition (0.5, 1.0 and 1.5 wt%) and T6 heat treatment on the tensile properties and quality index of A356 alloy containing different amount of iron (0.5-1.5 wt%) was investigated. According to the results in as-cast condition, the addition of copper to the iron bearing alloys increased the tensile strength by about 25% while substantially decreased the percent elongation (by almost 80%). After heat treatment, however, the tensile strength and the quality index of the alloy containing 1 wt% copper and 1.5 wt% iron were found to be increased by about 100 and 35% as compared to the base alloy, respectively. The improvement in the quality index was attributed to the precipitation hardening effect of Al2Cu and Mg2Si precipitates as well as thermal modification of eutectic silicon and iron-rich platelets, which increase the tensile strength, and ductility of the alloy.
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In present research, the effect of tool transverse speed on the microstructure and mechanical properties of friction stir welded DP700 dual-phase steel has been studied. Welding process conducted at a rotational speed of 800 rpm and tool transverse speeds of 50 and 100 More
In present research, the effect of tool transverse speed on the microstructure and mechanical properties of friction stir welded DP700 dual-phase steel has been studied. Welding process conducted at a rotational speed of 800 rpm and tool transverse speeds of 50 and 100 mm/min. Optical and scanning electron microscopy were used for microstructural examinations, and mechanical properties were evaluated using microhardness measurements and tensile test. Microstructural investigation revealed that the stir zone consists of bainite, acicular ferrite and polygonal ferrite. It was also revealed that the heat-affected zone (HAZ), based on the peak temperature (Tp), can be subdivided into three different regions: 1) inner HAZ, where Tp is higher than Ac3, 2) Middle HAZ, where Tp lies between Ac1 and Ac3, 3) Outer HAZ in which Tp is lower than Ac1. It was also found that the martensite phase tempers in OHAZ and the degree of tempering decreases with the increment of tool transverse speed. This results confirmed by microhardness measurements where the hardness reduction of the softened zone decreased from 28 to 20HV with an increment of tool transverse speed. The highest hardness of the joints corresponded to the stir zone, and its value increased from 345 to 375HV with rising tool transverse speed. Tensile test results showed that the ultimate strength of the joints was lower than the base metal (723MPa) and it increases from 662 to 671MPa with rising tool transverse speed. It was also revealed that increasing transverse speed improves the total elongation by 2.6%.
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در این پژوهش تاثیر کسر حجمی فاز تقویت کننده برخواص کششی کامپوزیت Al6061/SiC با اعمال اکستروژن گرم مورد بررسی قرار می­گیرد.کامپوزیت های آلومینیم – سیلیسیم به دلیل خواص سایشی و مکانیکی بالا مورد توجه هستند. برای انجام این تحقیق کامپوزیت Al6061/SiC با درصده More
در این پژوهش تاثیر کسر حجمی فاز تقویت کننده برخواص کششی کامپوزیت Al6061/SiC با اعمال اکستروژن گرم مورد بررسی قرار می­گیرد.کامپوزیت های آلومینیم – سیلیسیم به دلیل خواص سایشی و مکانیکی بالا مورد توجه هستند. برای انجام این تحقیق کامپوزیت Al6061/SiC با درصدهای مختلف 5، 10 ، 15 و 20 درصد کاربید سیلیسیم به روش ریخته­گری هم­زدنی تولیدشد و بر روی نمونه‎های کامپوزیتی حاوی کسرهای حجمی ذکرشده، عملیات اکستروژن گرم انجام شد. سپس خواص کششی محصول مورد بررسی قرار گرفت. در ادامه بررسی­های ریزساختاری با استفاده از میکروسکوپ نوری و الکترونی انجام شد. نتایج بدست آمده نشان می دهد که افزایش میزان کاربید سیلیسیم تا 5 درصد وزنی باعث افزایش استحکام کششی کامپوزیت فوق گردید. همچنین اعمال فرآیند اکستروژن باعث کاهش میزان تخلخل نسبت به حالت ریختگی و در نتیجه بهبود خواص کششی شد.
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