Yazar "Guenduez, S." seçeneğine göre listele

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    Effect of aging temperature and martensite by volume on strain aging behaviour of dual phase steel
    (Taylor & Francis Ltd, 2008) Guenduez, S.; Demir, B.; Kacar, R.
    A study has been made of the cold deformation aging susceptibility of dual phase steel with 14 and 22% martensite by volume. It was found that yield strength (YS) and ultimate tensile strength (UTS) increased with increasing testing temperature up to 200 degrees C and then decreased at 250 degrees C which indicated that static strain aging is dominant up to 200 degrees C. This aging is associated with free dislocations in the ferrite as a result of the austenite-martensite transformation, which become preferential sites for solute atom diffusion. At higher temperature (250 degrees C) a softening effect is dominant due to tempering of martensite. It was also observed that at a given aging temperature YS, UTS and Delta Y (increase in stress due to strain aging) increased with by volume of martensite.
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    FRICTION STIR SPOT WELDABILITY OF Al-Cu-Al MATERIAL COUPLE
    (Gazi Univ, Fac Engineering Architecture, 2011) Kacar, R.; Emre, H. Ertek; Demir, H.; Guenduez, S.
    Recently joining of metallic materials has gained a big importance. The problem can arise joining of advanced and new materials especially in industry. Thus, the solid state bonding methods have become much more popular effective in joining such materials. One of them is friction stir spot welding. In this study, 5754 quality aluminum couple using interlayer copper were joined by friction stir spot welding method using 1000 and 1600 rpm pin rotation for 3 and 5 second time intervals. The mechanical and metallurgical properties of weldment determined. The finding from this study compared with result that was obtained from FSSW Al-Al couple. The mechanical properties of FSSW welded Al-Cu-Al couple found better than Al-Al weldment.
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    Strengthening of 6063 aluminium alloy by strain ageing
    (Redakcia Kovove Materialy, 2008) Guenduez, S.; Kacar, R.
    In this study, the artificial ageing behaviour of 6063 Al-alloy is investigated. A certain part of the aluminium test pieces was solution heat treated (SHT) at 520 degrees C for 2 h, water quenched, then aged at 180 degrees C for 1, 3, 5, 7, 9 and 15 h and the other part was pre-strained for 2 % in tension shortly after the solution heat treatment (SHTP), then aged at 180 degrees C for 1, 3, 5, 7, 9, 15 h in a furnace. Tensile strength, flow stress at 3 %, microhardness and electrical conductivity measurements were employed to investigate the effect of artificial ageing on the mechanical properties of Al-alloy. The variations in ageing time have improved the mechanical properties of the 6063 Al-alloy, whereas the ductility has decreased. The experimental work has revealed that different ageing times at 180 degrees C play a very important role in the precipitation hardening process of the 6063 Al-alloy.