In this study, the effects of adding Ni in different ratios to Fe-matrix material containing C-Nb-V produced by powder metallurgy on microstructure, tensile strength, hardness and corrosion behaviors were investigated. Fe-C and Fe-C-Nb-V powders containing 5%, 10%, 13%, 15%, 20%, 30% and 40% nickel were pressed at 700 MPa and then sintered in an Ar atmosphere at 1400 °C. Microstructures of the samples were characterized with optical microscope, scanning electron microscope (SEM) and XRD. Corrosion behaviors were investigated by obtaining Tafel curves in an aqueous solution containing 3.5% NaCl. Mechanical properties were determined by hardness and tensile testing. While Fe-C alloy and Fe-C-Nb-V microalloyed steel without Ni typically have a ferrite-pearlite microstructure, the austenite phase has been observed in the microstructures of the alloys with 10% nickel and further. Yield and tensile strength increased with nickel content and reached the highest strength values with 13% Ni content. The addition of more nickel led to decrease the strength. Analysis of Tafel curves showed that corrosion resistance of alloys increased with increasing nickel concentration.

à Ìåðñèíñêèé óíèâåðñèòåò, ôàêóëüòåò ìàøèíîñòðîåíèÿ, ×èôòëèê, Ìåðñèí, Òóðöèÿ á Êàôåäðà ìåòàëëóðãèè è ìàòåðèàëîâåäåíèÿ, ôàêóëüòåò ìàøèíîñòðîåíèÿ, Óíèâåðñèòåò Êûðûêêàëå, Êûðûêêàëå, Òóðöèÿ â Êàôåäðà ìåòàëëóðãèè è ìàòåðèàëîâåäåíèÿ, ôàêóëüòåò ìàøèíîñòðîåíèÿ, Óíèâåðñèòåò Êàðàáóêà, Êàðàáóê, Òóðöèÿ ã Ôàêóëüòåò ïðîôåññèîíàëüíî-òåõíè÷åñêîãî îáðàçîâàíèÿ, Óíèâåðñèòåò Êàðàáóêà, Êàðàáóê, Òóðöèÿ Èññëåäîâàíî âëèÿíèå ïðîöåññà ñòàðåíèÿ íà øåðîõîâàòîñòü ïîâåðõíîñòè è ìåõàíè÷åñêèå ñâîéñòâà àëþìèíèåâûõ ñïëàâîâ AA6061 è AA7075. Ìåõàíè÷åñêèå ñâîéñòâà èññëåäîâàëè ïðè èñïûòàíèÿõ íà ìèêðîòâåðäîñòü è ðàñòÿaeåíèå. Ïîâåðõíîñòü îáðàçöîâ èññëåäîâàëè ñ ïîìîùüþ ðåíòãåíîñòðóêòóðíîãî àíàëèçà. Ïîñëå èñïûòàíèÿ íà ðàñòÿaeåíèå ïîâåðõíîñòü ðàçðóøåíèÿ èññëåäîâàëè ìåòîäîì ðàñòðîâîé ýëåêòðîííîé ìèêðîñêîïèè. Âëèÿíèå ïðîöåññà ñòàðåíèÿ íà øåðîõîâàòîñòü ïîâåðõíîñòè èçó÷àëè ñ ïîìîùüþ àòîìíî-ñèëîâîãî ìèêðîñêîïà. Ïîêàçàíî, ÷òî ñ ðîñòîì øåðîõîâàòîñòè ïîâåðõíîñòè óâåëè÷èâàåòñÿ êîëè÷åñòâî âûäåëèâøèõñÿ ôàç.Êëþ÷åâûå ñëîâà: àëþìèíèåâûå ñïëàâû, àòîìíî-ñèëîâîé ìèêðîñêîï, ìåõàíè÷åñêèå ñâîéñòâà, ðàñòðîâàÿ ýëåêòðîííàÿ ìèêðîñêîïèÿ. Introduction.Aluminum alloys offering high strength-to-weight ratio, good formidability and high corrosion resistance are extensively used in various fields such as the aerospace and automobile industries [1][2][3][4][5][6][7][8]. Magnesium alloys, the lightest of the structural metals with a two-thirds density of aluminum alloys, have been extensively explored for practical industrial applications during the past decade [9][10][11]. The high strength-to-weight ratio makes utilization of 6xxx series Al alloys favorable for a wide variety of applications [10][11][12][13][14]. Various structural applications in automobile and aerospace

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Bu çalışmada, östenitik paslanmaz çelik (AISI 304) ve düşük karbonlu çelik (S235JR) malzemenin gaz metal ark kaynak yöntemi kullanılarak farklı akım-voltaj (kaynak enerjisi) değerleri ve tel besleme hızlarında kaynak edilebilirliği araştırılmıştır. Kaynaklı numunelere çekme testi ve sertlik deneyleri yapılarak birleştirilen malzemelerin mekanik özellikleri incelenmiş, sonuçlar Taguchi ve varyans analizi (ANOVA) metodu kullanılarak değerlendirilmiştir. Ayrıca kaynak bölgesinin mikroyapısı incelenerek, ısı tesiri altındaki bölgenin (ITAB) sertlik davranışı açıklanmaya çalışılmıştır. Çekme deneyi sonuçlarına göre deformasyon, kaynak bölgesi dışında, düşük karbonlu çelik bölgesinde meydana gelmiştir. Sertlik değerlerinin analizinde enerji girdisi artışının sertliği azalttığı, tel besleme hızındaki artışın ise sertliği artırdığı belirlenmiştir. Mikroyapı çalışmaları sonucunda, kaynak bölgesinde tane büyümesinin meydana geldiği tespit edilmiştir. ANOVA sonuçlarına göre kaynak bölgesi enerji miktarı ve tel besleme hızı parametreleri kaynak bölgesinin sertlik davranışını %70 oranında açıklayabilmektedir.

This study aims to investigate the effect of zirconium carbide (ZrC) nanoparticles on mechanical performances of pure aluminum. Composites Al-0.5ZrC, Al-1ZrC, Al-2ZrC were fabricated by powder metallurgy. Hardness test was performed for all specimens. Compression test was conducted at room temperature. Results clearly show that homogenously distribution of nanoparticles was achieved up to 1 wt% reinforcement addition according to the scanning electron microscope results. The hardness of pure aluminum was increased significantly. Compression strength was also improved considerably with the addition of nano-reinforcements. Al-1ZrC composite showed best performance among the samples.