Browsing by Author "Canadinc, Demircan"

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Corrosion behavior of novel Titanium-based high entropy alloys designed for medical implants
(ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND, 2020) Yagci, Mustafa Baris; Bal, Bekir Cihad; Canadinc, Demircan; Gurel, S.; 0000-0001-9961-7702; 0000-0002-3176-2388; AGÜ, Mühendislik Fakültesi, Makine Mühendisliği Bölümü
This paper reports on the corrosion behavior of three TiTaHf-based high entropy alloys (HEAs) in simulated body fluid (SBF) and artificial saliva (AS) in order to assess their potential utility as implant materials. Specifically, TiTaHfNb, TiTaHfNbZr and TiTaHfMoZr HEAs were subjected to static immersion experiments in SBF and AS, and both the surfaces of the samples and the immersion fluids were thoroughly examined with the state of the art techniques. The experimental results presented herein revealed that the presence of Zr and Nb in the TiTaHf-based samples enhanced corrosion performance with reduced ion release and better surface properties, while Mo addition resulted in an inhomogeneous microstructure, leading to dendrite structures and significant amount of ion release upon immersion in both media. Furthermore, a protective passive layer formation or crystallization was present on all HEA surfaces, implying that corrosion resistance can be sustained in long-term applications. Overall, the set of findings presented herein constitute an early indication of the potential of the TiTaHf-based HEAs to be utilized as implant materials.
High-concentration carbon assists plasticity-driven hydrogen embrittlement in a Fe-high Mn steel with a relatively high stacking fault energy
(ELSEVIER SCIENCE SA, PO BOX 564, 1001 LAUSANNE, SWITZERLAND, 2018) Tugluca, Ibrahim Burkay; Koyama, Motomichi; Bal, Burak; Canadinc, Demircan; Akiyama, Eiji; Tsuzaki, Kaneaki; 0000-0001-6916-3703; 0000-0002-5006-9976; 0000-0002-7389-9155; 0000-0001-9961-7702; AGÜ, Mühendislik Fakültesi, Makine Mühendisliği Bölümü
We investigated the effects of electrochemical hydrogen charging on the mechanical properties of a Fe-33Mn-1.1C austenitic steel with high carbon concentration and relatively high stacking fault energy. Hydrogen pre charging increased the yield strength and degraded the elongation and work-hardening capability. The increase in yield strength is a result of the solution hardening of hydrogen. A reduction in the cross-sectional area by subcrack formation is the primary factor causing reduction in work-hardening ability. Fracture modes were detected to be both intergranular and transgranular regionally. Neither intergranular nor transgranular cracking modes are related to deformation twinning or simple decohesion in contrast to conventional Fe-Mn-C twinning induced plasticity steels. The hydrogen-assisted crack initiation and subsequent propagation are attributed to plasticity-dominated mechanisms associated with strain localization. The occurrence of dynamic strain aging by the high carbon content and ease of cross slip owing to the high stacking fault energy can cause strain/damage localization, which assists hydrogen embrittlement associated with the hydrogen-enhanced localized plasticity mechanism.