Browsing Faculty of Engineering by Author "(ORCID 0000-0001-5692-4809 & YÖK ID 163236) Yapıcı, Güven"
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Application of a novel friction stir spot welding process on dissimilar aluminum joints
Bajilane, Isam Jabbar Ibrahim; Yapıcı, Güney Güven (Elsevier, 2018-10)Intermediate layer friction stir spot welding (IL-FSSW) is introduced in this study as a novel spot welding technique to eliminate the keyhole associated with the conventional friction stir spot welding (FSSW). This process ... -
Cyclic deformation response of ultra-fine grained titanium at elevated temperatures
Sajadifar, Seyed Vahid; Yapıcı, Güney Güven; Demler, E.; Krooss, P.; Wegener, T.; Maier, H. J.; Niendorf, T. (Elsevier, 2019-05)This study focuses on the high-temperature cyclic deformation response (CDR) of ultra-fine grained (UFG) titanium of commercial purity (grade 4) processed via equal channel angular extrusion as a severe plastic deformation ... -
Development of an antagonistically actuated smart joint
Vahidyeganeh, Ali; Simsek, Görkem Muttalip; Jabeen, Saher; Bebek, Özkan; Yapıcı, Güney Güven (Trans Tech Publications, 2017)Shape memory alloys with their phase transformation properties; have been broadly implemented in smart structures. In this study, a functional design is presented where two wires actuate antagonistically to achieve motion ... -
Discrete-time integral sliding mode control of a smart joint for minimally invasive surgeries
Jabeen, Saher; Yeganeh, Ali Vahid; Simsek, Görkem Muttalip; Yapıcı, Güney Güven; Abidi, K.; Bebek, Özkan (IEEE, 2016)In this work, a shape memory alloy(SMA) actuator based joint (smart joint) is controlled using a discrete-time integral sliding mode (DISM) control to guide the motion of an active catheter. Controller is designed on the ... -
Effect of commercial purity levels on the mechanical properties of ultrafine-grained titanium
Purcek, G.; Yapıcı, Güney Güven; Karaman, I.; Maier, H. J. (Elsevier, 2011-03-15)Two grades of commercial purity (CP) titanium (grades 2 and 4) were processed using equal-channel angular extrusion (ECAE) at 300 ◦C and 450 ◦C, respectively. The processing temperatures were the minimum temperatures at ... -
Effect of grain size on the very high cycle fatigue behavior and notch sensitivity of titanium
Sajadifar, Seyed Vahid; Wegener, T.; Yapıcı, Güney Güven; Niendorf, T. (Elsevier, 2019-12)The very high-cycle fatigue performances of coarse-grained and ultrafine-grained titanium samples with different geometries at ambient temperature and various stress amplitudes were investigated. Severe plastic deformation ... -
Effect of heat treatment on the corrosion-fatigue of NiTi shape memory alloy
Şimşek, Görkem Muttalip; Sayınbaş, Yiğit Kaan; Uysal, Miray; Yapıcı, Güney Güven (American Institute of Physics Inc., 2019)Nickel Titanium (NiTi) shape memory alloys have been considered convenient implant material due to their distinguished properties including superelasticity (SE), shape memory effect (SME) and biocompatibility. Among these ... -
Effect of processing parameters on the strength of keyhole free friction stir spot aluminum welds
Bajilane, Isam Jabbar Ibrahim; Yapıcı, Güney Güven (American Institute of Physics Inc., 2019)Intermediate layer friction stir spot welding (IL-FSSW) is a new solid-state welding method appropriate for making spot joints, particularly in light-weight materials, especially notable on account of the weight saving ... -
Effect of purity levels on the high-temperature deformation characteristics of severely deformed titanium
Sajadifar, Seyed Vahid; Yapıcı, Güney Güven (Springer International Publishing, 2017)In the present investigation, high-temperature compression tests were conducted at strain rates of 0.001 to 0.1 s−1 and at temperatures of 873 K to 1173 K (600 °C to 900 °C) in order to study the hot deformation characteristics ... -
Effect of severe plastic deformation on the damping behavior of titanium
Sajadifar, Seyed Vahid; Atli, C.; Yapıcı, Güney Güven (Elsevier, 2019-06-01)In this work, influence of severe plastic deformation on the damping properties of commercial purity titanium is explored. Deformation induced grain refinement improved the strength at room temperature while this effect ... -
Elevated temperature mechanical behavior of severely deformed titanium
Sajadifar, Seyed Vahid; Yapıcı, Güney Güven (Springer Nature, 2014-05)In this investigation, compression tests were performed at a strain rate of 0.001-0.1 s(-1) in the range of 600-900 degrees C to study the high temperature deformation behavior and flow stress model of commercial purity ... -
Evaluation of NaOH pre-treatment on the corrosion behavior and surface characteristics of hydroxyapatite coated NiTi alloy
Şimşek, Görkem Muttalip; Ipekoglu, M.; Yapıcı, Güney Güven (Springer Nature, 2020-08-02)Successful short-term implementation of nickel-titanium (NiTi) alloys as implants has been a motivation for the development of long-term applications. However, rendering these as safe implant materials is challenging. The ... -
Fatigue behavior of friction stir welded joints of pure copper with ultra-fine grains
Salahi, Salar; Yapıcı, Güney Güven (Elsevier, 2015)In order to determine the long term durability of friction stir welded joints with ultra-fine grained microstructure, investigation of the mechanical response with specific emphasis on fatigue behaviour is critical. In ... -
Fatigue characteristics of continuous welded rails and the effect of residual stress on fatigue-ratchetting interaction
Mansouri, Deniz; Şendur, Polat; Yapıcı, Güney Güven (Taylor & Francis, 2020-03-16)The importance of ratchetting-fatigue interaction is garnering interest due to complex failure mechanism of rail welds under cyclic loading. The objective of this paper is to investigate the fatigue characteristics of ... -
Formation of nano-sized compounds during friction stir welding of Cu–Zn alloys: effect of tool composition
Heidarzadeh, A.; Radı, Amın; Yapıcı, Güney Güven (Elsevier, 2020-12)For the first time, the origin of tool composition effect on microstructure and mechanical properties of the friction stir welded joints has been disclosed. For this aim, nanoindentation, orientation image microscopy, and ... -
Fracture behavior of ultrafine-grained titanium under tension at elevated temperatures
Sajadifar, Seyed Vahid; Maier, H. J.; Yapıcı, Güney Güven (ASME, 2020-10-01)This investigation focused on the deformation response and microstructural changes of severely deformed titanium during post-severe plastic deformation tension, at temperatures of 300–600 °C and at strain rates of 0.001–0.1 ... -
High temperature characteristics of Al2024/SiC metal matrix composite fabricated by friction stir processing
Ghobadlou, Ali Hosseinzadeh; Yapıcı, Güney Güven (Elsevier, 2018-07-25)In the present study, friction stir processing (FSP) is used for the synthesis of an aluminum metal matrix composite (MMC) reinforced by SiC particles. MMC specimens with reinforced microstructures exhibited significant ... -
High temperature deformation behavior of 4340 steel: activation energy calculation and modeling of flow
Sajadifar, Seyed Vahid; Yapıcı, Güney Güven; Ketabchi, M.; Bemanizadeh, B. (Elsevier, 2013-12)The 4340 steel is extensively utilized in several industries including automotive and aerospace for manufacturing a large number of structural components. Due to the importance of thermo-mechanical processing in the ... -
High temperature flow response modeling of ultra-fine grained titanium
Sajadifar, Seyed Vahid; Yapıcı, Güney Güven (MDPI AG, 2015)This work presents the mechanical behavior modeling of commercial purity titanium subjected to severe plastic deformation (SPD) during post-SPD compression, at temperatures of 600-900 °C and at strain rates of 0.001-0.1 ... -
Hot deformation behavior of ultra-fine grained pure Ti
Sajadifar, Seyed Vahid; Yapıcı, Güney Güven (Trans Tech Publications, 2013-11)In the present study, compression tests were performed at a strain rate of 0.001 to 0.1 s(-1) and in the range of 600 degrees C to 900 degrees C to investigate the high temperature deformation behavior and flow stress model ...
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