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  • Küçük Resim Yok
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    Bio-properties of Mg-RE alloys: an applied study on cytotoxicity and genotoxicity
    (Taylor & Francis Ltd, 2024) Djebari, Kenza; Turen, Yunus; Elen, Levent; Ahlatci, Hayrettin; Bozer, Busra Moran; Cicek, Bunyamin
    This study presents a comprehensive review of magnesium alloys with rare elements. It discusses Mg-RE alloys and includes an experimental process. Thus, the data obtained by examining Mg-RE alloys provided a better interpretation of the experimental study. In this study's investigation report, Mg-RE alloys were thoroughly analyzed. In the experimental part, the cytotoxic and genotoxic results of the rare elements added to the Mg-Zn-RE master alloy are discussed. Experiments were carried out by adding Nd and Ce to this master alloy in inverse proportions. In cytotoxic data, it was observed that the viability rate in bacteria increased by up to 200%. In addition, significant genotoxic results of Mg-RE alloys were obtained, which are uncommon in the literature. As a result, a new perspective on Mg-RE alloys has been created. Cette & eacute;tude pr & eacute;sente un examen complet des alliages de magn & eacute;sium contenant des & eacute;l & eacute;ments rares. Elle discute des alliages Mg-ER et comprend un proc & eacute;d & eacute; exp & eacute;rimental. Ainsi, les donn & eacute;es obtenues en examinant les alliages Mg-ER ont fourni une meilleure interpr & eacute;tation de l'& eacute;tude exp & eacute;rimentale. Dans le rapport d'investigation de cette & eacute;tude, on a analys & eacute; & agrave; fond les alliages Mg-ER. Dans la partie exp & eacute;rimentale, on discute des r & eacute;sultats cytotoxiques et g & eacute;notoxiques des & eacute;l & eacute;ments rares ajout & eacute;s & agrave; l'alliage m & egrave;re Mg-Zn-ER. On a r & eacute;alis & eacute; des exp & eacute;riences en ajoutant du Nd et du Ce & agrave; cet alliage m & egrave;re en proportions inverses. Dans les donn & eacute;es cytotoxiques, on a observ & eacute; que le taux de viabilit & eacute; des bact & eacute;ries a augment & eacute; jusqu'& agrave; 200%. De plus, on a obtenu des r & eacute;sultats g & eacute;notoxiques significatifs des alliages Mg-ER, qui sont peu communs dans la litt & eacute;rature. Par cons & eacute;quent, on a cr & eacute;& eacute; une nouvelle perspective sur les alliages Mg-ER.
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    Effect of different element addition and application of extrusion on the biodegradation properties of ZW21 series mg alloy
    (Karabük Üniversitesi, Lisansüstü Eğitim Enstitüsü, 2024) Djebari, Kenza; Türen, Yunus
    In this study, microstructure, mechanical, dry and corrosive wear properties, H2 evolution of the as-cast and hot-extruded ZW21 alloys were investigated. The reference ZW21 alloy was obtained by adding 2 (wt.%) Zinc (Zn) and 1 (wt.%) Yttrium (Y) elements to pure Mg. Afterwards, constant amounts of Zirconium (Zr), Lanthanum (La), Gadolinium (Gd), Silver (Ag), and Calcium (Ca) elements (0.5 (wt.%)) were added into other three ZW21 alloys, then different amounts of Neodyum (Nd) and Cerium (Ce) (1 and 2 (wt.%)) were added conversely to two of the last three alloys in order to obtain four different alloys. A total of four different alloys were produced as reference ZW21, ZW21+(0.5%) ZrLaGdAgCa, and ZW21+(1% and 2%)NdCe+(0.5%)ZrLaGdAgCa and ZW21+(2% and 1%)NdCe+(0.5%)ZrLaGdAgCa. The melting processes of the investigated alloys were carried out in an atmosphere-controlled induction furnace by using shielding gas as Argon, while the casting processes were carried out under shielding gas CO2+1SF6. The hot extrusion process applied after the casting was carried out with a hydraulic press at an extrusion rate of 2.24:1, at a speed of 0.3 mm/s, at 400°C. Before the hot extrusion process, homogenization annealing was applied to the samples at 430°C for 48 hours. Microstructure, hardness, dry and corrosive wear tests were carried out on the as-cast and extruded samples. Tensile tests were carried out on the extruded samples only. H2 evolution for 72 hours and Corrosion tests applied to the alloys were performed in Hank's solution environment and at ~36.5°C. Corrosive wear tests were carried out in Hank's solution environment, at room temperature, using the reciprocating wear method, under a load of 20 N and a sliding distance of 400 meters. cytotoxicity test performed on ZW21, ZW21+(1% and 2%)NdCe+(0.5%)ZrLaGdAgCa and ZW21+(2% and 1%)NdCe+(0.5%)ZrLaGdAgCa as-cast samples. XRD analysis identified the presence of α-Mg, I-phase (Mg₃Zn₆Y₂), W-phase (Mg₃Zn₃Y₂), and LPSO (Mg₁₂ZnY), with the amount and distribution of these phases strongly influencing the mechanical and corrosion properties. Notably, the unique Mg41Nd5 phase in ZW21+(1% and 2%) NdCe+(0.5%)ZrLaGdAgCa contributed to its improved corrosion resistance compared to ZW21+0.5(Zr, La, Gd, Ag, Ca) and ZW21+(2% and 1%)NdCe+(0.5%)ZrLaGdAgCa, which contained phases such as Ca2Mg6Zn3 and Mg-Ag, known to accelerate corrosion. The alloys exhibited refined grain structures and enhanced hardness following extrusion, with ZW21+(2% and 1%)NdCe+(0.5%)ZrLaGdAgCa exhibiting the highest hardness (68.8 HV) and finest grain size (46 μm). ZW21+0.5(Zr, La, Gd, Ag, Ca) demonstrated the second-best mechanical properties. In terms of wear resistance, all alloys exhibited improved wear resistance after extrusion, with ZW21+(1% and 2%)NdCe+(0.5%)ZrLaGdAgCa performing best in as-cast conditions but showing increased wear in the extruded state. Corrosion tests demonstrated that ZW21 had the best corrosion resistance in both as-cast and extruded states, largely due to the absence of corrosion-accelerating phases like LPSO. Extrusion improved the corrosion resistance of ZW21+0.5% (Zr, La, Gd, Ag, Ca)+1%Nd2%Ce and ZW21+0.5% (Zr, La, Gd, Ag, Ca)+2%Nd1%Ce, although their performance remained lower than ZW21. The hydrogen evolution rate for ZW21+0.5% (Zr, La, Gd, Ag, Ca)+1%Nd2%Ce was the highest, indicating greater corrosion, while ZW21 and ZW21+0.5% (Zr, La, Gd, Ag, Ca)+2%Nd1%Ce had the lowest H₂ evolution rates, approaching acceptable levels for biodegradable implants. The study examines the biocompatibility of ZW21 and its modified alloys ZW21+0.5% (Zr, La, Gd, Ag, Ca)+1%Nd2%Ce and ZW21+0.5% (Zr, La, Gd, Ag, Ca)+ 2%Nd1%Ce demonstrating successful high cell viability rates, confirming their potential as biocompatible materials for orthopedic implants.