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    Effect of applied load on adhesive wear and corrosive wear behaviours of two aluminium bronze (Cu-Al-Fe) alloys
    (Sage Publications Ltd, 2025) Metin, Meric; Unal, Mehmet; Goren, Halil Ahmet
    In this study, the microstructure, adhesive (dry) wear and corrosive wear properties of cast C95200 and C95300 aluminium bronze alloys were investigated. The most important difference for these two alloys is that C95200 alloy contains 8.67% Al and 2.51% Fe while C95300 alloy contains 10.10% Al and 0.93% Fe. Both alloys contain 0.11% Zn and trace amounts of Sn, Ni, Si, Pb. The equilibrium element that completes 100% of these two alloys is Cu. First, 99.9% pure copper was loaded into the graphite crucible of the induction furnace and the temperature was raised to 1155 degrees C. Then 99.9% pure iron filings were added, waited for 30 min and the molten metal was gently stirred with a graphite propeller shaft. At 1140 degrees C, 99.9% pure aluminium was added. A protective flux containing fluoride and chloride was used to cut off contact with the atmosphere. The melted alloys were poured without waiting into a permanent mould heated to 250 degrees C. Microstructure, SEM (Scanning Electron Microscopes), EDS (Energy-dispersive X-ray spectroscopy), XRF (X-ray fluorescence), corrosive wear, adhesive (dry) wear test samples were prepared from the appropriate regions of these alloys. The corrosive wear test was carried out with a back and forth wear system in a salt water environment containing 3.5% by weight NaCl. In the corrosive wear test, at a distance of 1000 m, alloy C95200 lost 381.48% and 152.27% more weight than alloy C95300 under 10 and 20 N load, respectively, but lost 11.98% less weight under 40 N load. When the SEM and EDS results after corrosive wear were examined, it was observed that there were cracked bright parts on the surface of the C95300 alloy. When the Adhesive dry wear results under 10, 20, 40 N loads at 8000 m distance were examined, C95200 alloy lost 5.91% more weight than C95300 under 10 N load but lost 37.25%, 60.03% less weight under 20, 40 N load respectively.
  • [ X ]
    Öğe
    Effect of casting mould on grain size and mechanical properties of X120Mn12 steel
    (Taylor & Francis Ltd, 2026) Sardogan, Berkan; Goren, Halil Ahmet; Unal, Mehmet
    This study investigated the effects of grain size variations on the microstructure and mechanical properties of austenitic manganese steels (X120Mn12), which were cast in sand and permanent moulds. The effects of the mould type on the grain size of the alloys cast without heat treatment were determined. While the permanent mould alloy was cooled in open air after casting, the sand castings were cooled in the mould. In addition to measuring the grain size, OM (Optical Microscopy), XRD (X-Ray Diffraction), XRF (X-Ray Fluorescence), SEM, EDX (Energy-Dispersive X-Ray Spectroscopy), hardness, tensile, and impact tests were performed on the produced alloys. The permanent mould had a higher cooling rate, and therefore, the samples cast in it had a more refined grain structure. Thus, we could obtain a grain structure that was likely to exhibit the desired properties. Permanent mould casting resulted in 4.46% lower hardness, 46.15% higher tensile strength, 12.30% higher yield, and 52.84% lower elongation than sand casting. The notch impact test value was 1.18% higher, while the surface roughness (Ra) was 8.98% lower in the sand mould samples than in the permanent mould samples. The sand mould samples wore 53.48% more in the abrasive wear test. Cette & eacute;tude a examin & eacute; les effets des variations de taille de grain sur la microstructure et les propri & eacute;t & eacute;s m & eacute;caniques des aciers aust & eacute;nitiques au mangan & egrave;se (X120Mn12), coul & eacute;s dans des moules en sable ou permanents. On a d & eacute;termin & eacute; les effets du type de moule sur la taille de grain des alliages coul & eacute;s sans traitement thermique. Tandis que l'on a refroidi & agrave; l'air libre l'alliage coul & eacute; en moule permanent, on a refroidi les pi & egrave;ces coul & eacute;es en moule de sable dans le moule. En plus de la mesure de la taille des grains, on a utilis & eacute; la MO (microscopie optique), la diffraction des rayons X (DRX), la fluorescence des rayons X (XRF), la microscopie & eacute;lectronique & agrave; balayage (MEB), la spectroscopie de rayons X & agrave; dispersion d'& eacute;nergie (EDX), ainsi que des essais de duret & eacute;, de traction et de r & eacute;silience sur les alliages produits. Le moule permanent pr & eacute;sentait un taux de refroidissement plus & eacute;lev & eacute;, et par cons & eacute;quent, les & eacute;chantillons coul & eacute;s dans ce moule avaient une structure granulaire plus fine. Ainsi, nous avons pu obtenir une structure granulaire susceptible de pr & eacute;senter les propri & eacute;t & eacute;s souhait & eacute;es. Le moulage en moule permanent a donn & eacute; lieu & agrave; une duret & eacute; inf & eacute;rieure de 4.46%, une r & eacute;sistance & agrave; la traction sup & eacute;rieure de 46.15%, une limite d'& eacute;lasticit & eacute; sup & eacute;rieure de 12.30% et un allongement inf & eacute;rieur de 52.84% par rapport au moulage en sable. La valeur de l'essai de r & eacute;silience apr & egrave;s entaille & eacute;tait sup & eacute;rieure de 1.18%, tandis que la rugosit & eacute; de surface (Ra) & eacute;tait inf & eacute;rieure de 8.98% dans les & eacute;chantillons moul & eacute;s en sable par rapport aux & eacute;chantillons moul & eacute;s en moule permanent. Les & eacute;chantillons du moule en sable ont subi une usure sup & eacute;rieure de 53.48% lors de l'essai d'usure abrasive.
  • [ X ]
    Öğe
    The effects of Nd, La, and Ca addition on the corrosion properties of as-cast and as-rolled ZM21 Mg alloys
    (Edp Sciences S A, 2024) Unal, Mehmet; Goren, Halil Ahmet
    In this study, the effects of Nd, La, and Ca elements added to ZM21 alloy was investigated in terms of parameters such as microscopic, mechanical, and corrosion properties. The content of each of the elemental constituents was 0.5% by weight. The microstructural and mechanical behaviours of the investigated alloys were examined by XRD, EDX, SEM, OM, hardness surveys, tensile tests, and corrosion experiments. According to the XRD results, Ca5Zn3, Ca2Mg6Zn3, LaZn2, LaMg3, Mg41Nd5, and Mg12Nd phases emerged on the investigated alloys. The grain sizes of the alloys were refined by element addition and rolling process, thus increasing their mechanical properties. Ca increased the hardness of the ZM21 alloys, but this had a negative effect on the rolled specimens. The tensile value of ZM21 alloy as cast decreased by 39.702%, 48.080%, 45.678% with the addition of (0.5% La+0.5% Nd), (0.5% La+0.5% Ca), (0.5% La+0.5% Nd+0.5% Ca), respectively. The tensile value of ZM21 alloy with (0.5% La+0.5% Nd) addition increased by 58.302% as rolled. Tensile test could not be performed because the rolled alloys with 0.5% Ca addition were fragmented during rolling. Ca contributed positively to the corrosion behaviour of the casting ZM21 alloy, but it worsened it in the rolled alloys. White oxide areas on the surface of the rolled alloys indicated an increased degree of corrosion formation.