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    Effect of Alloying Time and Heat Treatment on Microstructure and Tribological Properties of Mechanical Alloyed Cu-Al-Ni Shape Memory Alloy
    (Springer, 2023) Yavuzer, Bekir; Bicakci, Unal; Simsek, Dogan; Ozyurek, Dursun
    In this study, the effects of milling time and heat treatment on microstructure and wear behavior of Cu-Al-Ni shape memory alloys produced by the mechanical alloying method were investigated. Cu-Al-Ni shape memory alloys were produced by mechanical alloying in four different durations (2.5, 5, 7.5 and 10 h) in a planetary-type mill. The produced Cu-Al-Ni shape memory alloys were characterized by microstructure (SEM + EDS), x-ray diffraction, thermal analysis (TG/DTA-DSC), and hardness, density, and dust size measurements. In the wear tests, three different loads (10, 20, and 30 N), five different sliding distances (400, 800, 1200, 1600, and 2000 m) and a sliding speed of 1 ms-1 were used. As a result of the studies, it was observed that the powder size decreased with the increase in MA time. It was observed that the density of heat-treated shape memory alloys decreased compared only to sintered alloys. According to the wear test, the lowest wear rate was obtained in Cu-Al-Ni shape memory alloys exposed to mechanical alloying for 7.5 h, with the highest hardness value. In addition, it was observed that the wear rates decreased in heat-treated Cu-Al-Ni shape memory alloys as the sliding distance increased.
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    Effect of niobium addition on the microstructure and wear properties of mechanical alloyed Cu-Al-Ni shape memory alloy
    (Walter De Gruyter Gmbh, 2024) Yavuzer, Bekir; Turkmen, Mustafa; Bicakci, Unal; Ozyurek, Dursun
    In this study, the influence of the addition of Nb in varying amounts (0.5, 1, 1.5, and 2 wt.%) to Cu-14Al-4Ni shape memory alloy on the microstructure and wear behavior of the alloy was investigated. Cu-Al-Ni-xNb alloys were produced from elemental powders using the mechanical alloying (MA) method. The microstructures of the produced samples were examined using SEM + EDS and XRD, and density and hardness measurements were performed. For the wear tests of Cu-14Al-4Ni and alloys containing different amounts of Nb, a pin-on-disk type wear testing device was used with three different loads (10 N, 20 N, and 30 N) and five different sliding distances (400 m, 800 m, 1,200 m, 1,600 m, and 2000 m). As a result of the conducted research, it was determined that an increase in the Nb content resulted in a decrease in the average grain size and a more homogeneous grain size distribution. The highest hardness and density values were measured in the alloy with 2 wt.% Nb addition. In the wear tests, it was observed that the friction coefficients decreased with increasing load, and the lowest wear rate was achieved in the alloy with 2 wt.% Nb addition.