Yazar "Karimbaev, Ruslan" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Effect of combined shot peening and ultrasonic nanocrystal surface modification processes on the fatigue performance of AISI 304
    (Elsevier Science Sa, 2019) Amanov, Auezhan; Karimbaev, Ruslan; Maleki, Erfan; Unal, Okan; Pyun, Young-Sik; Amanov, Tileubay
    In this study, the fatigue performance of AISI 304 subjected to shot peening (SP), ultrasonic nanocrystal surface modification (UNSM) and the combination of SP + UNSM processes was systematically assessed by rotary bending fatigue (RBF) tester at different stress levels. The purpose of combining SP and UNSM processes is to find out whether SP following UNSM process can further improve the fatigue life of AISI 304 in comparison with the SP and UNSM processes alone. Interestingly, the fatigue strength of AISI 304 was deteriorated by the combination of SP + UNSM processes in comparison with the UNSM process alone, but the combination of SP + UNSM processes demonstrated a higher fatigue strength in comparison with the SP process alone.
  • Küçük Resim Yok
    Öğe
    Enhancement in microstructural and mechanical performance of AA7075 aluminum alloy via severe shot peening and ultrasonic nanocrystal surface modification
    (Elsevier, 2020) Efe, Yusuf; Karademir, Ibrahim; Husem, Fazil; Maleki, Erfan; Karimbaev, Ruslan; Amanov, Auezhan; Unal, Okan
    In this experimental study, AA7075 aluminum alloy was subjected to pure severe shot peening (SSP), pure ultrasonic nanocrystalline surface modification (UNSM) and the combination of these two treatments. The treated specimens were analyzed with detailed microstructure analysis, micro-hardness, surface roughness, XRD investigations and wear-friction tests. The results demonstrated that UNSM exhibited fine surface finish and provided minimum surface roughness with the Ra value of 0.8 limo Moreover, UNSM played an important role in the reduction of Ra as a secondary treatment. Electron back scatter diffraction (EBSD) analysis, full width at half maximum (FWHM) evaluations and compressive residual stress (CRS) measurements showed that the deformed layer structure was converted into a nanocrystallized and compressively stressed zone via SSP and UNSM. The hardness on the topmost layer was effectively enhanced by UNSM + SSP and SSP + UNSM processes. The wear and friction performance were particularly improved by two-stage operations of UNSM + SSP and SSP + UNSM. The performance was also compatible with the hardness, residual stress and nanocrystallization investigations.
  • Küçük Resim Yok
    Öğe
    An improvement in fatigue behavior of AISI 4340 steel by shot peening and ultrasonic nanocrystal surface modification
    (Elsevier Science Sa, 2020) Karimbaev, Ruslan; Pyun, Young-Sik; Maleki, Erfan; Unal, Okan; Amanov, Auezhan
    Individual and synergy effects of shot peening (SP) and ultrasonic nanocrystal surface modification (UNSM) on rotary bending fatigue (RBF) behavior of AISI 4340 steel were systematically investigated at various bending stress levels in the range of 275-600 MPa. The results revealed that the fatigue behavior of the as-received sample was enhanced by SP and it was further enhanced by SP and UNSM combination, while the UNSM-treated one exhibited the highest enhancement in fatigue behavior. The fatigue behavior of the SP + UNSM sample was enhanced after SP, but it was found to be detrimental after UNSM. Apart from RBF experiments, individual and synergy effects of SP and UNSM on surface roughness, hardness, residual stresses and grain size were analyzed as well. Fractography of the samples was characterized by scanning electron microscope (SEM) and fatigue mechanisms of each sample were discussed based on the obtained observations. The finest grain size and highest compressive residual stress (CRS) obtained by UNSM in comparison with those of the SP and SP + UNSM was responsible for the best fatigue performance.