Hardening of Surface Layers of Cu–39Zn–1Pb Brass at Holding and High-Frequency Impact Deformation in Liquid Nitrogen
M. O. Vasylyev$^{1}$, B. M. Mordyuk$^{1}$, S. M. Voloshko$^{2}$, V. I. Zakiyev$^{3}$, A. P. Burmak$^{2}$, D. V. Pefti$^{2}$
$^{1}$G. V. Kurdyumov Institute for Metal Physics, NAS of Ukraine, 36 Academician Vernadsky Blvd., UA-03142 Kyiv, Ukraine
$^{2}$National Technical University of Ukraine ‘Igor Sikorsky Kyiv Polytechnic Institute’, 37 Peremohy Ave., UA-03056 Kyiv, Ukraine
$^{3}$National Aviation University, 1 Cosmonaut Komarov Ave., UA-03058 Kyiv, Ukraine
Received: 10.07.2019. Download: PDF
The microhardness $HV$ changes of the surface layers of biphasic brass Cu–39Zn–1Pb are experimentally investigated depending on the duration of exposure in the liquid nitrogen and on the time of cryogenic ultrasonic impact treatment (cryo-UIT) under quasi-isostatic conditions. As shown, the strengthening effect for the brass surface is $\cong$1.8–2 times under cryo-deformation conditions and the maximum $HV$ value of 3.34 GPa is reached after cryo-UIT for 10 s. The effect of strengthening is registered at a depth up to $\cong$1 mm. After cryo-UIT, the changes in the instrumental hardness, $H_\textrm{IT}$, Young’s modulus, $E$, and the plasticity characteristics, $\delta_H$, of the surface layer material are established by means of instrumental indentation method. Taking into account the data of X-ray analysis, possible factors of the detected strain hardening are analysed.
Key words: brass, ultrasonic impact treatment, cryo-deformation, microhardness, elastic modulus, plasticity characteristics, instrumental indentation.
URL: http://mfint.imp.kiev.ua/en/abstract/v41/i11/1499.html
DOI: https://doi.org/10.15407/mfint.41.11.1499
PACS: 43.35.+d, 62.20.Qp, 81.40.Ef, 81.65.-b, 81.65.Lp, 83.10.Tv
Citation: M. O. Vasylyev, B. M. Mordyuk, S. M. Voloshko, V. I. Zakiyev, A. P. Burmak, and D. V. Pefti, Hardening of Surface Layers of Cu–39Zn–1Pb Brass at Holding and High-Frequency Impact Deformation in Liquid Nitrogen, Metallofiz. Noveishie Tekhnol., 41, No. 11: 1499—1517 (2019) (in Ukrainian)