000 03627nab a2200361 c 4500
001 koha000997185
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007 cr |
008 230221|2022 ne s a eng d
024 7 _a10.1016/j.msea.2022.143586
_2doi
035 _akoha000997185
040 _aRU-ToGU
_brus
_cRU-ToGU
245 1 0 _aCritical resolved shear stress for twinning and twinning-induced plasticity in single crystals of the CoCrFeNiMo0.2 high-entropy alloy
_cI. V. Kireeva, Yu. I. Chumlyakov, A. V. Vyrodova, A. A. Saraeva
336 _aТекст
337 _aэлектронный
504 _aБиблиогр.: 67 назв.
520 3 _aThe effect of alloying with Mo atoms 4 at.% on the twinning deformation, critical resolved shear stresses (CRSS) for slip τslcr and twinning τtwcr and plasticity was studied in [111]-, [144]- and [001]- oriented crystals of the Co24Cr24Fe24Ni24Mo4 (at.%) high-entropy alloy (HEA) under tension at 296 and 77 K. The stacking fault energy of the Co24Cr24Fe24Ni24Mo4 HEA, measured in the resent paper on the triple dislocation nodes, is equal to 0.027 J/m2. It is shown that initial yield behavior along studied orientations is governed by dislocation slip and the CRSS for slip are independent of crystal orientation. Under tensile strain, twinning develops in the [111]- and [144]- oriented crystals only at 77 K and is not detected in the [001]-oriented crystals. Two types of twins are found in the [111]- and [144]-oriented crystals (thin nanotwins and macrotwins). Nanotwins develop after a low slip deformation of 5–10% and are observed only by transmission electron microscopy. Macrotwins are detected after a significant slip deformation of 20 and 60% and are determined metallographically and X-ray by the precession of the crystal axis, respectively, in the [111]- and [144]-oriented crystals. In the [111]- oriented crystals, there is no precession of the crystal axis due to the development of slip simultaneously in several systems. It is shown that CRSS for nano- and macrotwins are dependent on the crystal orientation. In the [144]-oriented crystals, τtw cr = 212 MPa for nanotwinning and τtw cr = 400 MPa for macrotwinning. In the [111]-oriented crystals, τtw cr = 250 MPa for nanotwinning and τtw cr = 335 MPa for macrotwinning. For the transition to deformation by macrotwinning, it is necessary that the effective stacking fault energy γef is approaching to zero and the condition τtwcr <τslcr is satisfied. Deformation by macrotwinning suppresses slip multiplicity and shifts the formation of the neck formation according to the Consid`ere condition to higher stress levels. This increases plasticity from 72% at 296 K to 108% at 77 K in [144]-oriented crystals and from 48% at 296 K to 57% at 77 K in [111]-oriented crystals.
653 _aвысокоэнтропийные сплавы
653 _aмонокристаллы
653 _aдеформация растяжения
653 _aдеформационное двойникование
653 _aпластичность, вызванная двойникованием
655 4 _aстатьи в журналах
_9877202
700 1 _aKireeva, Irina V.
_cфизик
_989594
700 1 _aChumlyakov, Yuri I.
_9100866
700 1 _aVyrodova, Anna V.
_9877230
700 1 _aSaraeva, Anastasia A.
_9877232
773 0 _tMaterials science and engineering A
_d2022
_gVol. 850. P. 143586 (1-15)
_x0921-5093
852 4 _aRU-ToGU
856 4 _uhttp://vital.lib.tsu.ru/vital/access/manager/Repository/koha:000997185
908 _aстатья
999 _c997185