Effect of deformation nanostructuring on thermal expansion and phase composition of Fe - 36% Ni alloy

Open School-Conference of NIS Countries Ultrafine Grained and Nanostructured Materials

Krylova, K.A.^1 ; Bitkulov, I.K.^1 ; Mulyukov, R.R.^1,2

Institute for Metals Superplasticity Problems of RAS, 39 Stepan Khalturin St., Ufa

450001, Russia^1

Bashkir State University, 32 Zaki Validi St., Ufa

450076, Russia^2

关键词: High pressure torsions;    Nano-structured;    Nano-structured Fe;    Nano-structuring;    Severe plastic deformations;    Temperature dependence;    Temperature range;    Thermal expansion coefficients;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/447/1/012015/pdf
DOI  :  10.1088/1757-899X/447/1/012015

来源: IOP

【 摘 要 】

The influence of deformation nanostructuring and subsequent annealing on the temperature dependence of the thermal expansion coefficient of the Fe-36% Ni Invar alloy is studied. The nanostructured state was obtained by severe plastic deformation via high pressure torsion in Bridgman anvils. An "anomalous" contraction of the nanostructured Fe-36% Ni alloy was detected during heating in certain temperature ranges. The phase composition of the nanostructured Invar was studied to explain the behavior of the thermal expansion coefficient. The revealed anomalies of the coefficients are explained by the formation of a bcc phase not observed in the Fe-36% Ni Invar alloy in the coarse-grained state. The formation of this phase becomes possible due to a significant increase in the diffusion coefficient as a result of nanostructuring.