摘要
Deformation mechanisms and magnetic properties of medium and high entropy alloys(MEA/HEAs)closely relate to lattice distortion and are strongly temperature-dependent,in particular,at low temperature ranges.However,little attention has been paid to the evolution of lattice distortion with temperature decreasing and its effects on deformation behavior and magnetic state transition.In this work,we carry out in situ synchrotron radiation based X-ray powder diffraction(SR-XRD)experiments from 293 to 123 K aiming for determining lattice distortion evolutions of Cr Co Ni MEA,Cr Fe Co Ni and Cr Mn Fe Co Ni HEAs.Magnetic measurements at corresponding low temperatures and cryogenic ranges are further conducted.The in situ SR-XRD results demonstrate a general reduction of lattice distortion magnitude with temperature decreasing,which shows a similar tendency with that of reported stacking fault energy(SFE)values.It is thus suggested that lattice distortion reduction possibly makes a critical contribution to deformation mechanism transition.The magnetic measurement results show a clear ferromagnetic transition of Cr Fe Co Ni HEA when temperature is below 173 K.While,no obvious magnetic state transition is observed for Cr Co Ni MEA and Cr Mn Fe Co Ni HEA.The present findings on lattice distortion evolutions will pave the way for designing targeted HEAs with particular properties.
基金
financially supported by the National Key Research and Development Program of China(No.2017YFB0702003)
the National Science Foundation of China(Nos.12002341,11790292 and 11672316)
the NSFC Basic Science Center Program for“Multiscale Problems in Nonlinear Mechanics”(No.11988102)
the Strategic Priority Research Program(Nos.XDB22040302 and XDB22040303)
the Key Research Program of Frontier Sciences(No.QYZDJSSWJSC011)
the Science Challenge Project(No.TZ2016001)
the Zhejiang Provincial Natural Science Foundation(No.LGG21E010005)。
