摘要
Upon uniaxial compressive loading at 500℃(T/Tm=0.67,where Tm is the absolute melting point),the n-type Skutterudite alloy Yb03Co4Sb12 deforms plastically by creep via a power-law,with a stress exponent~3 consistent with dislocation viscous glide.An activation energy of 171 kJ/mol is measured over the temperature range of 500-587℃(T/Tm=0.67-0.75)at a stress of 30 MPa.Yb_(0.3)Co_(4)Sb_(12)is ductile at 500℃,exhibiting a compressive strain of 25%when subjected to stresses ranging from 22 to 90 MPa for up to 28 days.Among the thermoelectric materials tested so far for creep,Yb_(0.3)Co_(4)Sb_(12)exhibits a creep resistance intermediate between low-melting(Bi2Te3,TAGS-85)and high-melting thermoelectrics(Mg2Si and ZrNiSn).A relatively modest drop in the figure of merit zT,from 0.67 to 0.52,is displayed by Yb_(0.3)Co_(4)Sb_(12)after accumulating 3.7%compressive creep strain at 500℃,mostly due to a drop in electrical conductivity.
基金
supported by the NASA Science Missions Directorate’s Radioisotope Power Systems Technology Advancement Program.This work made use of the MatCI Facility which receives support from the MRSEC Program(NSF DMR-1720139)of the Materials Research Center at Northwestern University.This work made use,as well,of the EPIC facility of Northwestern University’s NUANCE Center,which has received support from the Soft and Hybrid Nanotechnology Experimental(SHyNE)Resource(NSF ECCS-1542205)
the MRSEC program(NSF DMR-1720139)at the Materials Research Center
the International Institute for Nanotechnology(IIN)
the Keck Foundation
the State of Illinois,through the IIN.This work also made use of the IMSERC at Northwestern University,which has received support from the Soft and Hybrid Nanotechnology Experimental(SHyNE)Resource(NSF ECCS-1542205)
the State of Illinois and International Institute for Nanotechnology(IIN).GJS Acknowledges support from the NASA Science Mission Directorate’s Radioisotope Power Systems Thermoelectric Technology Development program.
