A Transforming Metal Nanocomposite with Large Elastic Strain(4)

REPORTS

Fig.3.TypicalmacroscopicmechanicalpropertiesofNICSMA.(A)Tensilestress-straincurvesofapre-treatedNICSMAat15°,30°,and50°C.sS,yieldstrength;E,Young’smodulus;ee,elasticstrainlimit.(B)Cyclictensilestress-straincurvesofapretreatedNICSMAatroomtemperature.(C)Comparisonoftheyieldstrengthsandelasticstrainlimitsofdif-ferentmaterials.(D)ComparisonoftheyieldstrengthsandYoung’smoduliofdifferentmaterials.

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Fig.4.MicroscopicresponsesofNICSMArevealedbyinsitusynchrotronHE-XRD.(A)Evolutionofthed-spacingstrainforNb(220)andB2-NiTi(211)planesperpendiculartotheloadingdirectionduringthepretreat-ment.(Inset)Themacroscopicstress-straincurveofthepretreatment.(B)EvolutionofthediffractionpeaksofNb(220),B2-NiTi(211),andB19′-NiTi(001)duringthepretreatment.(C)Evolutionofthed-spacingstrainforNb(220)planeperpendiculartotheloadingdirectionduringthesubsequenttensilecycle.(Inset)Thecyclicstress-straincurve.(D)

tiveintensityoftheB19′-NiTi(001)diffractionpeakduringthesubsequenttensilecycle.TherelativeintensityisdefinedastheratiooftheintegratedareaoftheB19′-NiTi(001)diffractionpeakatagivenappliedstraintothatoftheB19′-NiTi(001)diffractionpeakatthemaximumappliedstrain.(E)EvolutionofthediffractionpeaksofNb(220),B2-NiTi(211),andB19′-NiTi(001)duringthesubsequenttensilecycle.TheB2-versus-B19′peakintensitychangescontinuously,indicatingcontinuousSIMTthroughoutthetensileloading.VOL339

8MARCH2013

SCIENCE1193