High-temperature anelastic behavior of silicathrough the α-β phase transition

【摘要】：正Four different silica samples:single crystal quartz cut parallel with[100]and[001],polycrystalline Arkansas novaculite and Permian sandstone from Arran,Scotland,have been investigated by Dynamic Mechanical Analyzer(DMA),which is essentially a three-point bending system,to measure the storage modulus and mechanical loss during heating and cooling through theα-βphase transition.Single crystal quartz samples,which were separately cut along the[100]and[001]direction,display different temperatures for the first-orderα-βtransition due to anisotropic strain along different orientation under external stress.The polycrystalline novaculite with grain size 1～5μm exhibits characteristics of a second-order phase transition,and it shows 6℃higher transition temperature than single crystal quartz,which is related to the internal pressure caused by anisotropic