Nakamura N, Sakamoto M, Ogi H, Hirao M
Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
Rev Sci Instrum. 2012 Jul;83(7):073901. doi: 10.1063/1.4731657.
A method for measuring elastic constants of piezoelectric materials at high temperature up to 1224 K is proposed. It determines all independent elastic constants by measuring resonance frequencies of a rectangular parallelepiped piezoelectric specimen contactlessly using its own piezoelectricity with an antenna. Without using conventional contacting piezoelectric transducers, vibrational sources are excited directly in the specimen by the oscillating electric field. Capability of the method is demonstrated by measuring the elastic constants of langasite at high temperature up to 1224 K, and temperature coefficients of the elastic constants are determined. In addition, elastic constants of alpha quartz are measured at high temperature up to just below the alpha-beta phase transition temperature. Considering the local deformation with temperature increment, an interpretation based on the strain energy reduction is proposed for the unusual temperature dependence of C(66). Furthermore, the internal-friction tensor is measured, and the relationship between the observed anisotropy in internal friction and the structural evolution with temperature increment is discussed.
提出了一种在高达1224 K的高温下测量压电材料弹性常数的方法。该方法通过使用天线利用长方体压电试样自身的压电性非接触地测量其共振频率来确定所有独立的弹性常数。无需使用传统的接触式压电换能器，振荡电场直接在试样中激发振动源。通过测量高达1224 K高温下硅酸镧镓的弹性常数证明了该方法的能力，并确定了弹性常数的温度系数。此外，在高达α-β相变温度以下的高温下测量了α石英的弹性常数。考虑到随温度升高的局部变形，针对C(66)异常的温度依赖性提出了基于应变能降低的解释。此外，测量了内耗张量，并讨论了观察到的内耗各向异性与随温度升高的结构演化之间的关系。
