Acoustic methods for characterisation of microstructures and deformation processes in Nimonic alloy PE 16 and Zircaloy-2

Abstract

This paper discusses the experience of the authors in using ultrasonic attenuation and velocity measurements and acoustic emission technique for characterisation of micro-structures and deformation processes in Nimonic alloy PE 16 and Zircaloy-2. It is possible to assess the volume fraction of γ' in Nimonic alloy PE 16 using ultrasonic velocity measurements. Acoustic emission technique is useful to monitor the influence of presence of secondary phases γ' and MC independently and also their conjoint presence on tensile deformation. In Zircaloy-2. low frequency ultrasonic velocity measurements are useful for detecting presence of hard intermetallics and high frequency velocity measurements are useful for revealing the early stage dissociation of β quenched microstructure to α phase. Also, assessment of hydrogen concentration in the range 25 to1100 mg/kg in Zircaloy-2 is possible using ultrasonic velocity ratio (longitudinal to shear) obtained from the precise ultrasonic transit time measurements.