Development of thermomechanical processing method to enhance twinning in commercially pure Zr

Abstract

Zirconium is widely used as fuel cladding material in nuclear power reactors. Here, a thermomechanical processing technique has been developed and implemented to improve the mechanical properties of commercially pure Zr-702. In the process the twin density increased to 45 areal%. The twins were identified to be mostly of {10 (1) over bar2) < 10 (1) over bar(1) over bar > tensile twins or {10 (1) over bar1} < 10 (1) over bar2 > compression twins. The significant increase in hardness was analyzed for its contributing factors and was attributed to the microstructural refinement caused by twin boundaries. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.