Strain Fatigue Behavior of Thin-Walled Tubes of Zr-1Nb and Zr-4 and Thin Plates of N18 at Elevated Temperatures
Thin plates and small thin-walled tubes of zircaloys are used as fuel cladding materials of nuclear reactors. In order to prevent buckling of plate or tube specimens of zircaloys under cyclic strain loading, a set of self-invented clamps were used for strain fatigue tests of small thin-walled tubes of Zr-4 and Zr-1Nb at elevated temperature. Depending on axial control strain, a new strain fatigue test method named as (equivalent strain)-SF(strain fatigue) was developed for thin funnel-like plate specimens of N18 zircaloy with double side notches. A series of monotonic tension tests for the three kinds of zircaloys at different temperatures and strain fatigue tests for Zr-4 and Zr-1Nb at 375°Cand for N18 at 20°C,300°Cand 500°C were carried out. Monotonic and cyclic constitutive relations and Manson-Coffin life-estimating expressions for these zircaloys are given. ES-SF method has no Poisson effect and has better accuracy to predict strain fatigue behavior.
Q. Jia et al., "Strain Fatigue Behavior of Thin-Walled Tubes of Zr-1Nb and Zr-4 and Thin Plates of N18 at Elevated Temperatures", Applied Mechanics and Materials, Vol. 69, pp. 39-44, 2011