High-temperature creep behavior and related interfacial phase transformation of titanium/steel clad plates

Titanium/steel clad plates are primarily used in condensers in the nuclear energy sector, where they endure high-temperature and high-pressure conditions during service. However, the high-temperature creep mechanisms of titanium/steel clad plates are not yet adequately understood. To address this issue, uniaxial tensile creep tests were conducted on TC4/304 clad plates at a temperature of 500°C during this study. The results indicate that, as the stress increased from 300 MPa to 500 MPa, the steady-state creep rates of the specimens rose accordingly and that the stress exponent reached a value of 14.04. This result suggests that the creep behavior in this regime was primarily controlled by dislocation creep mechanisms. Significant deformation-induced martensitic transformation occurred in the 304 stainless-steel matrix. The austenite content increased with the applied stress, while the martensite content, which was governed by the time-dependent cumulative effects of the creep, exhibited the opposite trend. Moreover, a notable stress–time coupling effect was observed; elemental migration occurred more extensively under prolonged low-stress conditions, and various interfacial phases, such as FeCr, TiV, FeNi, and Ti2Ni, were formed.