Pre-ratcheted Tensile Properties of Nickel Base Alloy IN-617 at RT

In advanced ultra-super-critical power plants, Inconel (IN)-617, a nickel base superalloy, is regarded as a material of primary significance. The current study is on the role of prior ratcheting on tensile properties of IN-617 alloy in solution-treated condition. Specimens were subjected to uniaxial asymmetrical cyclic stressing for 200 cycles, at room temperature (RT), at different amplitudes of stress (sigma(a)), mean stress (sigma(m)), and stress rate ((sigma) over dot). The pre-ratcheted specimens were tested in tension at 10(-3) s(-1). There was marked increase in yield strength and tensile strength due to prior cyclic ratcheting, but fall in ductility. The increase in strength was due to the work hardening and the fall in ductility from exhaust of ductility, due to cyclic ratcheting during the prior 200 cycles.