Stress relaxation of nickel-based superalloy helical springs at high temperatures

High-Cycle Fatigue of Nickel-Based Superalloy ME3 at Ambient and Elevated Temperatures: Role of Grain-Boundary Engineering

High-cycle fatigue (HCF), involving the premature initiation and/or rapid propagation of cracks to failure due to high-frequency cyclic loading, remains a principal cause of failures in gas-turbine propulsion systems. In this work, we explore the feasibility of using “grain-boundary engineering” as a means to enhance the microstructural resistance to HCF. Specifically, sequential thermomechanic...

A Coupled Creep-plasticity Model for Residual Stress Relaxation of a Shot-peened Nickel-base Superalloy

A COUPLED CREEP-PLASTICITY MODEL FOR RESIDUAL STRESS RELAXATION OF A SHOT-PEENED NICKEL-BASE SUPERALLOY Name: Dennis Justin Buchanan University of Dayton, 2007 Advisor: Dr. R. A. Brockman Shot peening has been employed in numerous industries for decades to impart beneficial compressive residual stresses on the surface of metal components. Compressive residual stresses retard initiation of surfa...

Modelling of Thermomechanical Fatigue Stress Relaxation in a Single-Crystal Nickel-Base Superalloy

Stretching helical nano-springs at finite temperature

Using dynamic simulations and analytic methods, we study the elastic response of a helical filament subject to uniaxial tension over a wide range of bend and twist persistence length. A low-pitch helix at low temperatures exhibits a stretching instability and the force-extension curve consists of a sequence of spikes. At elevated temperature (i.e. small persistence lengths) the helix melts and ...

Creep and Stress Relaxation Anisotropy of a Single-Crystal Superalloy