Dislocation Mechanisms and Local Strength with a View towards Sleeper Screw Failures

Dislocation structures can be directly related to the fatigue properties of metals, such as strength, including limit and saturation stress. We present an indirect dislocation-structure-based method evaluate local stresses for in-depth analysis sleeper screw failures, there is little knowledge about load these failures. The screw, fastening baseplates rails sleepers, a small but critical component in railway. High loads from passing trains are transferred screws, leading cyclic straining. In study, three stress-level tension experiments designed constant stress mode at ratio R = 0 testing frequency 10 Hz. microstructures failed specimens characterized compared with those close fracture surface screws that field. dislocation structure similarities differences analyzed, potential proposed methodology discussed.