Fatigue resistance and structure (30 years on)

Abstract

A B S T R A C T A summary of the findings of the 11 papers reviewed in the original article is presented, and subsequent developments in a selected few are considered from a personal perspective. While there has been substantial progress in some areas (short cracks, time-dependent effects, fatigue-creep interactions) many challenges remain. New fields of interest (notably the transition towards micro/nano-integrity and electronics applications) have emerged, and it is contended that the next 30 years will be equally demanding and exciting.Many colleagues of Keith Miller will recall his habit of landing you with 'interesting' challenges. My paper, Fatigue Resistance and Structure, was one of these. 1 It entailed summarizing 11 quite disparate presentations 2-12 made at the Extension Seminar of ICM 3 (Sheffield, 1979), and hopefully, producing something coherent. Although I rarely read my own published work, this present retrospection indicates to me that the outcome was not badothers may or may not concur. My strategy for the storyline of the paper was to consider fatigue crack initiation and propagation separately, and on a size scale covered by the 11 papers roughly atomistic (solute atoms and strain ageing) through to the macrobehaviour of laminates. Then, as probably now, uncertainty surrounded the precise interpretation of crack initiation and growth, the often different effects of microstructure on each stage and the validity of employing data from ultra-high frequency testing to more conventional applications.Following detailed consideration of each paper, the suggestions regarding how microstructural features might be utilized to improve fatigue resistance included: 1 inhibition of dislocation motion and avoidance of dislocation multiplication; 2 dispersion of plastic deformation to prevent its intensification, as in precipitate-free zones; 3 avoidance of large particles or inclusions that promoted initiation;