The Assessment of a Material Life Cycle Based on an Analysis of Fracture Surfaces after Fatigue Failure

Abstract

The service life of machine components exposed to cyclic loading below a yield point is a very significant factor for the assessment of material properties. One of the methods of enhancing material resistance to the initiation and course of a fatigue process is changing the chemical composition of the material surface layer. The paper is concerned with the prolongation of the life cycle of military vehicles machine components by means of a new technology based on the combination of chemical-heat (plasma nitriding) treatment and heat treatment with emphasis put on the increase in the fatigue strength and service life (resistance to corrosion) of originally soft-annealed steel ČSN 412061. The new technology allows reducing the probability of limit state occurrence in a component thus optimising financial means of the Armed Forces of the Czech Republic.