Thermal fatigue failure mechanisms and enhancement strategies of die steel

Thermal fatigue failure is the core issue that restricts the development of die-casting technology, and it directly impacts the lifespan of the dies and the resulting economic benefits. This article reviews the fundamental mechanisms of thermal fatigue failure of die steels, classifies the potential failure mechanisms and discusses them in detail. This article examines the pivotal factors that affect the thermal fatigue resistance of die steels from four perspectives: alloying elements, processing techniques, microstructure, and inherent properties. On this basis, this article summarizes the advantages and disadvantages of various methods to enhance thermal fatigue resistance, such as alloying element optimization, heat treatment process, surface treatments, and nanoparticle strengthening. Moreover, this article summarizes the thermal fatigue life prediction model of die steels and offers insights into prospective development trends and research directions of enhancing the thermal fatigue resistance of die steels. It is hoped that this review can fully explain the causes of thermal fatigue failure of die steels and provide directions for the development of high-performance, high-stability and long-life die steels.