High Strain-Rate Behavior and Transformation-Induced Plasticity of a High-Strength FeCrMoVWC Alloy Manufactured by Rapid Solidification Technique

By employing the rapid solidification technique and special manufacturing conditions, e.g., using only pure elements, an alloy was produced that exhibits major differences to conventionally produced high-speed steels. Within this study, the strain rate dependent material behavior of the examined alloy was characterized under compressive loading for a strain rate range from 10−3 seconds−1 to 103 seconds−1. The aim was to understand the inherent mechanisms when low and high strain rates are applied. Initially, microstructural observations of the base material, which revealed α’-martensite, retained austenite, and complex carbides, were conducted. The material exhibits extraordinarily high ultimate compression strength of up to 4800 MPa, a high work-hardening behavior, and a good deformability of 15 pct. Moderate strain rate sensitivity was detected. Furthermore, a strain-induced transformation (transformation induced plasticity [TRIP]-effect) from retained austenite to α’-martensite occurred. Interrupted compression tests at different strains and strain rates were carried out to understand the microstructural evolution. The examinations showed that adiabatic heating decreases the transformation rate of retained austenite to α’-martensite and counteracts the work-hardening behavior. For higher strain rates higher α’-martensite contents in the initial deformation region as well as a pronounced saturation behavior of α’-martensite was detected. A hypothesis is given for the strong work-hardening behavior of the alloy.