Mechanical Properties of Nanostructured and Ultrafine Grained Steel

摘要

This work is focused on the evaluation of macroscopic mechanical properties of near fully densernnanostructured and ultrafine grained bulk samples of low and medium carbon steel (0.04 torn0.60%C). The specimens were obtained by warm static pressing from mechanically milledrnpowder at temperatures between 400 ℃ and 500 ℃. Subsequently, some samples were heatrntreated between 700 ℃ and 775 ℃ in order to get a wide range of grain size.rnThe evaluation of the samples includes density, grain size and hardness. In addition, results ofrnroom temperature compression tests are compared and discussed in terms of microstructurernand strain hardening behaviour. The increase in hardness at decreasing grain sizes wasrnsignificant and in good agreement with the Hall-Petch relation. A noticeable increase in strengthrnat increasing carbon percentage was also observed.