Outstanding impact toughness of low-alloyed steel with fine lamellar microstructure

Abstract

Abstract A low-carbon low-alloyed steel subjected to tempforming exhibited high strength and outstanding impact toughness (KCV). The latter surprisingly increases from 412\xa0J\xa0cm−2 at room temperature to 426\xa0J\xa0cm−2 at 183\xa0K. Such an unusual behaviour is attributed to delamination toughness, which is provided by the ultrafine lamellar microstructure. Namely, the rapid delamination crosswise to the impact direction blunts the crack and significantly increases the impact toughness.