Heterogenous lamellar microstructure design to resist ductile-to-brittle transition of body-centered cubic structural metals

Abstract

The ductile-to-brittle transition (DBT) is an important characteristic that restricts the use of body-centered cubic metals as structural materials at low temperatures. This study shows a design of heterogenous lamellar microstructure (HLM), which is implemented in a low-density steel to promote the occurrence of delamination parallel to the direction of the main crack propagation, and result in delamination toughening effect. When the Charpy impact test temperature was reduced from room temperature to −196°C, the impact absorbed energy displayed a linear decline. The design of HLM brings a new pathway for developing economical BCC-structured metal plates with reliable low-temperature toughness.

Keywords

• heterogenous lamellar microstructure
• ductile-to-brittle transition
• body-centered cubic metals
• Charpy impact toughness
• delamination