Ductile-brittle transition in a 9% Cr heat-resistant steel
Published on Jan 13, 2017in Materials Science and Engineering A-structural Materials Properties Microstructure and Processing5.234
· DOI :10.1016/J.MSEA.2016.11.035
Abstract The mechanical behavior of a P92-type steel was studied by tension and Charpy impact tests in the temperature range of 77–293 K. The yield stress (YS) and uniform elongation increase concurrently with decreasing temperature because the steel exhibits work-hardening behavior. Transgranular dimpled fracturing remains the primary fracture mechanism under tension down to 193 K. Brittle fracture takes place at lower temperatures. At 77 K, the steel exhibits a well-defined yield plateau. Impact tests demonstrate that the ductile-brittle transition (DBT) occurs at 210 K. At 193 K, the energy absorption of 110 J/cm 2 at high impacts is attributed to extended areas of crack initiation and a stable crack propagation; the fast fracture load also has a high value. The steel becomes completely brittle at 77 K, at which temperature the absorbed energy falls to 6 J/cm 2 .