The grain boundary effect on the strength was evaluated through nanoindentation technique for Fe-0.4C-Cr-Mo steels that were produced by the ausform-tempered (AF) and conventional quench-tempered (QT) processes. A semiquantitative Hall-Petch plot was made to determine the locking parameter k for the two alloys using nanohardness, micro-Vickers hardness, and grain size. The k value for the QT sample is significantly larger than that for the AF sample and is attributed to the film-like carbides on the grain boundaries of the QT sample. The lower k value of the AF sample is one of the factors for the improved delayed fracture property in the AF compared to that of the QT sample.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering