Grain boundary pop-in, yield point phenomenon and carbon segregation in aged low carbon steel

Abstract

Nanoindentation measurements, tensile tests, and carbon concentration analyses were conducted to study yield behaviors in asreceived, aged, and prestrained low carbon steel. In aged sample, steel showed both yield point phenomenon (YPP) and grain boundary (GB) pop-ins besides initial pop-in, while steels in other two states showed no YPP and only the initial pop-in. 3-dimensional atom probe (3DAP) analysis in both as-received and aged samples showed that carbon content in the matrix decreased significantly after aging treatment, which is believed to contribute to the occurrence of both YPP and GB pop-in.