Grain growth behavior of an as-drawn 316L stainless steel fiber after annealing treatment

Isothermal annealing treatments for as-drawn 316 L stainless steel fibers with a diameter of 20 μm were performed at the temperatures from 800 to 950 °C with the holding times from 5 to 30 min. OM observations, XRD and EBSD techniques were used to examine the evolution of grains, phase constitutions, misorientation distribution and texture, respectively. Grain growth of the fiber is found to be potentially influenced by the texture and the diameter of fiber. The grain growth exponent n increases at first and then decreases with the increasing temperature. After annealing, the relative frequencies of LAGBs decrease due to recrystallization. The relative frequency of Σ3 boundaries in the microstructures of the annealed fibers apparently increase compared with that of the as-drawn fiber. But with the recrystallization proceeding, the variation of Σ3 boundaries shows the same trend with annealing temperature or holding time as that of the LAGBs. The emergence of high frequencies of Σ3 boundaries accelerates the growth of < 100 > and < 111 > grains during recrystallization. The < 111 > orientation becomes dominant at the temperature of 900 °C. With the time extending to 20 min, an almost single < 111 > component is exhibited in the microstructure of the fiber, which provides a favorable condition for the occurrence of abnormal grain growth.