AbstractPhosphide precipitation has been studied in a Ti modified type 316 stainless steel containing a 0·15 wt-%P addition during thermal aging in the temperature range 600–800°C and as a function of initial condition (solution treated or cold worked). Needle shaped M3P precipitates in well defined crystallographic orientations are observed to nucleate on either complex defects or dislocations resulting from the initial thermomechanical condition. The stability of the phosphides decreases with increasing aging temperature and in the presence of prior cold work.MST/3239