QUASI-STATIC DEFORMATION-BEHAVIOR OF PURE SINTERED IRON IN THE TEMPERATURE-RANGE BETWEEN -184-DEGREES-C AND 600-DEGREES-C

The deformation behaviour of pure sintered iron materials with densiti es between 6,88 und 7,57 g/cm(3) was investigated in tension tests in the temperature range of -184 and 600 degrees C. Supplementary compres sion tests were carried out at 20 degrees C. Increasing density leads to increasing material resistances and ductility properties due to the increase of the bearing specimen cross sections as well as due to sma ller numbers of pores, more spherical pores with smaller notch effects and smaller numbers of mircocracks, which are initiated at pores. Aft er equal deformations, due to pore closing effects and the impediment of crack initation, the flow stresses of compressively deformed specim ens are larger than those of tensily deformed. The deformation behavio ur is dominated at low temperatures by thermal activated glide process es of dislocations and their interactions with short range obstacles, at middle temperatures by dynamic strain ageing due to elastic interac tions of glide dislocations and diffusing carbon atoms and at high tem peratures by recovery controlled dislocation creep processes.