DISLOCATION ARRANGEMENTS IN SINGLE-CRYSTALLINE SILICON FATIGUED IN TENSION COMPRESSION/

Preliminary results of low-cycle fatigue experiments at high temperatu res on [123] silicon single crystals are reported. The effects of temp erature (from 1073 to 1373 K), plastic strain rate (from 5 x 10(-5) to 5 x 10(-3) s(-1)) and plastic strain amplitude (10(-3) and 5 x 10(-3) ) on the mechanical behaviour are investigated. At low temperature and high strain rate, fracture took place after about 100 cycles, while s aturation of the maximum stress could be reached at higher temperature s and lower strain rates. Transmission electron microscopy (TEM) obser vations reveal that a cellular arrangement of dislocations is associat ed with the latter case while loop-patches are characteristics of the former. (C) 1997 Elsevier Science S.A.