MECHANICAL PROPERTIES OF Ti_3SiC_2 AT HIGH TEMPERATURE

摘要

Creep and stress relaxation behavior, the elastic modulus and fracture toughness of machinable Ti_3SiC_2 at various temperatures from 20℃ to 1250℃ were investigated by means of three-point bending tests. The experiments were performed respectively at: ⅰ) fixed stress and changed temperatures, and ⅱ) fixed temperature and changed stresses. A creep resistance parameter that represents the probability of creep deformation in a given condition was defined as a function of both applied stress and the threshold stress, varying in a range from 0 to 1. Elastic modulus at high temperatures was measured through comparing relative slopes of loading curves in cyclic loading curve. The fracture toughness measured by SENB method showed a stable value in the range of 25-1000℃, but over 1000℃, it declined abruptly from ～6.7 MPa · m~(1/2) to ～2.0 MPa · m~(1/2) at 1200℃.