AN EXPERIMENTAL STUDY ON THE BRITTLE-PLASTIC TRANSITION IN GABBRO

In this paper,an experimental study of brittle-ductile transition in Panzhihua fine grained gabbro was performed under a Griggs-type apparatus with NaCl as the confining pressure medium. Experiments were conducted in conditions of:450MPa~800MPa confining pressure,600℃~1150℃ temperature,and 1×10^-4~3.125×10^-6/s strain rate.The results of experiments show that the deformation of the gabbro is brittle fractures at temperature 600℃,semibrittle flow at 700℃~850℃,and plastic flow at temperature higher than 900℃.The temperature of brittle plastic transition is 700℃~900℃ at the confining pressure 450MPa~800MPa.The major factors that influence the brittle-plastic transition in the gabbro are temperature and strain rate,and the influence of confining pressure is secondary.