辉长岩脆-塑性转化及其影响因素的高温高压实验研究

AN EXPERIMENTAL STUDY ON THE BRITTLE-PLASTIC TRANSITION IN GABBRO

本文利用高温高压多功能三轴实验装置 ,以NaCl为固体围压传压介质 ,在围压为 45 0MPa～ 80 0MPa ,温度区间为 6 0 0℃～ 1 1 5 0℃和应变速率为 1× 1 0 - 4～3 1 2 5× 1 0 - 6 s条件下 ,对攀枝花辉长岩进行了流变学实验研究。实验结果表明 ,辉长岩围压在 45 0MPa～ 80 0MPa条件下 ,温度在 6 0 0℃时为脆性变形 ,70 0℃～ 85 0℃时为半塑性流动 ,含微破裂 ,大于 90 0℃时为塑性流动。辉长岩的脆 塑性转化温度为 70 0℃～ 90 0℃ ,主要影响因素为温度、围压和应变速率 ,同时存在双相流变学问题。

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.