工业纯钛ECAP温变形的组织研究

Microstructure of Ti Processed by ECAP at Intermediate Temperature

采用两通道夹角为90°,外圆角为20°的模具,实现了工业纯钛BC方式6道次的ECAP温变形,累积等效真应变达到6.3,并观察分析了变形试样的显微组织。结果表明:工业纯钛经BC方式6道次ECAP温变形后,获得了晶粒尺寸为150nm的具有大角度晶界的超细晶组织;工业纯钛在ECAP温变形过程中,随变形道次的增加,通过位错滑移产生的板条和不稳定的孪晶组织相互作用,大量的位错聚积成位错胞并生成亚晶;在变形温度的影响下,位错相互作用,使亚晶逐渐演变成具有大角度晶界的超细晶组织。

Commercial pure titanium （CP-Ti） was carried by ECAP for six passes at intermediate temperature with rout BC, using the die with internal angle 90° and outer curvature angle 20°. The equivalent strain is up to 6.3. Meanwhile, the microstructure of deformation specimen and the effects of the passes and annealing temperature on the microstmcture and mechanical properties were investigated. The results show that UFG with high-angle boundaries and the instability twins are generated and the average grain size is about 150 nm are six intermediate-ECAP passes.