锻造镦粗Mo-La_2O_3的横向塑性和组织  

Transverse Ductility and Microstructure of Forged and Upset Mo-La_2O_3 Bars

作　　者：陈畅[1] 汪明朴[1] 谭望[1] 张娟[1] 金鹏[1] 郭明星[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《中国稀土学报》2008年第6期724-728,共5页Journal of the Chinese Society of Rare Earths

基　　金：国家高新技术发展"863"计划项目(2006AA03Z517);湖南省自然科学基金(05JJ30095)资助项目

摘　　要：利用锻造镦粗工艺制备了高横向塑性Mo-La2O3棒材,并检测了其在退火过程中横向弯曲性能,观察了其组织结构,利用SEM进行了断口形貌分析。结果表明:Mo-La2O3棒经锻造镦粗变形85%后横向具有较好的塑性,延伸率达到了2%,在退火过程中横向塑性逐渐升高,在1200℃时延伸率达到10%以上,经1570℃退火1 h后,合金发生了再结晶,此时延伸率为1.5%;Mo-La2O3棒中形成了大量的位错胞亚结构,胞内有大量的位错缠结在一起,这些位错还被La2O3钉扎;Mo-La2O3棒经1200℃退火后,断口有"分层"现象,且断口上具有明显的河流状花样和解理台阶,断裂面上伴有大量塑性变形的韧带和撕裂岭。The forged and upset Mo-La2O3 bars have a good transverse ductility. The transverse elongation and structure of the bars were investigated by bending measurement, optical microstructure （OM） observation, scanning electron microscopy （SEM） and trans- mission electron microscopy （TEM） during annealing treatment. The results showed that the transverse elongation of the bars produced by the modified forge and upset technique reached 2%. When annealed, the transverse ductility was improved and the elongation exceeded 10% at 1200 ℃ for 1 h. However, after an-nealing at 1570 ℃ for 1 h, the elongation was only 1. 5%. Many dislocation cells could be observed in the Mo-La2O3 bars, and there still were a lot of tangled dislocations in the ceils, which were pinned by the dispersed La2O3 particles. After annealed at 1200℃ for 1 h, the fracture showed lamination effects, and the cleavage plane and the river pattern appeared on the fracture. The significant ligament bending and shearing were involved in the final separation of fracture surfaces.

关 键 词：镦粗 Mo-La2O3棒 横向塑性 分层效应 稀土 

分 类 号：TG146.4[一般工业技术—材料科学与工程]