高温变形FeAl金属间化合物中的位错特征

DISLOCATION FEATURES IN FeAl INTERMETALLIC COMPOUND AFTER DEFORMATION AT HIGH TEMPERATURE

利用透射电子显微镜对９００℃高温变形后的ＦｅＡｌ金属间化合物进行观察，发现材料中存在大量的方形位错环和位错蜷线偶．经确定，方形位错环位于（１００）面，Ｂｕｒｇｅｒｓ矢量为［１００］，是由空位聚集造成的．位错蜷线偶是由［１１１］螺型位错偶经过攀移形成的．有迹象表明，位错进一步攀移，可使位错蜷线偶产生另外一种与其具有相同Ｂｕｒｇｅｒｓ矢量的位错环，这种位错环位于与蜷线轴线垂直的面上．作者认为，位错的攀移运动是ＦｅＡｌ金属间化合物高温塑性好的主要原因．

The dislocation features in FeAl intermetallic compound deformed at 900℃have been investigated by TEM.A large number of sqaure dislocation loops and helical dipoles have been found.The loops are identified to have the Burgers vector[100] and lie on(100)planes due to vacancy condensation. The helices are identified to have the Burgers vector [111] and result from the climb process of screw [111] dislocation at high temperature.One evidences indicate that further climb of the helical dipoles could result in another kind of loop which has the same Burgers vector as the dipoles and lies on the planes perpendicular to the Burgers vector.It is assumed that the climb of dislocation is responsible for the high ductility of FeAl compound at high temperature.