An in situ observation of the s'phase morphology and its orientation with the matrix in an Al-Li base alloy was carried out by means of double-tilt rotating around[220]a in a transmission electron microscope(TEM)....An in situ observation of the s'phase morphology and its orientation with the matrix in an Al-Li base alloy was carried out by means of double-tilt rotating around[220]a in a transmission electron microscope(TEM).The results show that the s'phase precipitates in the form of bundles.The units of s'phase are lath-shaped,grow along the<100>,orientation,and have habit planes of{210}*.Many units of the s'phase grow in the same orientation and get together to form a plate-shaped bundle of s'phase laths which lie on the{110}a planes.展开更多
The precipitation of S'phase in an 8090 Al-Li alloy under various aging conditions was investigated by transmission electron microscopy.The results show that a small quantity of S'precipitates precipitated on ...The precipitation of S'phase in an 8090 Al-Li alloy under various aging conditions was investigated by transmission electron microscopy.The results show that a small quantity of S'precipitates precipitated on the grain and subgrain boundaries for the specimens aged to peak hardness during single aging.Cold working prior to aging promoted the widespread precipitation of S'phase because of increasing dislocation density.In natural aging the vacancies bound by Li atoms were released and formed dislocation loops.S'precipitates preferentially nucleated and grew on the dislocation loops.展开更多
文摘An in situ observation of the s'phase morphology and its orientation with the matrix in an Al-Li base alloy was carried out by means of double-tilt rotating around[220]a in a transmission electron microscope(TEM).The results show that the s'phase precipitates in the form of bundles.The units of s'phase are lath-shaped,grow along the<100>,orientation,and have habit planes of{210}*.Many units of the s'phase grow in the same orientation and get together to form a plate-shaped bundle of s'phase laths which lie on the{110}a planes.
文摘The precipitation of S'phase in an 8090 Al-Li alloy under various aging conditions was investigated by transmission electron microscopy.The results show that a small quantity of S'precipitates precipitated on the grain and subgrain boundaries for the specimens aged to peak hardness during single aging.Cold working prior to aging promoted the widespread precipitation of S'phase because of increasing dislocation density.In natural aging the vacancies bound by Li atoms were released and formed dislocation loops.S'precipitates preferentially nucleated and grew on the dislocation loops.