论文部分内容阅读
The microstructures of Cr modified Al3 Ti containing Al2 Ti and L1o-AlTi precipitates have been investigated in terms of transmission electron microscopy (TEM). Fine precipitation of Al2 Ti (Ga2 Hf type structure) and L1o-AlTi(Cr) occurs in L12-Al3 Ti(Cr) by aging around 973K. The aging behavior was investigated by microhardness measurements. TEM observations revealed that plate-like A12 Ti precipitates lie on {100} planes of the L12-Al3 Ti(Cr) matrix with the c axis of the tetragonal phase perpendicular to the thin plate. As contrast with Al2 Ti precipitates, L1o-AlTi(Cr) precipitates form thin plate and lie on {100} planes of L12-Al3 Ti(Cr) matrix at the initial aging time and for long time aging the habit plane of the thin plate deviated from {100} plane and finally formed a kinked plate. The coherency stresses across the precipitate/matrix interface are considered to be the main factor controlling the precipitate morphology.
The microstructures of Cr-modified Al3Ti containing Al2Ti and Li-AlTi precipitates have been investigated in terms of transmission electron microscopy (TEM). Fine precipitation of Al2Ti (Ga2Hf type structure) and L1o-AlTi (Cr) occurs in L12- Al 3 Ti (Cr) by aging around 973K. The aging behavior was investigated by microhardness measurements. TEM observations showed that plate-like A12 Ti precipitates lie on {100} planes of the L12-Al3 Ti (Cr) matrix with the c axis of The tetragonal phase perpendicular to the thin plate. As contrast with Al2 Ti precipitates, L1o-AlTi (Cr) precipitates form thin plate and lie on {100} planes of L12-Al3 Ti (Cr) matrix at the initial aging time and for long time aging the habit plane of the thin plate deviated from {100} plane and finally formed a kinked plate. The coherency stresses across the precipitate / matrix interface are be the main factor controlling the precipitate morphology.