AN HREM INVESTIGATION OF THE STRUCTURE AND DEFECTS IN TIMNSI2

Structure of and defects in TiMnSi2 intermetallic compound were studie d by high resolution electron microscopy (HREM). The reassembled recip rocal lattice from two sets of electron diffraction (ED) patterns obta ined by large angle tilt test shows that TiMnSi2 has an orthorhombic s tructure with space group Pbam. The atomic image of TiMnSi2 viewed alo ng the [001] zone direction has a tessellation of 3(2)434 type, close to that of the ''pentagon-sigma'' phase. The (010) planar faults desig nated U (upward) and D (downward) are identified. The TiMnSi2 Structur e and its defects are also verified by computer image simulation, and confirmed the results proposed earlier based on X-ray diffraction anal ysis.