Electron microscopy study of two new long period structures in Pt_xTi alloys (3 ≦ x ≦ 8)

Alloys with compositions varying between Pt₈Ti and Pt₃Ti are studied by means of electron diffraction and high resolution electron microscopy. The Pt₈Ti superstructure is confirmed and it is found that also in this case the light minority atoms can be revealed in high resolution images a bright dots under suitably chosen imaging conditions. Two new long period antiphase boundary structures based on the face centered cubic structure are determined: a) an orthorhombic one‐dimensional superstructure with composition Pt₁₃Ti₂ and b) a tetragonal two‐dimensional superstructure with composition Pt₂₁Ti₄. Descriptions of several faults in the microtexture of these superstructures are given.