RECOVERY OF HIGHLY STRAINED FE-28 AT.-PERCENT-AL ALLOY

Recovery of a highly strained Fe-28 at.-% Al alloy has been studied by means of electrical resistivity, Mossbauer spectroscopy, magnetic polarisation, and coercivity measurements. The amount and state of defect rich volumes (interfacial phase) were investigated. Three recovery steps were found in the temperature dependences of resistivity and magnetic polarisation. The first two steps are characterised by almost the same activation energies (epsilon1 = 120 +/- 5 and epsilon2 = 127 +/- 1 kJ mol-1) derived from resistivity measurements, and can be ascribed to the annihilation of defects and relaxation of stresses accompanied by cell wall sharpening and the onset of subboundary formation. The appearance of backward recovery stresses was manifested as changes of spin-orientation. The third step is ascribed to the process of cell wall sharpening. The observation of the third and further steps was complicated by overlapping caused by magnetic transformations and ordering effects. (C) 1993 The Institute of Materials.