Mössbauer and positron annihilation studies in plastically deformed Fe72−xAl28Tix (x=0, 2, 9) alloys

Abstract Positron lifetime measurements in deformed Fe–Al–Ti alloys, obtained by filing the homogenized ingots show that monovacancies are created during the filing process. This is in contrast with known results on deformation due to rolling where dislocations have been reported as the major defect type. These results together with those from Mossbauer spectroscopy suggest that the vacancies are dominantly created due to aluminum atoms being displaced to the nearby sites where they replace iron atoms. Annealing at 900°C for extended periods caused defect concentration to greatly reduce. Positron lifetime spectroscopy has been successfully used to detect agglomeration of vacancies to form di- or tri-vacancies for the first time. Addition of titanium is found to facilitate fast removal of defects during controlled heat treatments.