Evaluation of elastic modulus and hardness of Fe–Al base intermetallics by nano-indentation techniques

Nanoindentation has been used to study Youngʹs modulus and hardness of Fe–Al alloys with Al contents from 22 to 47 at%, and the influence of Cr additions to near Fe3Al alloys. Materials are examined in the quenched state and the well-annealed state with, respectively, relatively poor order with retained thermal vacancies, and good order with few vacancies. Significant changes occur in both modulus and hardness, affected by Al content, Cr addition and heat treatment. These changes are discussed in terms of state of order, possible role of magnetisation, and vacancies.