Evaluation of Elastic Modulus and Hardness of Iron Aluminides Using Nanoindentation Techniques

Trabajo presentado en el MRS Fall Meeting & Exhibit: Symposium JJ : Intermetallic-based Alloys-Science, Technology, and Applications, celebrado en Boston (Estados Unidos), del 26 al 28 de noviembre de 2012Both the elastic and the plastic properties of iron aluminides are known to vary widely according to alloy composition and to preparation conditions. In the present study the Young¿s modulus and hardness are determined using nanoindentation techniques for alloys containing from about 20%-50%Al, some containing Cr additions, with materials in the quenched and in the well-annealed states. Modulus is confirmed to be low for Al contents near 25%, increasing at both higher and lower Al contents, but is also shown to be highly sensitive to both Cr addition and to the state of annealing. Hardness variations are equally complex, with hardness higher for Al contents near 25% and near 50%, depending sensitively on the state of annealing, but being independent of Cr additions. Techniques used for assessment of elastic and mechanical properties will be described, and the underlying reasons for changes in properties discussed, as well as the importance of these changes for general engineering application of iron aluminide