Nanoindentation Studies and Analysis of Mechanical Properties of Ti-4.5wt%Al Based Super Alloys with Fe Additive

Abstract

In this research, nanoindentation tests were carried out on Ti-4.5wt%Al with iron additive at varying weight percentages of 2, 4, 6 and 8 produced using Spark Plasma Sintering technique. The indentation tests were performed on the samples using 300nN and 500Nn indenter loads. Nano-mechanical properties such as modulus (EIT), elastic modulus (E), Vickers hardness (HVIT), creep (CIT), stiffness (S), plastic work (Wp) and elastic work (We) using Oliver-Pharr analysis. It was noted that at indentation load of 300nN, maximum displacement value of 2097.5nm was obtained on Ti-4.5wt%Al+4wt%Fe alloy while the least value of 444.43nm was obtained on Ti-4.5wt%+6wt%Fe alloy. It was observed that alloy with 4wt% of iron gave the highest value of both indentation modulus and elastic modulus at both indentation loads. That least creep values of 3.7% and 4.54% were obtained from alloy with 4wt% iron content for both indentation loads of 300nN and 500nN respectively. The displacement (dh) increased with increase in indentation load (dp). Comparatively, Ti-4.5wt%+6wt%Fe has the least displacement-load value, the decrease in the displacement (h) observed on Ti 4.5wt%+6wt%Fe was due to the presence of hard BCC TiFe phase which retards dislocation.Ti-4.5wt%Al+4wt%Fe comparatively has the least combined properties whereas Ti-4.5wt%Al+6wt%Fe has the best combined properties for engineering application.