STUDY OF THE MECHANICAL PROPERTIES OF INCONEL 718 SUPERALLOY AFTER HOT TENSILE TESTS

Abstract

This research work investigated some important mechanical properties of Inconel 718 superalloy using hot tensile tests like conventional yield strength to 0.2% strain (σe ), ultimate strength (σr ), and specific elongation (εu ). Samples were strained to failure at temperatures of 600°C, 650°C, 700°C, 750°C, 800°C and 850°C and strain rate of 0.5 mm/min (2 × 10–4 s–1) according to ASTM E-8. The results showed higher values σe of yield strength at 700°C, this anomalous behavior can be attributed to the presence of hardening precipitates as observed in the TTT diagram of superalloy Inconel 718. Examination of the sample’s surfaces tensile fracture showed that with increasing temperature test the actuating mechanism changes from intergranular fracture to coalescence of the microcavities.

Keywords

• Inconel 718; Hot tensile test; SEM fractures.