Mechanical behaviour of Inconel 713LC at different strain rates and high temperatures

Abstract
This paper presents the results of an experimental programme to obtain the mechanical behaviour of the Inconel 713 Low Carbon alloy at different strain rates and from room up to higher temperatures. This material is used on aircraft engine turbine blades for its excellent performance at high temperatures, and is produced by cast. The experimental work has been carried out using two testing techniques covering different strain rates and using different heating devices to achieve temperatures from room up to 850°C. The testing set-up was designed to perform compression tests on prismatic specimens and tensile tests of cylindrical specimens. Low strain rate tests were performed using a servo-hydraulic Instron machine at a constant strain rate of 10⁻⁵ s⁻¹ and a constant temperature, using a MTS short furnace. The high strain rate tests were performed using a Hopkinson bar in conjunction with a special furnace, testing at strain rates of about 10³ s⁻¹. This Hopkinson bar has been modified to test metallic materials at very high temperatures using high strength nickel super alloy bars. Stress-strain curves of the Inconel 713LC alloy have been obtained in different conditions. The materials exhibit elastic-plastic behaviour with marked strain hardening. The test results show the influence of strain rate and temperature. The material has a very good performance up to very high temperatures, even improving its yield strength when increasing the temperature. The strain rate effect is more relevant than the temperature effect; the results show that the yield strength increases about 15% at high strain rate when compared to static tests.