Mechanical Characterisation and Study of Nickel Based super alloy 718 at Subzero Temperatures

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ABSTRACT

As we all know in nickel-based super alloys the major element is nickel and have good mechanical properties when compared to the other super alloys. Based on these properties, they are utilised in many industries like aerospace, automobiles and nuclear technology. Inconel718 alloy has high strength and resistance to the corrosion and mostly utilised in cryogenic and defence applications. In this, investigated Inconel718 specimens are subjected to the uniaxial tensile tests at different control variables like temperature varies from ambient temperature to −70°C in three different orientations 0ᵒ, 45ᵒ, 90ᵒ at one strain rate 0.01/sec. This study shows that as the temperature decreases, there is abslight decrease in yield strength and predominate increase in ultimate tensile strength.

Through scanning electronic microscope (SEM), the fracture surface behaviour of the Inconel 718 tensile sample surface at different temperatures is investigated and shows that the fracture is more ductile in nature. The normal anisotropy parameter ($\bar{r}$) and planer anisotropy ($\mathrm{\Delta }\mathrm{r}$) were measured which show the material has good formability in nature. ANN model is developed to the desired outputs with the targets by giving the mechanical properties of the Inconel 718 trained and validated as best fit of curves with correlation.

KEYWORDS:

• Inconel718
• tensile testing
• sub-zero temperatures
• scanning electron microscope
• anisotropy
• artificial neural networks

Disclosure statement

No potential conflict of interest was reported by the author(s).