February 2022 Volume 4

and microhardness measurements have been done at CSU. We have also reviewed literatu is helpful to this project. Objectives: • Investigate properties of Inconel 718. • Simulate machine failure at multiple discrete times. • Apply 2 quench techniques. • Determine impact on mechanical properties of Inconel 718 • Determine whether mechanical properties of experiment pieces are similar to the Literature Review: Introduction to Inconel 718: Prominent use is in gas turbine engines for commercial and military aircraft, reciprocating power generation, metal processing, space vehicles and marine propulsion. In 1950, 10% weight of an aircraft gas turbine engine was made of superalloys. By 1985, this figure up 50%. New jet engines are more efficient because of higher operating temperatur require higher performing components. Superalloys allow operating temperatures to incre 1200F to 1300F. Higher temperatures also result in reduced emissions because the co cycle is more complete. Inherent poor properties of IN718 are thermal conductivity, reactivity and low elastic modulus. Superior properties at high temperature, high streng surface stability, fatigue life and resistance to corrosion, oxidation and creep. Maintains s surface and property stability at elevated temperatures, under high stress and i environment. Composition of Inconel 718:

FORGING RESEARCH

Effect of Processing Variables and Die Geometry on Microstructure of Forged IN718 By Professor Tushar Borkar

The main objective of this project is to investigate the effect of processing variables on microstructure and mechanical behavior of forged IN718 alloys. The undergraduate student, Yusufi Naik has finished all heat treatment at formally TECT with the help of Russ Tischer. The mechanical testings have been performed at Element Materials Technology for room temperature as well as elevated temperature tensile testings, and stress rupture tests. The SEM characterization and microhardness measurements have been done at CSU. We have also reviewed literature which is helpful to this project. Objectives: • Investigate properties of Inconel 718. • Simulate machine failure at multiple discrete times. • Apply 2 quench techniques. • Determine impact on mechanical properties of Inconel 718 • Determine whether mechanical properties of experiment pieces are similar to the control. Literature Review: Introduction to Inconel 718: Prominent use is in gas turbine engines for commercial and military aircraft, reciprocating engines, power generation, metal processing, space vehicles and marine propulsion. In 1950, 10% of total weight of an aircraft gas turbine engine was made of superalloys. By 1985, this figure had risen up 50%. New jet engines are more efficient because of higher operating temperatures which require higher performing components. Superalloys allow operating temperatures to increase from 1200F to 1300F. Higher temperatures also result in reduced emissions because the combustion cycle is more complete. Inherent poor properties of IN718 are thermal conductivity, chemical reactivity and low elastic modulus. Superior properties at high temperature, high strength, good surface stability, fatigue life and resistance to corrosion, oxidation and creep. Maintains structural, surface and property stability at elevated temperatures, under high stress and in severe environment.

Composition of Inconel 718:

Element

Requirement (wt%)

Nickel 50 – 55 Chromium 17 – 21 Iron Balance Niobium + tantalum 4.75 – 5.5 Molybdenum 2.8 – 3.3 Aluminum 0.2 – 0.8 Cobalt 1 max Manganese 0.35 max Carbon 0.08 max

• Nickel based alloy • Use in load bearing applications at temperatures in excess of 80% of their incipient melting point. • High phase stability of FCC nickel matrix. • Strengthen by precipitation or by incorporating alloying metals such as rhenium and ruthenium. • Niobium addition to overcome cracking problems during welding. • Chrome and molybdenum addition aids in corrosion resistance. • Niobium and molybdenum effectively strengthen alloy but also result in severe segregation within the ingot upon solidification. Forging: Alloys are heated above the critical transformation (solution) temperature for the specific alloy which causes carbon and other elements to go into solid solution. Quenching or cooling solidifies the microstructure. Heated material can be cooled by air in room temperature or rapidly cooled by immersing the hot material in water, oil or other suitable liquid. Heat treatment: Materials are never used in the as quenched condition. Heat treatment is required to develop the hardness, strength and toughness of the material and to relieve the brittleness. Heat treatment leads to precipitation of and spheroidization of the carbides present in the microstructure. Temperature and times are controlled to produce the final properties required of the material. Result is a component with appropriate combination of hardness, strength and toughness.

FIA MAGAZINE | FEBRUARY 2022 72