Carol Martinez, “Post-Oxidation Microstructure Changes in Inconel 625”
Mentor: Benjamin Church, Materials Science & Engineering
Poster #97

The ever-increasing demand for high temperature strength and excellent corrosion resistant materials, serves as a motivation to develop high performance alloys. This led to the development of superalloys that contain various alloying elements to display the properties needed for extreme environments. Inconel 625 is a nickel-based alloy most widely used in high temperature applications such as aerospace, petrochemical, and nuclear industries. The wide application of this superalloy is attributed to its excellent oxidation resistance and mechanical properties. However, during service, the performance of this alloy deceases when operating between temperatures of 600-1000°C. In materials science it is known that changes in microstructure can impact the properties and performance of a material. Studying the evolution of materials in extreme environments is an area that can further the application of current materials. The aim of this work is to investigate the changes that occur in Inconel 625 when it is exposed to high-temperature oxidation conditions. Oxidation occurs when the alloy is in contact with oxygen or steam at temperatures above 500°C. This results in the oxidation consuming specific elements in areas near the surface of the alloy. Furthermore, the alloy develops a non-uniform composition leading to microstructural changes particularly in areas located nearby the oxidation. The testing methodology involves processing the samples inside a tube furnace with various temperatures of up to 1000°C. After the exposure, the samples were prepared by grinding, polishing, and etching in order to be characterized by optical and electron microscopy. The results gathered will provide data needed to observe microstructural changes as a function of time, atmosphere, and temperature.