Metallic Materials Laboratory

The laboratory for the ENTC 207 Metallic Materials course was designed to provide the students with the opportunity to apply the theory from the lecture portion of the course. Each lab exercise is designed to follow a given lecture. Laboratory assignments include Rockwell hardness testing of steels and aluminum which is used in following labs involving heat-treating for hardening the entire piece or for surface hardening only. A solidification curve is constructed by using a lead-tin alloy to help each student understand how metals make the transition from a liquid to a solid. Tensile testing and impact testing are done so that the students can understand the relationship between the microstructure and mechanical properties of metals.

A Jominy End Quench test is performed and a graph is drawn to compare the hardenability of different kinds of steels. A lab involving the Galvanic series chart is used to aid the students in understanding electrochemical reactions and how to prevent corrosion. Strain hardening of austenitic stainless steel is followed by a recrystallization heat-treatment to illustrate the precipitation of martensitic particles and its influence on both physical and mechanical properties.

Samples of metals are mounted in bakelite, ground, polished, and etched with nitric acid and alcohol to reveal the metallurgical microstructures. With the aid of a metallurgical microscope the students learn to identify different microstructures and see how various heat-treatments produce different mechanical properties.