A High Temperature Hardness Testing System for Mechanical Characterization of Engineering Components

Mechanical properties of materials at high temperatures often show a significant departure from room-temperature behavior.In the study of materials science, an understanding of mechanical behavior as a function of temperature is quite valuable.One of the elegant ways to determine tensile strength of metallic alloys is to measure the material hardness, in which the hardness acts as a "strength microprobe." 1 With this aim in mind, we put together a high-temperature microindentation hardness tester by assembling various mechanical components and electrical systems for operation at high temperatures in the range of room temperature to about 1000 o C. The basic hardware components were from a commercial hot-hardness tester which was no longer functional.These components were acquired from a commercial cutting tool manufacturer for a student project.In this paper, we describe key aspects of the system operation and illustrate the application using hardness data obtained on a series of cutting tool materials at different temperatures.The unique aspect of this capability for the University is that it is the only hot-hardness testing system available in the state of Arkansas, and provides an excellent opportunity for classroom education and research on high temperature mechanical behavior of cutting tools, steels for die casting dies, tool steels, engine and turbine parts, ceramics and composites operating at elevated temperatures.It is available as a valuable educational and research tool for students and faculty, as well as to regional manufacturing industries, who may be able to use this testing service, thereby supporting the operation and training opportunities for students on an on-going basis.