The Gleeble™ thermo-mechanical simulator is used for administering precisely controlled heat-treatments or thermo-mechanical treatments on specimens in an inert or vacuum atmosphere. Using the Gleeble™, a combinatorial approach has been designed in CAMM for affecting wide microstructural variations in Ti alloys in a rapid manner. Thus, the Gleeble™ allows for large variations in the heating and cooling rates which in turn can cause large variations in the microstructural features. Subsequent to the heat-treatment, standard tensile specimens are fabricated from the central region of these rectangular samples, which experiences a uniform thermal history. The existing Gleeble™ equipment was recently upgraded and updated in terms of its controlling circuitry and interfacing software. The same closed-loop digital control system with Pentium computing power and Windows-based software used on the newer Gleeble™ systems was incorporated into the existing older system. This has allowed for the optimum functioning of this critical piece of equipment, essential to the model development activities in CAMM.
The DSI® Gleeble 1500 is a horizontally-mounted thermo-mechanical testing apparatus produced by Dynamic Systems Inc., of Poestenkill, NY. The grips are fully enclosed within a vacuum/environmental chamber with a large viewing window, allowing visual monitoring of the specimen during testing. The environmental chamber and grips are large enough to accommodate traditional tensile specimens. The vacuum system is comprised of a standard piston pump and an air-cooled diffusion pump, capable of producing pressures as low as 10-5 Torr. The Gleeble can be operated either under vacuum conditions or under a partial pressure of inert gas. Heating is accomplished by electrical-resistance heating. The maximum current for specimen heating is 530 amps @ 480 volts, allowing specimen temperatures to climb as high as 3000 °C. The Gleeble is capable of heating rates greater than 10,000 °C/s, quenched cooling rates as high as 10,000 °C/s, and un-quenched cooling rates as high as 330 °C/s. The maximum force is ±80,066 N (18,000 lb) in tensile or compressive tests, while in fatigue tests the maximum force is ±53,374 N (12,000 lb). The maximum and minimum force rates are 200,000 kg/s and 1.7 x 10-6 kg/s, respectively. The maximum and minimum stroke rates are 1.2 m/s and 1.7 x 10-9 m/s. The control computer is capable of measuring stroke, crosswise and lengthwise strain (engineering and true), force, stress (engineering and true), and temperature. In addition to reading the force and stroke the computer is able to use input from pyrometers, dilatometers, and various strain gauge devices. The Gleeble can perform nearly any tensile and/or compressive thermo-mechanical test imaginable.