Tensile testing at extreme temperatures

The push to develop ceramics and ceramic-matrix composites for applications in advanced heat engines, gas-turbine engines, and other extremely hot environments has provided a major incentive for testing-equipment builders to raise the maximum temperature capabilities of environmental chambers and furnaces. One such company, for example, now offers standard furnaces for tensile and tension/compression fatigue testing that can heat specimens to 1600 deg C (2910 deg F). The ability to heat specimens to higher temperatures, combined with special materials considerations (brittleness in ceramics, for example) has created a need for improvements in other testing accessories, including specimen grips, other fixtures, and extensometers. The progress in extensometry has been particularly dramatic. For example, a water-cooled axial extensometer is now available that will perform under strain control in tests requiring temperatures as high as 2000 deg C (3630 deg F).