Brittleness Temperature

Brittleness Temperature is of some use in judging the relative merits of various materials for low temperature flexing or impact. However, it is specifically relevant only for materials and conditions specified in the test and the values cannot be applied directly to other shapes and conditions. The brittleness temperature does not put any lower limit on service temperature for end-use products. Brittleness temperature is sometimes used in specifications.

Conditioned specimens are cantilevered from the sample holder in the test apparatus which has been brought to a low temperature (that at which specimens would be expected to fail). When the specimens have been in the test medium for 3 minutes, a single impact is administered and the samples are examined for failure. Failures are total breaks, partial breaks, or any visible cracks. The test is conducted at a range of temperatures producing varying percentages of breaks. From this data, the temperature at which 50% failure would occur is calculated or plotted and reported as the brittleness temperature of the material according to this test. ASTM D-746.