What Does Brittleness Temperature Mean?
A material’s brittleness temperature is defined as the temperature at which 50 percent of the tested specimen (of the same shape and material) will exhibit a brittle mode of failure when subjected to an impact load under specified conditions.
Testing of brittleness temperature is primarily used for plastics and elastomers. Guidelines and standards for testing a material’s brittleness temperature can be found in ASTM D746 “Standard Test Method for Brittleness Temperature of Plastics and Elastomers by Impact.”
Trenchlesspedia Explains Brittleness Temperature
While many plastic components (such as plastic pipes) exhibit flexible behavior at ambient temperatures, they can become brittle at temperatures that are sufficiently low, which can severely affect a material’s ductility and impact strength. By determining the 50 percent failure rate of the test samples that fail below a specified temperature, the brittleness temperature can be determined.
In accordance with the ASTM D746 “Standard Test Method for Brittleness Temperature of Plastics and Elastomers by Impact,” brittleness temperature tests are conducted by lowering the specimen into a bath at a specified temperature using a specified specimen holder. The specimen is then pulled out of the bath and subject to an impact force at 2000 ± 200mm/s. This procedure is repeated until a failure rate of 50 percent is achieved where brittle failure is defined by the ASTM as fracture into 2 or more pieces, or formation of any cracks visible by the unaided eye.