ENVIRONMENTAL-EFFECT ON THE DUCTILE-BRITT LE TRANSITION OF HIGH-PURITY AS-ROLLED CHROMIUM

Effect of environment on ductile-brittle transition of high purity as- rolled chromium were experimentally investigated using a small punch ( SP) test in ten different atmospheres. The ductile-brittle transition temperature (DBTT) of pure chromium is sensitive to the test environme nt. DBTT under the environment of water or air is lower than that in v acuum. Also the ductility of chromium at room temperature in air is hi gher than that in a dry hydrogen gas atomosphere. The values of the SP energy are higher in a wet gas atmosphere than that in a dry gas atmo sphere. This result is contrary to the observation in high-strength st eels or intermetallic compounds in which the ductility becames poorer when tested in a wet gas atmosphere.