Ductile brittle transition temperatures of CVD and forged tungsten

This paper reports on three point bend tests that were performed on samples of tungsten fabricated in two ways: chemical vapor deposition (CVD); or powder metallurgy procedures followed by forging at elevated temperature below the recrystallization temperature. Testing was performed under a vacuum of 10-5 torr at temperature ranging from 22 C to 1000 C. Results of these tests were used to determine ductile-brittle transition temperatures for the various products. Auger electron spectroscopy was used to determine impurities present at the grain boundaries of CVD products that are believed to be occluded in the material during vapor deposition and give rise to brittle behavior at low temperatures