Correlation of Ti-6Al-4V Fractographs With Mechanical Behavior in Methanol-Acid, Methanol, and Air Environments

A series of Ti-6Al-4V tensile specimens was tested in air, methanol plus 0.3% of 1/10 normal HCI, and anhydrous methanol environments at a strain rate of 1.7 × 10−5 sec−1. Fractographic and high resolution electron diffraction examination of the fracture surface provided evidence for the conclusion that Ti-6AI-4V becomes embrittled in an anhydrous methanol environment by a form of hydrogen embrittlement. The fracture mode for the specimens tensile tested in the methanol-acid mixture was characteristic of a low-energy tear process, and the nature of the stress-strain curve suggests that this behavior is due to the Roscoe effect.