Visual Testing (VT) Practice Exam

A reduction in ductility due to in-service or pre-service environments is called what?

1. Embrittlement

2. Hydrogen fatigue cracking

3. Thermal fatigue

4. Intergranular stress corrosion cracking

The correct answer is: Embrittlement

The reduction in ductility due to in-service or pre-service environments is referred to as embrittlement. This phenomenon occurs when materials undergo changes that make them more brittle and less capable of deforming plastically before fracturing. Various environmental factors or conditions, such as exposure to certain chemicals, high temperatures, or mechanical stresses, can lead to embrittlement, significantly affecting the material's performance and safety. In contrast, hydrogen fatigue cracking refers specifically to the failure of materials due to the presence of hydrogen, which can invade and weaken the metal structure. Thermal fatigue relates to the stress produced by temperature changes that can cause cracking due to repeated thermal cycling. Intergranular stress corrosion cracking entails the fracture that propagates along the grain boundaries of a material due to simultaneous exposure to tensile stress and a corrosive environment. While these terms describe specific forms of material degradation, embrittlement broadly encompasses the general reduction in ductility caused by various environmental factors.