MM504 Lecture 33a: Environmental Assisted Cracking and da/dt

Environmental assisted cracking (EAC) is a phenomenon where a material experiences cracking due to the combined effects of a corrosive environment and mechanical loading. One type of EAC is hydrogen embrittlement (HE), where the presence of hydrogen in a metal can cause it to become brittle and prone to cracking. Hydrogen embrittlement can occur during manufacturing, surface treatment, or service conditions where hydrogen is present. Hydrogen embrittlement can lead to catastrophic failure of a component if not properly addressed. Another type of EAC is hydrogen-enhanced decohesion (HEDE), which is a form of hydrogen-assisted cracking that occurs in ductile materials. HEDE is the result of the interaction between hydrogen and dislocations in the material, which leads to the formation of voids and cracks. Understanding the mechanisms and factors that contribute to EAC and hydrogen embrittlement is essential in preventing failures and ensuring the safety and reliability of materials and structures.