On the role of the process zone in hydrogen assisted cracking—II. Kinetic conditions

✍ Scribed by A. Neimitz; Elias C. Aifantis

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 628 KB
• Volume: 31
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(88)90118-x

✦ Synopsis

Following up the developments of recent work on the geometric and force characteristics of the process zone (PZ) and its role on environmental fracture we discuss here the problem of hydrogen assisted cracking (HAC) in elastoplastic material under kinetic conditions.

The analysis is based on the postulate that cracking proceeds in step-wise fashion with an average velocity determined by the ratio Au/Al,, where Au is an average crack jump length and At, the time interval between two subsequent jumps. Since Au has heen calculated in our earlier work with the aid of macroscopic considerations, emphasis is put here on the calculation of Ar, by considering the critical accumulation of hydrogen within the PZ. Indeed, this is used to formulate a chemomechanical type fracture criterion which eventually leads to the prediction of velocity vs stress intensity factor graphs.