Predicting twinning stress in fcc metals: Linking twin-energy pathways to twin nucleation

✍ Scribed by S. Kibey; J.B. Liu; D.D. Johnson; H. Sehitoglu

• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 683 KB
• Volume: 55
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/j.actamat.2007.08.042

✦ Synopsis

Deformation twinning is observed in numerous engineering and naturally occurring materials. However, a fundamental law for critical twinning stress has not yet emerged. We resolve this long-standing issue by integrating twin-energy pathways obtained via ab initio density functional theory with heterogeneous, dislocation-based twin nucleation models. Through a hierarchical theory, we establish an analytical expression that quantitatively predicts the critical twinning stress in face-centered cubic metals without any empiricism at any length scale. Our theory predicts a monotonic relation between the unstable twin stacking fault energy and twin nucleation stress revealing the physics of twinning.