A new insight into ductile fracture of ultrafine-grained Al-Mg alloys

• DOI: 10.1038/srep09568
• Publication Date: 2015-04-08T08:49:25Z
• Authors: Hailiang Yu; A. Kiet Tieu; Cheng Lu; Xiong Liu; Mao Liu; Ajit Godbole; Charlie Kong; Qinghua Qin
• Keywords: Necking; Ductility (Earth science); Brittleness; Void (composites); Severe Plastic Deformation; Shear band

It is well known that when coarse-grained metals undergo severe plastic deformation to be transformed into nano-grained metals, their ductility reduced. However, there are no ductile fracture criteria developed based on grain refinement. In this paper, we propose a new relationship between and refinement during deformation, considering factors besides void nucleation growth. Ultrafine-grained Al-Mg alloy sheets were fabricated using different rolling techniques at room cryogenic temperatures. proposed for the first time features of microstructure near surface can used explain post necking directly. We found as grains refined nano size which approaches theoretical minimum achievable value, material becomes brittle shear band zone. This may tendency in under deformation.