Twins and twin-related domains in a grain boundary-engineered 304 stainless steel

ABSTRACT

The grain boundary (GB) network of a GB-engineered 304 stainless steel was investigated in three dimensions. The GB-engineered sample had a high proportion of twin-related boundaries (∼70%). However, these boundaries were not distributed uniformly, but rather in large-sized twin-related domains (TRDs). All grains within a TRD can be connected by a tree-shaped twin-chain. Any two grains within a TRD have ∑3ⁿ-type misorientation, where the n-value could be determined according to the twin-chain. These results show that the formation of large-sized TRDs is correlated with extensively progressed multiple-twinning processes. A quadruple-junction has three twin-boundaries at most. Furthermore, all observed quadruple-junctions within TRDs have at least one twin-boundary. The common spatial morphologies of twin-boundaries are plane-shape, tunnel-shape and semi-closed tunnel-shape.

This paper is part of a thematic issue on Nuclear Materials.

KEYWORDS:

• Stainless steel
• grain boundary engineering
• EBSD
• twins
• twin-related domain
• three-dimensional
• grain boundary network
• twin-chain

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Tingguang Liu http://orcid.org/0000-0002-3253-6817

Additional information

Funding

This work was supported by the Fundamental Research Funds for the Central Universities [grant number FRF-TP-16-041A1] and National Natural Science Foundation of China [grant number 51701017].