Evolution of near‐surface deformed layers during hot rolling of AA3104 aluminium alloy

In the present study, controlled reheating and breakdown rolling experiments have been carried out and the thickness, structure and uniformity of the resultant near‐surface deformed layer have been characterised by scanning and transmission electron microscopy. High aspect ratio rolling, coupled with an increased rolling speed and rough and worn roll surfaces results in a high degree of interaction between the work roll and work pieces. This generates a shingled surface appearance with a high population of transverse surface cracks and a relatively thick near‐surface deformed layer. In contrast, relatively low aspect ratio rolling, coupled with a reduced rolling speed and freshly ground work roll surfaces generates a relatively thin near‐surface deformed layer. The thickness of the near‐surface deformed layer varies across the alloy surface and is directly related to the shingles, the surface cracks and the distribution of coarse intermetallics. Copyright © 2009 John Wiley & Sons, Ltd.