State of 3-D micro-damage in hydrogen redistributed regions of precharged high strength aluminium alloy

• Micro-damage state formed in hydrogen redistributed regions of AA 7075 is revealed.
• H-redistribution is shown to alter the content and shape of micro-pores.
• Extended agglomerated zone is revealed for the first time near an intergranular crack.
• Embrittled damage state is shown to increase micro-pore content for H-repartition.

A comparison of the state of 3-D micro-damage induced by hydrogen redistribution due to thermal treatment and deformation near an intergranular fracture surface is carried out in high strength aluminium alloy using synchrotron microtomography. The mapping of various types of micro-damage provides evidence that hydrogen redistribution occurs along with a change in content and shape of micro-pores. The presence of intergranular cracks and an extended agglomerated micro-pore damage state are found to be in close proximity to each other, suggesting a mechanistic relationship for both formation of the unique damage architecture and insidious manifestation of embrittlement in high strength aluminium alloys.

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