A study of the interaction of oxygen with the a2 phase in the model alloy Ti-7wt%Al

illustraton of al isoconcentration

Dr Hazel Gardner, Professor David Armstrong, Professor Michael Moody and Dr Paul Bagot, together with collaborators from Rolls-Royce plc, investigated a method to avoid the embrittlement in aluminium caused when oxygen consistently partitions away from the a2 preciptates to the a matrix.

Their proposed method by which oxygen encourages a2 formation despite partitioning away from it is set out in their paper published in Vol 185 of Scripta Materiala.  This paper also describes how nanohardness was systematically measured with respect to ageing time and oxygen concentration, which suggested that a2 precipitation is not the dominant hardening mechanism during ageing.