Dr Yi Xiong

Dr Yi Xiong

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2017-2021 DPhil Researcher
Yi joined the OMG from Manchester to work on cold dwell effects in Ti alloys.  This is an effect through which a large reduction in fatigue life is observed for many (but not all) Ti alloys when a hold at peak stress is included in the loading cycle.  The dwell debit is most pronounced at fairly low temperatures (cold) and is not present when tests are run hot.  This is clearly of huge importance to aerospace engine manufacturers.

Yi ran a large mechanical test campaign at the diamond light source using X-ray diffraction in a transmission powder diffraction geometry to monitor lattice strain variations during in situ stress relaxation tests.  He then used crystal plasticity FEA simulations to match these experiments and extract key materials parameters describing the time dependent plasticity.  He also used DIC to measure grain resolved creep rates in large grained Ti-7Al again using crystal plasticity FEA simulations to analyse the data.

Yi returned to China after his DPhil studies.