Microstructural evolution of a spinodal Cu-Ni-Sn alloy

Spinodal Cu Ni Sn alloys are widely used for bushings and bearings in aerospace and automotive applications. However, their susceptibility to softening and embrittlement during thermal exposure presents a commercial challenge. These changes have been linked to over-ageing, accompanied by discontinuous precipitation, which eliminates the desired modulated structure and metastable coherent precipitates. However, a phenomenological theory to explain the observed trends remains lacking. In this experiment, high resolution diffraction data will be acquired in situ from Cu 15Ni 8Sn (wt%) samples during exposures at 350, 400, and 450°C for 1000 mins. This will enable characterisation of the microstructural evolution. The results obtained will allow reliable quantification of the lattice parameters of the constituent phases, the wavelength of compositional modulation, the size of coherent precipitates, and the volume fraction of discontinuous precipitation.