In situ photoelectron emission microscopy of a thermally induced martensitic transformation in a CuZnAl shape memory alloy

We report photoelectron emission microscope observations of the thermal martensitic transformation in a CuZnAl shape memory alloy. The phase transformation appears at $48°\mathrm{C}$ during heating and at $42°\mathrm{C}$ upon cooling. The transformation is marked by a sharp change in photoelectron intensity, as well as a significant displacement and reorientation of surface features. The difference in the photoelectron intensity before and after the transformation is attributed to a change in work function of about $0.2\mathrm{eV}$ . Photoemission electron microscopy provides real-time information on microstructural changes and phase-dependent electronic properties.